Greetings!

First time poster, and perhaps new obsession with this tank of a television.

I have some experience with antique and vintage telephones, cameras, and a few Edison cylinder phonographs. Television is something that I never really expected to get into, least of all a 1957 RCA corner console 21" black and white tv.

I am learning as I go and while I have learned a great deal, I am just beginning to understand this albatross on my hands.

I will link to some of the pictures that I have posted in other forums looking for help.

Basically...I need to rebuild or find a compatible transformer. Each time I read the schematics for the chassis, I see any number of voltages coming and going to the various components. The transformer is burned up, it would last long enough to start smoking while the tubes warmed up. No surprise why the cord was cut!

I am hell bent to either resurrect this beast, even if I have to (heaven forbid) replace the kinescope with a square ish flat screen and keep the panoramic sound speakers. They sound great of course, RCA.

I have started removing components from the chassis. The old solder is being a real pain in the antenna to remove. I prefer to re-wire, solder, cap, etc., the entire piece. You can see many repairs over the years and some badly laid wire that should be harnessed, or just create a more compacted version of wiring.

I have the field service data booklet that lays everything out, that is a big help. But I am still learning to read it.

Any help would be appreciated! Ask questions and find out quickly what I don't know! I don't mind, just don't tell me to give up; that is something I no longer consider much in my life.

https://imgur.com/gallery/PQzX4jL
https://imgur.com/gallery/VsCpGws
https://imgur.com/gallery/0lauJxJ
https://imgur.com/gallery/Sl7MG5u
https://imgur.com/gallery/rz2qNDr

Greetings!

...some badly laid wire that should be harnessed, or just create a more compacted version of wiring.


Caution! Some minor issues can be caused by bundling wires or making them "neat" when the factory did not build them that way. Sweep currents of multiple amperes live with signal currents of millivolts in a TV, and moving wires from their original dress can induce sweep interference into the picture.

As an example, when I worked at Motorola, the assembly line for a given chassis had an approved sample locked in a clear plastic case, and the assemblers were told to duplicate the physical placement of all components and wires. Any question of doing it differently was run past engineering, who would change the sample and write an accompanying official change notice.

You should be able to find a transformer for that unit. Make sure you don't run a new one until you monitor the current from the 5U4 output.

Most TVs of that era used very similar transformers. If you can't find one, one from a junk chassis can be made to work without too much effort. Make sure the one you're subbing has sufficient filament current capability, or you can add a filament transformer in place of the original filament winding. You may have to add a dropping resistor if a replacement transformer has too much B+.

In any case, that's a very unique and handsome console in an era where they often weren't.

Oh, and welcome to Videokarma.

John

Others' opinions may vary, but here's my $.02 worth..

1. Service-wise, those early printed circuit layouts were the worst ever conceived, with the foil side of the boards made inaccessable:yuck::eek: (what were they smokin' to come up with that idea?:saywhat: Musta thought the design was bulletproof and would never need troubleshooting.

2. The newly-introduced small neck CRTs usually died an early death. Before proceeding any further, find someone with a CRT tester to verify that (if by some miracle) the CRT is good.

Good luck with your project. As has been mentioned, there are no points given for "neatness" in the wiring. The factory wiring layout and placement is important for the best performance. This includes which wires are against the chassis and which ones are not.

Your chassis is covered in Sams Photofact #400 folder 4. That gives the voltage and current specs for the power transformer. There is no Merit Sub listed but the Thordarson Catalog lists their 26R127 as a substitute for the RCA part number.

Others' opinions may vary, but here's my $.02 worth..

1. Service-wise, those early printed circuit layouts were the worst ever conceived, with the foil side of the boards made inaccessable:yuck::eek: (what were they smokin' to come up with that idea?:saywhat: Musta thought the design was bulletproof and would never need troubleshooting.

True. Don't have a clue what they were thinking other than having exceptional built-in shielding. I worked on a few when I was a young shaver, and my dad had me tack in the defective part on top of the board. Once the TV was running, he had me remove the circuit board and place the components as the factory did.

One good thing about it was that you had to use more technique than just shotgunning if you wanted a nice neat job. Later on, when RCA went to their "unitized" chassis (no more modules), the technique as described in the service manuals was to cut the defective part off the top of the board and solder a new one in place using the old leads. The reason is that RCA used a conformal coating on the bottom they did not want to be disturbed. I used to install those parts through the board despite RCA's admonition not to.



2. The newly-introduced small neck CRTs usually died an early death. Before proceeding any further, find someone with a CRT tester to verify that (if by some miracle) the CRT is good.

Another good point that I totally missed.

John

I have a post somewhere on here when I did my 1958 corner tv. It was my 2nd or 3rd tv I did. Took me 2 years to find a good crt close to me (I live in the sticks and didnt want to drive 100 miles), but it now makes a really nice picture and the sound is incredible. I watch westerns on it because of the rounded screen, great sound where I hear every horse sound clearly and love it.

Mine has a hot chassis but I might have the transformer you need here and will look the next day or two on a spare chassis I have that came with the good crt I bought.

I did the cut loop and crimp??? technique on a crapload of parts on the circuit boards. It took a lot of time but was a great learning experience but yes frustrating at times. Dont let it scare you. Yes, they are harder to work on than others for sure.

I did the cut loop and crimp??? technique on a crapload of parts on the circuit boards.

Loop and crimp is fine as long as it's done quickly so as not to partially melt the solder on the bottom of the board a bit. In fact, loop and crimp is overkill for durability.

Years ago I helped a guy work on an old tube guitar amp, and the sockets were brittle. Rather than risking having the metal terminal break flush at the tube socket, I cut a paper cap off the tube socket about half an inch away from the socket and laid the new part *right along side*, so they overlapped that half an inch, then soldered then together.

The guy howled a bit until I explained that parts contained on circuit boards are *only* attached by solder, and not nearly as much solder as the overlapped part had. He saw the light.

John

I have a post somewhere on here when I did my 1958 corner tv. It was my 2nd or 3rd tv I did. Took me 2 years to find a good crt close to me (I live in the sticks and didnt want to drive 100 miles), but it now makes a really nice picture and the sound is incredible. I watch westerns on it because of the rounded screen, great sound where I hear every horse sound clearly and love it.

Mine has a hot chassis but I might have the transformer you need here and will look the next day or two on a spare chassis I have that came with the good crt I bought.

I did the cut loop and crimp??? technique on a crapload of parts on the circuit boards. It took a lot of time but was a great learning experience but yes frustrating at times. Dont let it scare you. Yes, they are harder to work on than others for sure.

I don't know what the cut, loop, and crimp technique is; can you elaborate?

As to the transformer, that would be tremendous! I was thinking about rebuilding it; and, it may be worth it in the end just for the experience. I don't expect it to work once I am done with it...and since I cracked the original shell I'll have to have it machined somewhere. Not impossible.

I love the speakers, I attached my GE stereo to it and it was probably a bit overloaded on those RCA speakers, but the clarity is incredible. I'm tempted to just leave it connected to some L/C/R leads just to have Panoramic monaural sound coming from my stereo.

Caution! Some minor issues can be caused by bundling wires or making them "neat" when the factory did not build them that way. Sweep currents of multiple amperes live with signal currents of millivolts in a TV, and moving wires from their original dress can induce sweep interference into the picture.

As an example, when I worked at Motorola, the assembly line for a given chassis had an approved sample locked in a clear plastic case, and the assemblers were told to duplicate the physical placement of all components and wires. Any question of doing it differently was run past engineering, who would change the sample and write an accompanying official change notice.

I have plenty of pictures of the original wiring, so I will just follow those as guides. Thanks for the heads up!

Others' opinions may vary, but here's my $.02 worth..

1. Service-wise, those early printed circuit layouts were the worst ever conceived, with the foil side of the boards made inaccessable:yuck::eek: (what were they smokin' to come up with that idea?:saywhat: Musta thought the design was bulletproof and would never need troubleshooting.

2. The newly-introduced small neck CRTs usually died an early death. Before proceeding any further, find someone with a CRT tester to verify that (if by some miracle) the CRT is good.

As to number 2: I purchased an old CRT tester for Color/B&W from eBay. When I run 6.3 volts to the tube heaters I see a near 80% for cathode grid and cathode; if I switch it from quality to leak I don't see the indicator glow for a leak for the cathode. I'm assuming 6.3 volts is the correct test voltage, and it seems that the transformer has a 6.3 volt lead.

On sets where the IF stages are hand wired disturbing the lead dress can ruin the alignment which is not something you want to mess up.

It might be a good idea to find a 5 tube AM radio and make that your first project. The average monochrome TV is 5x as complex as an AM radio but uses similar parts so if you make a mistake Tracing it down from the schematic is much less difficult.

Phill's old radios on the internet has a lot of good beginner info and detailed write ups with pictures of TV and radio restorations he has done.

The original trans is probably shot, but it might not be. If the B+ line in that set has a hard short on it (say from a shorted original lytic cap) and you didn't pull out the 5U4 before power up the trans could just be complaining of the overload.... sometimes if you overload a transformer till it smokes but don't run it too long it will survive, but the odds of that are not high.

Good luck on your project.

You should be able to find a transformer for that unit. Make sure you don't run a new one until you monitor the current from the 5U4 output.

Most TVs of that era used very similar transformers. If you can't find one, one from a junk chassis can be made to work without too much effort. Make sure the one you're subbing has sufficient filament current capability, or you can add a filament transformer in place of the original filament winding. You may have to add a dropping resistor if a replacement transformer has too much B+.

In any case, that's a very unique and handsome console in an era where they often weren't.

Oh, and welcome to Videokarma.

John

Thanks for the welcome!

It is a very unique and handsome tv, I'm hellbent on restoring it so that I can use it the way it deserves.

What is B+, and, what do I need to worry about?

On sets where the IF stages are hand wired disturbing the lead dress can ruin the alignment which is not something you want to mess up.

It might be a good idea to find a 5 tube AM radio and make that your first project. The average monochrome TV is 5x as complex as an AM radio but uses similar parts so if you make a mistake Tracing it down from the schematic is much less difficult.

Phill's old radios on the internet has a lot of good beginner info and detailed write ups with pictures of TV and radio restorations he has done.

The original trans is probably shot, but it might not be. If the B+ line in that set has a hard short on it (say from a shorted original lytic cap) and you didn't pull out the 5U4 before power up the trans could just be complaining of the overload.... sometimes if you overload a transformer till it smokes but don't run it too long it will survive, but the odds of that are not high.

Good luck on your project.

Thanks! I think the transformer itself is shot, the inside (if you look at some of the links above you can see it) has burned more often than just my testing it about 5 times.

I've seen some scary crispy stuff work like new and I've seen some like new stuff DOA. Electricity doesn't care how ugly the path it takes is.

I would try powering the transformer without a load on it and if it don't smoke measure the secondaries (be careful* the plate winding has potentialy leathal voltage and current on it).

* Keep one hand in your back pocket and work on insulated surfaces.

This would be hilarious if after cracking this thing open I find that it works perfectly and I just had a great learning experience. And then I have to flatten and recreate the box that I broke open!

What is B+, and, what do I need to worry about?

In your schematic, you'll see the 5U4 rectifier tube.

https://i.imgur.com/AoXlB4d.jpg

That, along with the filtering capacitors, is what turns the AC voltage from the transformer secondary to the DC voltage that the TV circuits need. The 281V point on pin 2 of the 5U4 is called B+ voltage.

The term itself is a throwback to the very early radios which were powered by batteries. Radios had "A" batteries, "B" batteries, and "C" batteries.

Why it's important is that any excessive load or short on the secondary of the transformer can cause it to fail. Why your transformer failed is something we don't know right now - it could have been a bad 5U4 or a short or loading down of the 281V B+ line. It also could have just failed on it's own by developing a shorted turn or there could have been a prolonged load on it.

Monitoring the current in the B+ line and monitoring the current on the AC input side is important if we install a new transformer and want to be sure that there is no other problem in the TV chassis that would overheat or otherwise damage the new transformer.

John

In your schematic, you'll see the 5U4 rectifier tube.

https://i.imgur.com/AoXlB4d.jpg

That, along with the filtering capacitors, is what turns the AC voltage from the transformer secondary to the DC voltage that the TV circuits need. The 281V point on pin 2 of the 5U4 is called B+ voltage.

The term itself is a throwback to the very early radios which were powered by batteries. Radios had "A" batteries, "B" batteries, and "C" batteries.

Why it's important is that any excessive load or short on the secondary of the transformer can cause it to fail. Why your transformer failed is something we don't know right now - it could have been a bad 5U4 or a short or loading down of the 281V B+ line. It also could have just failed on it's own by developing a shorted turn or there could have been a prolonged load on it.


I am having trouble with black and red/black lead, when I run ac to them they hum and cause smoke. If I run hot to the red only, I seem to get more accurate readings without hum. It seems there is a short between the primary winding? What else causes a hum with just black and and red/black to black and red on incoming a/c?

You shouldn't be running AC to anything but black & red/black, nowhere else. That's the primary of the xfmr. Do this -

Remove all the tubes except the high voltage rectifier (probably 1B3)*. This removes all loads from the secondaries of the power xfmr. Now run AC to the primary (black & red/black) again. If the xfmr still smokes, it's shot.

*The 1B3's filament runs off the flyback.

You shouldn't be running AC to anything but black & red/black, nowhere else. That's the primary of the xfmr. Do this -

Remove all the tubes except the high voltage rectifier (probably 1B3)*. This removes all loads from the secondaries of the power xfmr. Now run AC to the primary (black & red/black) again. If the xfmr still smokes, it's shot.

*The 1B3's filament runs off the flyback.


It's shot. Smokeup and sizzle with no load and completely disconnected.

99.999% certain it's shot. But just to be 100.00% certain, do this:

On the off chance there's a hard short on the heater (filament) rail, disconnect the brown & brown/black wires so they 'float' free.

On the off chance there's a hard short in the 5U4 socket, disconnect the red & red/green wires* from the socket so they float free. (pins 4 and 6 respectively.)

Apply power to the primary as before. If the xfmr still smokes, 100.00% it's shot.

*Careful. There's normally around 800 - 900 VAC between these two.

I don't know what the cut, loop, and crimp technique is; can you elaborate?

As to the transformer, that would be tremendous! I was thinking about rebuilding it; and, it may be worth it in the end just for the experience. I don't expect it to work once I am done with it...and since I cracked the original shell I'll have to have it machined somewhere. Not impossible.

I love the speakers, I attached my GE stereo to it and it was probably a bit overloaded on those RCA speakers, but the clarity is incredible. I'm tempted to just leave it connected to some L/C/R leads just to have Panoramic monaural sound coming from my stereo.

My transformer wont work. Voltages are off. But there were some in 1959 that will work so they made similar ones for a few years. The Thordarson one may be easier to find.

The cut loop thing I may have typed/worded/titled wrong. Somewhere on this forum there is a picture in an RCA repair book of how to do it as they recommended it. But for a quick description you crush the capacitor, peel it all apart, and keep as long of a lead as you can, clean it, make a 180 bend, put a 180 bend on new capacitor, squeeze them together and solder. All of this while not causing stress on the board. Its not fun but there are worse jobs. There are quite a few of them if you replace them all as I did. it takes patience which i have. Some people dont. i wouldnt recommend it to anyone with anger issues, lol

99.999% certain it's shot. But just to be 100.00% certain, do this:

On the off chance there's a hard short on the heater (filament) rail, disconnect the brown & brown/black wires so they 'float' free.

On the off chance there's a hard short in the 5U4 socket, disconnect the red & red/green wires* from the socket so they float free. (pins 4 and 6 respectively.)

Apply power to the primary as before. If the xfmr still smokes, 100.00% it's shot.

*Careful. There's normally around 800 - 900 VAC between these two.


It has been disconnected completely for this last test, only power to red/blk and black. It's probably just shorted. Maybe I can I rewind the entire transformer.

http://imgur.com/gallery/GM9GuOi

Here is a view of the transformer winding. "Jim, he's dead!"

http://imgur.com/gallery/GM9GuOi

Here is a view of the transformer winding. "Jim, he's dead!"

Of all the transformers in an old TV, the power transformer is easiest to sub from a donor. You may have to fudge some parts but if you can't find an exact replacement, you can rube up one without a lot of trouble.

John

That is what I was thinking, I just don't know how you all can figure out the other voltages when I only see 280 and 260.

Otherwise I can just mock up several and make a stage/box in which to put them.

Get a Sams manual for the TV, they usually have transformer specs listed.

I showed the transformer specs from Sams back in post #5 of this thread.

That is what I was thinking, I just don't know how you all can figure out the other voltages when I only see 280 and 260.



There are only two voltages, the B+ supply of 281 and the filament supply. The filament winding is the brown and brown/black is 6.3vac and that won't vary.

The rest of the chassis voltages are based off the 281, which isn't really critical. Most old tube TVs show more B+ than when new because the AC line voltage is a few volts higher generally speaking than it was in the '50s. If your replacement transformer is a bit higher in B+, make sure you restuff your filters with higher voltage caps.

You just want to be sure the replacement transformer's filament winding can handle the current of the tubes in that RCA. More is good, less is bad.

Other than that you want to be sure the donor transformer is used in a 5U4 rectifier TV as opposed to a selenium or silicon rectifier chassis, so try to find a transformer that will put out about 280 -300 volts off the 5U4.

If you find a donor chassis, look at the schematic and it will give you a great idea it will work, or, if you're unsure, post the donor information here.

John

The replacement xfmr also has to have the dedicated 5 V filament winding for the 5U4.

That's in addition to the 6.3 V winding.

The replacement xfmr also has to have the dedicated 5 V filament winding for the 5U4.

That's in addition to the 6.3 V winding.

If you don't mind not having the 5U4 you could get a transformer without the 5V winding and use a pair of 1N4007s in place of the 5U4. I've been known to make Solid state 5U4 substitutes and use them in sets where the original transformer runs hot to reduce heater load and cool the transformer.

If you don't mind not having the 5U4 you could get a transformer without the 5V winding and use a pair of 1N4007s in place of the 5U4.

Yet another option, and an excellent one if the supply of 5U4 transformers available to the poster proves scarce. There may be more 1960s transformers laying around than '50s.

I suggested a 5U4 equipped donor by considering the skill level of the poster. A 5U4 transformer would take care of all filaments with just the B+ to tweak and likely a couple of holes to be relocated for mounting.

But something like this RCA, that isn't a historic piece, should be put back into operation even if requires some minor modification.

Looking forward to seeing it run.

John

I found this one that I pulled from a late 50's narrow neck RCA. I kept the Sams page with the transformers specs and Sams lists it as the exact same voltage/current ratings Tim posted. I'm not sure if it will physically mount the same, but there's a possibility. I've checked resistances of the winding's and they look good. If you think it will work send me a pm. USPS flat rate box will be the cheapest shipping method. But before you start investing money I'd recommend you follow Old C's advise and get your CRT tested. Also I might be upset if this transformer also goes up in smoke. ;)

https://live.staticflickr.com/65535/49670082443_7701a542b8_z.jpg

https://live.staticflickr.com/65535/49669971538_84b3747e1c_z.jpg

https://live.staticflickr.com/65535/49670516656_ae39f9a663_z.jpg

https://imgur.com/a/yalufGU


Here is a test with the CRT tester I purchased on eBay. Perhaps you all can figure out if the tube is good.

It is probably good. Not sure what the egg timer is for. CRT emission can be asleep for a couple minutes to a couple of hours in some cases but precise timing is not important, all that matters is waiting till emission eventually climbs which it appears to have done.

On all glass CRTs cathode emission is usually the only important metric. (Other defects usually aren't noticable or can be worked around with an isolation "booster" or similar.

Step .1) identify mysterious transformer for possible use.

Hi all,

I took a break to collect information and regroup. I am going tp reinstall all of the original components I removed, it will be good practice for actual replacement. I found a transformer that could potentially have come from an RCA chassis.

I'll post a link to the images, I am trying to identify primary and secondary windings to compare to my KCS116C chassis needs.

I am struggling to identify and measure ohms/volt outputs for needed voltages.

Perhaps the group can help.

Thanks!

Jordan

http://imgur.com/a/LNuBET5

Step .1) identify mysterious transformer for possible use.

Hi all,

I took a break to collect information and regroup. I am going tp reinstall all of the original components I removed, it will be good practice for actual replacement. I found a transformer that could potentially have come from an RCA chassis.

I'll post a link to the images, I am trying to identify primary and secondary windings to compare to my KCS116C chassis needs.

I am struggling to identify and measure ohms/volt outputs for needed voltages.

Perhaps the group can help.

Thanks!

Jordan

http://imgur.com/a/LNuBET5

The *first* thing I do on an unknown transformer is to check every wire to see what other wires (there is at least one) have continuity.

I then put all wires with resistive relatives into groups. Within each group, the wires that read highest resistance to each other are the outside connections, and the third wire will be the tap.

Note, if you find one wire that has no resistance friends, you have a bad transformer...:tears:

John

Are there 9 leads coming out of the xfmr?

If so, what I would do is this - First identify the center-tapped hv secondary. It'll measure a few hundred ohms. That'll get 3 leads outa the way.

Then identify the 5V and 6V secondaries. Each will read very near zero ohms. Never mind which is which for now.

The remaining winding will be the Primary, and will read a few ohms. Put the juice to the Primary, and measure what voltages you're getting out of the secondaries. Careful - there can be 800 - 900 VAC on the hv secondary.

11 leads I beleive

11 leads I beleive

Probably just another 6V filament winding.

https://imgur.com/a/E5oIWZz


Top 3:

Tan (right 11)
& Yellow Green (7)
=44.6 ohms

Tan 3
&Yellow Green 7
=26.4 ohms

Tan 3
&Tan 11
=18.4 ohms

Lower:

Tan 2
&Black and Yellow 4|
=.1 ohm

Black 1
& Black and Yellow 4
=.6 ohm

Yellow Green 5
&Yellow 6
=.1 ohm

Black 10
&Yellow Black
=.4 ohms


The numbers reflect a left to right order, they have been paired according to continuity and ohms.

So next step is to apply power to the lowest ohm pairs? The measure output voltage?

Thanks

Things don't quite add up there to me. Do you have a variac so you can bring the voltage up slowly? If I had to pick I'd say the .6 ohm pair is the primary, but with no variac I'd at least wire a 1amp fuse in series with one of the pair rather that just hit it with 120V AC and hope for the best. The 3 top wires seem a little out of balance for a normal center taped high voltage secondary.

You wouldn't happen to have a second good transformer that puts out 6V AC would you?

My process for testing unknown transformers is to connect the winding I suspect is the heater to 6V from a powered known good transformer (and measure voltages on the unknown transformers windings)...that way if you pick the wrong windings to power on the unknown you should not be over volting it by a dangerous margin.

You wouldn't happen to have a second good transformer that puts out 6V AC would you?

My process for testing unknown transformers is to connect the winding I suspect is the heater to 6V from a powered known good transformer (and measure voltages on the unknown transformers windings)...that way if you pick the wrong windings to power on the unknown you should not be over volting it by a dangerous margin.

I have an AC/DC transformer that can run 3-12 volts, I use it for testing other electronics/game systems/devices that need DC current.

Probably not what you mean. This is the first object/appliance that I am doing this kind of work with. I do have an RCA UHF tuner from 1952 that seems to work well. I can match the output signal to a digital tuner and the channel goes from snow to black accordingly. There are tubes in it that require 6v, is that assumption correct? Therefore I may be able to piggy back off of that.

I have an AC/DC transformer that can run 3-12 volts, I use it for testing other electronics/game systems/devices that need DC current.

Probably not what you mean. This is the first object/appliance that I am doing this kind of work with. I do have an RCA UHF tuner from 1952 that seems to work well. I can match the output signal to a digital tuner and the channel goes from snow to black accordingly. There are tubes in it that require 6v, is that assumption correct? Therefore I may be able to piggy back off of that.

You need AC to test the unknown transformer. The UHF tuner may have a 6V heater winding....You can check by looking at the ID numbers of the tubes in it. On most signal tubes made after 1936 the first digit of the tube ID number is the heater voltage...So a 6AG5 is a 6.3V heater and a 12SN7 is a 12.6V heater.

If you use the UHF tuners transformer to power your mystery transformer pull the tubes out of the tuner and if the tuner has only 1-3 tubes don't run it for more than 30second stints as a source for the mystery transformer. Probably still a good idea to use a 1A fuse in series with the connected winding of the mystery transformer....

The UHF tuner (which I suspect is really what collectors call a UHF converter) probably has a small transformer designed to run the heaters of 1-3 tubes...many 5 tube and higher transformers can take a heater winding short for long enough that you'll notice and switch off, but ones designed for fewer tubes are easier to kill.

You need AC to test the unknown transformer. The UHF tuner may have a 6V heater winding....You can check by looking at the ID numbers of the tubes in it. On most signal tubes made after 1936 the first digit of the tube ID number is the heater voltage...So a 6AG5 is a 6.3V heater and a 12SN7 is a 12.6V heater.

If you use the UHF tuners transformer to power your mystery transformer pull the tubes out of the tuner and if the tuner has only 1-3 tubes don't run it for more than 30second stints as a source for the mystery transformer. Probably still a good idea to use a 1A fuse in series with the connected winding of the mystery transformer....

The UHF tuner (which I suspect is really what collectors call a UHF converter) probably has a small transformer designed to run the heaters of 1-3 tubes...many 5 tube and higher transformers can take a heater winding short for long enough that you'll notice and switch off, but ones designed for fewer tubes are easier to kill.

The UHF tuner has 4 tubes, three are 6s and one is a rectifier. Would that supply the adequate voltage long enough to test?

I replaced three of the four tubes in the tuner for grins and giggles, I think the old caps are still okayish. Where I live you can't even pickup UHF, and the VHF is weak unless you get the right antenna angle, and that only gets you 3 stations! If you turn the antenna just 10° you lose out on 3 CSI's during primetime. Darn.

As to Kevin, I do not yet have a variac. I'll te-test the transformer leads today and see if I did anything backwards. I could be using the multimeter wrong, though I seem to be getting the hang of it.

Both of the elecgrolytic cans register over half their mfd's (or appear to when the meter auto adjusts) which surprised me.

Something happened to this tv that I still can't explain. What caused the transformer to short out, I suspect as has been pointed out that somewhere between low V rectifier and something caused it. If you left the unit on long enough the tubes began to heat, but no sound or picture. Just lots of smoke.

Also, can I use a homemade short check device? The 250 watt bulb in series with a switch, the transformer, and an outlet? Then measure the outputs?

It might be a good idea to find a 5 tube AM radio and make that your first project. The average monochrome TV is 5x as complex as an AM radio but uses similar parts so if you make a mistake Tracing it down from the schematic is much less difficult.

Phill's old radios on the internet has a lot of good beginner info and detailed write ups with pictures of TV and radio restorations he has done.



Not my intention to rain on your parade, but I highly suggest you heed the above advice and find yourself a transformer powered tube radio so you can learn the basics of electronics on a much less complicated set. I went back and read your introductory post, and IMO having some experience with antique and vintage telephones, cameras, and a few Edison cylinder phonographs are hardly credentials for the project you've undertaken. I understand the temptation to dive right in, but electronics is truly one of those fields where if you don't learn first, your basics, you'll forever be walking in the dark. Up until early computers, televisions were still considered one of the most complex electronic systems in existence. As far as discrete circuitry goes, they're still very high on that list.

The UHF tuner probably has decent heater winding current capacity.

You still get analog UHF out where you are at? Our last ones were gone by 2014.

Connecting the transformer to line with a light bulb in series is probably a better safety measure than a fuse.

The original electrolytic caps are almost certainly what killed your first transformer...the high leakage current overloaded the B+ winding and smoked it happens all the time on sets people try to run on original caps.
The thing about testing capacitors is most testers check capacitance at less than 9V....these caps usually work fine at 9V but in the TV have as much as 450V on them....many of these caps don't develop leakage current unless they have 25-200V on them (depends on the cap and the life it's had)...some line powered capacitor testers (like my Heathkit C3) can test for leakage at as high as 450VDC.

I know first hand that trying to use original electrolytic capacitors in a pre-1965 TV is a fools errand. I have Zenith's first c1961 consumer color TV the 29JC20...my set partially worked when brought up on a variac so I changed the paper caps in it, tested the lytics and only changed the lytic sections that measured leaky or open on my Heathkit...it was great for a few weeks then one of the good lytic sections died, I changed that and in a few weeks another 1-2 died, and a few weeks later when the next one died I finally just changed all the lytics to be done with that nonsense.
Do not power your TV chassis with the new transformer until you have replaced the electrolytic caps.

Top 3:

Tan (right 11)
& Yellow Green (7)
=44.6 ohms

Tan 3
&Yellow Green 7
=26.4 ohms

Tan 3
&Tan 11
=18.4 ohms

Lower:

Tan 2
&Black and Yellow 4|
=.1 ohm

Black 1
& Black and Yellow 4
=.6 ohm

Yellow Green 5
&Yellow 6
=.1 ohm

Black 10
&Yellow Black
=.4 ohms


The numbers reflect a left to right order, they have been paired according to continuity and ohms.

So next step is to apply power to the lowest ohm pairs? Then measure output voltage?


Nooooooooooooooo please !! Don't apply mains power to anything yet.

First off, the three tans (on top) would be the center-tapped hv secondary (one side is higher ohms than the other because there's more wire per turn with increased radius of the outer winding layers). And sorry, my guessitimation of ohmic values was quite a ways off.:o

The .6 ohm pair is probably the primary. That's where you'd apply power. But for starters, only through a variac or a resistive load like an incandescent light bulb.

Lacking a variac or a resistive load, what you could safely do is this - apply mains power to half of the hv secondary. The whole xfmr will then be in step-down mode. The voltages coming out of the other windings will be a given percentage of their normal values, probably around 20 - 30% or so. Allowing for the step-down factor, it'd be easy to identify which winding is which.

Yep, I will take a break again and just work on putting the old stuff back on the chassis as a practice step.

And review how to use a multimeter again so I can test the transformer.

I do have an old tube radio floating around somewhere that my grandfather had from the airforce. It was a set that opened like a little medical bag, halfway up from the front. Neat looking thing I need to track down, it's here somewhere.

First off, the three tans (on top) would be the center-tapped hv secondary (one side is higher ohms than the other because there's more wire per turn with increased radius of the outer winding layers).

Normally I would expect more like 2-3 ohms increase for radius on the center taped HV windings. 8-9 ohms difference would indicate a lot more turns. :scratch2:

Normally I would expect more like 2-3 ohms increase for radius on the center taped HV windings. 8-9 ohms difference would indicate a lot more turns. :scratch2:
True that. But I still think it's worth putting mains voltage on half of the hv winding, record the other windings' readings, then put mains voltage on the other half, and see if the readings are the same. Also see if voltage out of the unconnected half remains the same both ways.

Real hillbilly troubleshooting:D

See pictures. I used a RCA Senior VoltOhmyst (https://imgur.com/a/j4diRQK)

Perhaps seeing readings on a VTVM will make the readings easier.

I am about to tackle the RCA UHF tuner and see how to ground up see how something works. I still haven't found a radio to work on. My grandmother has a tube radio intercomm so I may be pulling that out of the wall. Yep. Pulling it out.

That's a timeless and venerable piece of gear. Are you zeroing the meter for the ohms measurements?

Mimi's Rangeaire Intercom AM/FM radio (http://imgur.com/a/3DW90tK)

No wires or components have been removed. This unit works well, except that all intercoms in the bedrooms and door have bwen removed. The master bedroom com no longer works, the door com speaker may still be behind the grill outside, however it has not worked in my memory. This will not be missed, and when restored, will be saved as my own intercom system for later in my own home!.

That's a timeless and venerable piece of gear. Are you zeroing the meter for the ohms measurements?

I did before I ran the series of tests. I downloaded the manual/schematic Wednesday when it arrived. I followed the process to 'tune' it and I have only two days experience with it. The ac/dc probe came today, from a B/K unit, just a random eBay find. I have just begun this whole process in a random way. I don't really now what tools to assemble, so it is just a scavenger hunt as I make small steps. I don't even know what to call the probe's connection to the chassis, a screw type sort of coax?

I love the whole nature of this ordeal and I am hell-bent. Just need to stay calm.

Tools I have:

CRT tester
RCA Senior vtvm VoltOhmyst
B/K solid state 2-channel oscilliscope
B/K Dynascan 1070 (does not have test pattern)
RCA Bias Supply
HP VHF signal generator

Projects:

1957 RCA KCS116C 21"
Rangeaire AM/FM tube radio from 1964 - learning project radio

I have been told to put the tv chassis components back together, and to find a compatible transformer. A smaller project was advised to first tackle how to restore a tube electronic, hence the Rangeaire.

Problems:
I do not know how to measure resistance in ohms, therefore it will be difficult identifying the resistors I removed from the tv chassis.
I know how to callibrate the vtvm via the RCA manual.
I know how to setup the oscilliscope via the B/K manual.
I do not know how to measure a capacitor using my DMM, even assuming the cap is dead, I cannot pinpoint whether my reading is accurate. Therefore I cannot accurately place the old tv caps unless I can trust what is written on each one. They are clearly marked with volts and +- % for identification.
The tv crt is rated good.
The Rangeaire radio does work, a little low on volume but it does work. I can study and test the caps and resistors, tubes, and voltages to learn AC/DC measurements.

Now what?

I do not know how to measure resistance in ohms, therefore it will be difficult identifying the resistors I removed from the tv chassis.

Order a fistful of brand new 1% film resistors ranging from less than an ohm to over 1 meg. With known good resistors of exact values, you can practice with your meter until it's second nature. Order resistors with the value printed numerically on them so you don't get confused with color codes. Known value resistors can also tell you if your meter is working properly..

In addition, you have to become familiar with ranges. For instance, a 680 ohm resistor is also known as a .68K resistor. A 820K resistor is a .82Meg, etc. Using known good resistors takes the guessing out.

I do not know how to measure a capacitor using my DMM, even assuming the cap is dead, I cannot pinpoint whether my reading is accurate.

If you're talking about a typical DMM that measures AC/DC voltages, resistance, and current, then you can't use such a meter. Some people use a resistance "kick" to determine a cap is good or not, but that's a waste of time. However, many newer DMMs though have a rudimentary capacitor function that checks for value.
If this is what you're referring to, then order a bunch of capacitors and learn the differences between pf, uf, and nf. NF was not used in the old days, but is more European than U.S.

There are on-line conversion calculators so if your meter says a capacitor is reading 68nf, you can plug that into a converter and find it's also known as a .068uf.

Most of these meters don't test for leakage as a good leakage tester must put the same voltage across the cap as it's rated for. For instance, a typical 0.05 400V cap may read .05 on a capacitor DMM tester, but become electrically leaky at 100V or more, well beyond the voltage a typical capacitor checker will test for.


John

Regarding the VoltOhmyst, you might have to re-zero it a few times until it warms up good.

The Voltohmist is a VTVM (vacuum tube volt meter)...it's solid state equivalent is a VOM (volt ohm meter). Modern measurement devices are DMMs which use LCDs to display a digital value for voltage, current, resistance etc...All these will work about as good as each other in nearly all cases. Seeing as you're a beginner I'd recommend a DMM as they are much simpler to use, easier to read, and don't require calibration every time you turn them on. Also if you blow up your DMM a replacement can be had as quick as a trip to your local hardware, auto parts store, Walmart etc.

The Voltohmist is a VTVM (vacuum tube volt meter)...it's solid state equivalent is a VOM (volt ohm meter). Modern measurement devices are DMMs which use LCDs to display a digital value for voltage, current, resistance etc...All these will work about as good as each other in nearly all cases. Seeing as you're a beginner I'd recommend a DMM as they are much simpler to use, easier to read, and don't require calibration every time you turn them on. Also if you blow up your DMM a replacement can be had as quick as a trip to your local hardware, auto parts store, Walmart etc.


I have a Klein DMM that is actually pretty decent. My issue is that I never seem to get the same readings unless I set it to capacitance, which I think I can trust. It doesn't measure leakage as you said. Ohm readings are the wonky thing, it will auto-range but I just don't have the experience to trust what I am reading. I need to practice measuring AC/DC, resistance, capacitance, continuity (I get this one, I have learned to purchase old appliances that still have continuity) etc.

There is a gent on youtube, Mr. Carlson's Lab, and he has design schematics you can purchase to build test devices that can check for leakage. I will be making a leakage checker for caps, he is a very informative teacher.

I am going to purchase a few replacement resistors and caps for the tv and learn to identify, charge, and test for various aspects using the DMM and perhaps practice with the RCA vtvm.

I have a Klein DMM that is actually pretty decent. My issue is that I never seem to get the same readings unless I set it to capacitance, which I think I can trust.

You MUST have a meter you can trust or you will spin your wheels. I only use Flukes, but I've had even those go wonky after a decade of daily use.

Out of circuit, there should be zero differences between readings. If you're using clip leads, make sure *those* are in good shape and reading zero ohms, even when flexed.

In circuit, all bets are off without examining the schematic.

John

BandDirector,
I would not waste my time by building a cap leakage tester.
Follow the words of the experienced people here. Don't bother testing the old electrolytic capacitors. As was said vintage (in my book older than 1980) electrolytics need replacing. All capacitors with paper internal construction should be replaced. Those types were used into the mid 1960's. Many of the available methods of measuring capacitance can be thrown off by leakage.
Capacitance measurement with the capacitor still connected to the circuit usually will not work.
Sometimes resistors can be tested while still connected, it depends on the circuit. When you measure low resistance a good electrical connection at the probes is very important.
You actually have some pretty good test equipment compared to other people just getting started working on electronics. A tube tester might be a good addition as well as another type of RF generator. You don't need it for you present projects but an isolation transformer could come in handy in the future. A variac would be useful for the transformer sort-out.
When a radio was suggested, I believe something with fewer tubes was what people had in mind, 5-6 tubes.
This website is a goldmine of information. Explore it, starting with the Beginner's section.
https://www.antiqueradio.org/welcome.htm

I have, today, received an unmolested chassis, tuner, and volume/power switch, and deflection yoke. This was a find via Radiola- the gent happened to have the same console, "Norman", KCS 116C. This chassis has a properly working transformer, so this will be a slow process of getting to know you, and getting to know how to carefully replace caps.

I have had a few successes with my Stromberg Carlson, and a friends Motorola; the latter after laying in new caps parallel to the old and replacing the vertical tubes produced an image that was remarkably watchable.

Now the fun part, replacing the electrolytic caps. My one question for wiring the filter caps- how do you tie the leads together to give you the 4 terminals (for Can 1), and 3 terminals (for Can 2)?

Electrolytic caps are polarized, right? So I need to tie in series or parallel? Do I ground using a negative from the highest capacitor? For example: can 1 will require 4 caps, 100 mfd, 40 mfd, 20 mfd and 20 mfd. Is the 100 mfd negative lead sharable as a common ground to the chassis? How do I tie these together to make 4 terminals for cirtcuits and ground?

Thanks all!

All of the new negative leads need to connect to the chassis electrically (assuming the old negative leads connected to the chassis), but it is OK to connect the negative lead of one capacitor to the chassis and then connect the remaining negative leads to the first negative lead. It doesn't matter which one you start with.

A positive lead must individually connect to the wires that went to the positive lead of the original capacitor, but must not connect to the original capacitor itself. You should end up with no wires connected to the old capacitor positive leads (or lugs). In other words, the old capacitor outer aluminum can or negative lead can remain connected, but its positive lead must be disconnected from the circuitry and not connect to anything.

This may require installing a terminal strip to provide isolated connection points for the new positive leads and the old associated wires.

If the old negative lead did not connect to the chassis, you need to provide an isolated terminal for the negative lead of the replacement as well as the positive lead.

Check my bungy-setup for my stack of electrolytic caps.

In the picture you can see a loop of plain 110v cord, joined around the chassis and locked with a bit of solder. The farthest right terminal is both grounded to the three Neg. (-) terminals on the caps, and grounded to the chassis via a piece of 110 cord. Is that acceptable for carrying that current if needed?

Two of the caps have only one line, feeding the HV circuitry, the third includes two resistors that I may just replace with newer Rs with longer *radials. (*is that the word for the leads coming off of caps and resistors?)

The Pos. (+) leads from the caps have heat shrink protecting them, and are joined to the terminal block with a bit of solder. I'll need to check to see if there is clearance when the chassis is put into the console.

So far I feel good by checking each cap on the schematic, then clipping the old, using the old leads to solder the replacement cap, and clip any remaining metal from the lead (*radial?).

Double check each cap value before replacing. Slow but steady work.

It's probably electrically sound. Most caps have low enough current that non-stranded phone wire is thick enough (but phone wire usually doesn't have enough insulation voltage rating to be ideal).

I would recommend drilling a hold in the chassis and screwing (or soldering if your iron is rated 60W or more) the terminal strip down to the chassis rather than leaving the thing supported by just wires.

Caps smaller than your thumb usually can be safely supported by just their leads if connected to solidly mounted terminals. Caps bigger than that I often use cable ties (aka zip ties)...some hardware stores stock zip ties with a screw hole eye on the ratchet end...those you can snug down on a cap then screw the zip tie to the chassis.

There are other methods like restuffing the original lytics too.

What matters is that the right points are connected together and not shorted or prone to shorting and that it's all reasonably mechanically sound (not going to vibrate apart or break under likely conditions of storage and transport).

Leads are leads...caps with radial leads have the leads protruding from one side of the cap and on a round cap they are on different points on the radius this lead location style is called radial....Caps with axial leads have one lead coming from each end and those leads form an axis line (or you could say the cap looks like the axle on your truck if that floats yer boat) and that's why they are called axial lead caps.

I'll try to solder the block to the chassis, and I have some zipties floating around of different lengths/colors.

The big problem is lengthening resitor leads.

I'll try to solder the block to the chassis, and I have some zipties floating around of different lengths/colors.

The big problem is lengthening resitor leads.

If you can mount the terminal strip at the bottom of the old can that should reduce or eliminate the need to lengthen leads.

BTW Mouser carries a variety of terminal strips that are exact matches to those used in most tube electronics they are a nice way of making a new terminal strip blend in with it's surroundings. I can post some links if you're interested.

I don't mind the little terminal blocks, they came in a big bag of 2-4 pin terminals plus a ground and mounting hole.

The issue is just where to fit the 100 mfd caps, they're about 1/3 the length of a roll of quarters, and weigh the full weight of the roll!

Overestimated the cap weight, anyway- nearly gained religion trying to get this arranged

In post #67, the 2nd pic near the top where you replaced a bunch of caps. Between 5 new caps i think their is a bumblebee cap... possible its a resistor but I think its a cap. Your schematic will tell you which it is.

In post #67, the 2nd pic near the top where you replaced a bunch of caps. Between 5 new caps i think their is a bumblebee cap... possible its a resistor but I think its a cap. Your schematic will tell you which it is.


The pic was taken before I caught that, went back and replaced it and uploaded the old pic. I'm about to finish installing the second set of lytics, then going to see what happens!

I lack about 15 caps overall to finish the recap, but the original owner of this chassis said the low volt rect had a hard glow, so I want to check to see if new filter caps eases the pull on that plate.

No life in the crt, all tubes lighting up, power on/off worked. Need to attach speaker cables tomorrow and listen for noise.

Heater in crt did glow, no images/snow on screen.

Only left it on for 5 ish minutes. So it may need to be on longer, will try more tomorrow.

Y'all. I don't beleive it. One new tube, and this happened.

:banana: Looks like the CRT has some life left in it. Is it possible you have the yoke rotated 90 degrees?

Good progress.

If it will pass a signal and you can feed it a test pattern then you can accurately assess what it still needs.

Good progress.

If it will pass a signal and you can feed it a test pattern then you can accurately assess what it still needs.

How does one find a test pattern? I have an analog VHS player, so if there was a tape with a black and white pattern that would be great.

I don't want to be over critical but I don't thing your cap installation shown in post #72 will be reliable. You should have just left the old cap where it was for appearance and added the new caps under the chassis. The way it is now only a slight slip of the new capacitors will result in a short to the chassis. New electrolytic capacitors don't have to be located exactly where the old ones are.

I don't want to be over critical but I don't thing your cap installation shown in post #72 will be reliable. You should have just left the old cap where it was for appearance and added the new caps under the chassis. The way it is now only a slight slip of the new capacitors will result in a short to the chassis. New electrolytic capacitors don't have to be located exactly where the old ones are.


I can relocate it, and I share your concern. I need to find some longer wiring, and relocate several resistors and a some of the video caps. It isn't really going to be easy to do this.

How does one find a test pattern? I have an analog VHS player, so if there was a tape with a black and white pattern that would be great.

You don't need a test pattern to start, any video will help to note gross problems.

How does one find a test pattern? I have an analog VHS player, so if there was a tape with a black and white pattern that would be great.

There are a number of ways to get a test pattern. If all you have is a VHS deck end credits often give evenly spaced horizontal lines that work for vertical adjustment and yoke rotation....a close up of a clock can be used for centering, linearity and setting proportional size of H and V sweeps to get a nice round circle.
If you also have a DVD player (especially one that can play a picture file off a USB stick) your horizons really open up. You can download test pattern DVD ISOs from the internet and burn them to disc. You can download jpeg images of patterns to a USB and play them (if your player supports that) or use a program to make a DVD out of them. Most DVD players lack RF output but do have composite video (yellow RCA or green if you set output to 480i and don't need color video) and audio output...plug that into the video and audio input of your VCR and tune the VCR to that input and the RF modulator in the VCR should pass the signal to your TV.

You could also use one of the many hardware based test pattern generators out there if you don't mind having another box in your life.

Sound is okay, fine tuning is at an extreme to get an image. Vertical sync/horiz sync is wonky.

See image

Also the bright line across the center won't go away

Scan lines are compressed on bottom and wide on top. The vertical linearity and size should adjust that, they interact to some degree. I'm pretty sure you have a sync and agc control on the back side of your chassis? I'd try adjusting the sync first and see if that allows your vert and horz to lock in better. If not, possibly the agc control needs to be advanced.

Still flickering

Need to adjust framing (or up/down split image)

Vertical linearity is still way off. So is the picture continuously rolling bottom to top? Appears locked in horizontally, but it's hard to tell from a still picture.

Vertical linearity is still way off. So is the picture continuously rolling bottom to top? Appears locked in horizontally, but it's hard to tell from a still picture.


Here is a clip from just now

https://youtu.be/SLgqi98x-hk

See attached pics for controls

If that is still a VHS player you're using for a signal source it could very well be your problem. It almost appears like a video tape not tracking. And the sync pulses are dependent on the head speed. Does the vertical hold control on top the TV have any influence on moving that black bar near the center screen up or down? I would suggest trying a DVD player though an rf modulator. You could probably even run the DVD player into an auxiliary input on the VHF player and still use it's rf output.

This is a combo device, playing a DVD

If that is still a VHS player you're using for a signal source it could very well be your problem. It almost appears like a video tape not tracking. And the sync pulses are dependent on the head speed. Does the vertical hold control on top the TV have any influence on moving that black bar near the center screen up or down? I would suggest trying a DVD player though an rf modulator. You could probably even run the DVD player into an auxiliary input on the VHF player and still use it's rf output.

The vertical knob on top does very little as far as I can tell. The flicker doesn't disappear at all, no matter how often I adjust anything. I can hear the feedback in the speakers, the frequency of the hum and the flicker practically sync. Something is causing enough disturbance, and it isn't getting filtered or properly syncronized. Also- the horizontal lines stay no matter what.

I don't know enough to figure this out. Time for the crt to probably rest a bit.

I can hear the flickering in the screen without volume

I can hear the flickering in the screen without volume
You've got a really strange problem going on there. Don't fiddle with this while the set is on, but how is the dag coating on the outside bell of the CRT? There should be some type of contact from chassis ground that presses against the dag so that it's grounded. The dag coating forms one side of your HV filter cap, the other side is a similar coating on the inside of the glass.

I drew a red arrow pointing to what "I think" is the dag ground contact wire that likely should have a tensioning spring pulling it taunt against the conductive coating. That wire should have some means of connecting to the chassis so that the outside coating is at chassis ground. If it's not grounded you'll have all sorts of bizarre artifacts because of the noise being radiated from the high voltage supply into the other circuits.

https://live.staticflickr.com/65535/50123972663_7d0d53c936_z.jpg

There is a wire bale around the bell of the tube, where should it ground to the chassis?

Is there an adjustment to increase the scanning rate of the screen, perhaps the sweep is too slow? Is sweep the same thing as saying scan rate? Someone said that earlier I think

Ordinarily that wire would be connected to the CRT mounting hardware and then a wire would go between the hardware and some point on the metal chassis. I can't say exactly where on the chassis but it should be a secure connection using a lug under a screw. Hopefully someone that's more recently worked on one of these sets can shed more light on what that hookup originally looked like.

Horizontal hold controls the scanning frequency, and from your video it sure appears to be locked.

Ordinarily that wire would be connected to the CRT mounting hardware and then a wire would go between the hardware and some point on the metal chassis. I can't say exactly where on the chassis but it should be a secure connection using a lug under a screw. Hopefully someone that's more recently worked on one of these sets can shed more light on what that hookup originally looked like.

Horizontal hold controls the scanning frequency, and from your video it sure appears to be locked.

Locked? And why can I not adjust vertical? The frame line is evident between DVD or VHS.

I cannot make the vertical fill the screen, there is a fold of the horizontal that appears to take up a small 1/3 of the bottom image. The fold disappears if I adjust the dual lugs on the vertical board. That creates hard, bright lines in the center of the screen or mid top, or mid bottom. There must be some other bad components?

Locked? And why can I not adjust vertical? The frame line is evident between DVD or VHS.

I cannot make the vertical fill the screen, there is a fold of the horizontal that appears to take up a small 1/3 of the bottom image. The fold disappears if I adjust the dual lugs on the vertical board. That creates hard, bright lines in the center of the screen or mid top, or mid bottom. There must be some other bad components?

The horizontal and vertical have separate oscillators. One can be locked in without the other. I'm not sure what you mean by dual lugs on the vertical board. But besides that there's a difference between vertical hold locking in and being able to adjust size/linearity. With all the flickering I suspect some kind of electrical interference, which is why I've sidetracked to the Dag grounding connection on the CRT.

Back to the CRT dag grounding; With the set turned off take an ohm meter and check if there's continuity between the chassis and that wire that's suppose to be grounding the dag coating.

The bell reads around 450 ohms, the wire about half.

The lugs are below in a pic, I think they are verticals.

Discovery: Top (left) is height, bottom (right) is vertical linerity. I couldn't read the words until now.

Height will backtrack as I turn towards the extreme end, instead of continuing to the bottom or past bottom of screen.

The bell reads around 450 ohms, the wire about half. By half do you mean a 1/2 ohm, or 225 ohms? If 1/2 ohm you have a reasonable connection going to ground and you can cross that off as a problem.

The lugs are below in a pic, I think they are verticals. OK those controls are potentiometers generally refereed to as pots.

Discovery: Top (left) is height, bottom (right) is vertical linerity. I couldn't read the words until now.

Height will backtrack as I turn towards the extreme end, instead of continuing to the bottom or past bottom of screen.

So how close are you to a full vertical picture now?

By half do you mean a 1/2 ohm, or 225 ohms? If 1/2 ohm you have a reasonable connection going to ground and you can cross that off as a problem.

Nope, around 225 ohms. So I guess a bad connection to the bell, and bad connection to the chassis/ground?

The image will not fill the screen, but it will get close, leaves about an inch gap at the bottom.

Nope, around 225 ohms. So I guess a bad connection to the bell, and bad connection to the chassis/ground?

The Dag coating itself will have resistance across itself, but from the chassis to the wire that contacts the Dag should be very low resistance. There's got to be a wire or sometimes a length of foil that makes that connection between the CRT mounting hardware and the chassis. I would think when you swapped chassis' that you may have run across it.


The image will not fill the screen, but it will get close, leaves about an inch gap at the bottom. And you still have the constant flicker?

If you have a clip lead(length of wire with alligator clips at each end), you could clip one end to the wire that contacts the Dag and the other to the chassis. If that makes no difference to the flicker then you can rule that connection out as a concern.

You see the silver rings with tabs pointing up and down on the back of the yoke?....Those are called centering rings and you adjust them by moving both tabs. The centering rings adjust both horizontal and vertical centering at the same time. When adjusting the vertical you have to juggle 4 controls: vertical hold(the user control near the tone knob), vertical linearity (inside chassis compartment), vertical height (near linearity), and centering....the goal is to get the most linear, centered image that fills the screen and doesn't roll...to do this you need a pattern of evenly spaced horizontal lines (which won't display even with the set out of adjustment as it is presently) preferably with some indication of the center of the video signal in the image. Then you adjust controls to center, even line spacing and fill screen on the TV (this may require going back and forth between each control repeatedly).

If you have a clip lead(length of wire with alligator clips at each end), you could clip one end to the wire that contacts the Dag and the other to the chassis. If that makes no difference to the flicker then you can rule that connection out as a concern.

Did that a few steps back, didn't stop the flicker.

You see the silver rings with tabs pointing up and down on the back of the yoke?....Those are called centering rings and you adjust them by moving both tabs. The centering rings adjust both horizontal and vertical centering at the same time. When adjusting the vertical you have to juggle 4 controls: vertical hold(the user control near the tone knob), vertical linearity (inside chassis compartment), vertical height (near linearity), and centering....the goal is to get the most linear, centered image that fills the screen and doesn't roll...to do this you need a pattern of evenly spaced horizontal lines (which won't display even with the set out of adjustment as it is presently) preferably with some indication of the center of the video signal in the image. Then you adjust controls to center, even line spacing and fill screen on the TV (this may require going back and forth between each control repeatedly).

Boy I'm glad you explained that. I was about to go there but hadn't quite figured out a good way to make sense of the whole combobulation. :thmbsp:

Question:

I have learned a good bit in a short time, especially since I had to do the full recap.
Before I start trying to really adjust and try to solve these continuing problems, what I could do is test the chassis components following the service guide. Use/learn the oscope, vtvm, create test pads with apropriate resistors, adjust the tuner to the proper mc readings, the picture and sound circuits, make sure the waves are correct, etc.

Would that potentially solve future problems? To service the set the way it would have been, would that insight add more to my knowledge base?

Question:

I have learned a good bit in a short time, especially since I had to do the full recap.
Before I start trying to really adjust and try to solve these continuing problems, what I could do is test the chassis components following the service guide. Use/learn the oscope, vtvm, create test pads with apropriate resistors, adjust the tuner to the proper mc readings, the picture and sound circuits, make sure the waves are correct, etc.

Would that potentially solve future problems? To service the set the way it would have been, would that insight add more to my knowledge base?

If and to an extent tuner alignment require expensive calibrated equipment and a very large amount of time and patience to learn compared to all other TV servicing and if you get it wrong it can be impossible to get it back...Wait a few restos before contemplating alignment.
The one exception to the above is tuner oscillator adjustment (which should center fine-tuning on channel)....your set could benefit from that and you can usually do it without significantly affecting alignment....there are almost as many different TV tuner designs as there are chassis so you need to read the manual carefully to find the correct procedure and adjustment points. Count the turns you make so if you were adjusting the wrong thing you can get it close to where it was.

Most schematics list voltages at the tube sockets anything more than 30% away from documented is likely an indication of fault. Note these voltages skew with the wall voltage in your house so if the B+ is 10% off so will be everything else...I often plug my sets into a variac and adjust the input voltage for the highest B+ rail derived from the power transformer/rectifier to be exactly what the schematic says so I don't have to factor a B+ skew into determining what the tolerance is in the socket measurements.
If measuring voltages on a live set work with one hand in your pocket and avoid getting shocked... Safety first.

You can sometimes find socket resistance charts which can also be helpful.

Scope work is often unnecessary once a set is as far along as yours is, but if you want to play around with a scope and learn how to see waveforms you can. I generally use my scope for adjusting H osc waveforms, looking for hum or other pronounced non-random noise, and when I suspect a waveform in a circuit is badly wrong and want to know exactly how it's wrong to gain insight into what is happening.

One thing I like to do when it isn't safe or practical to reach a test point with the set running is to take a couple of leads with small alligator clips on both ends and use those to hook the meter up with the set off then switch on the set. You can also get tube socket extenders but they are expensive and don't always match a needed test point.

If tubes test good and capacitors are new but a stage is performing badly the next thing I usually suspect is out of tolerance resistors...some circuits with large adjustment range like vertical I try to adjust first before worrying about resistors....the vertical could have been adjusted to compensate for a bad tube or leaking capacitor that you changed and now needs readjustment for good parts.

The vertical has a fold over at the bottom, fold is probably 4" on average, a black line appears near the center of the screen that should be the extreme bottom mask.

The vertical has a fold over at the bottom, fold is probably 4" on average, a black line appears near the center of the screen that should be the extreme bottom mask.

There's a big usually low voltage lytic on the cathode of the vertical output in most sets that can cause that...did you replace it?

I'd have to pull the chassis to look, but I don't remember a specific lytic for vertical. I can't recall which one is which, I'll look on the schematic. The lower 4 electro's are near the vertical line and height are near them, could be one of those that are 20 and 30 mfd at 50 volt. But those are new.

I see 2 pictures... looks like the vertical is running at half frequency.

jr

I see 2 pictures... looks like the vertical is running at half frequency.

jr


How do you fix that? I've swapped vert osc and vert drive tubes and it isn't that.

I see 2 pictures... looks like the vertical is running at half frequency.

jr
+1

Double check the values of the vertical stage film caps you changed and change any resistor that measures outside of its marked tolerance.

The cathode lytic in the vertical of most sets is a 25-100V 80-300uF lytic. Are you good enough at reading a schematic to differentiate the symbols for heater, cathode, grid, and plate? If so look at the vertical tube that drives the vertical output transformer and identify it's cathode and look for a lytic connected to the cathode.

The half frequency issue may be the only problem but if the foldover on the bottom persists after fixing the frequency issue check that lytic first.

Here's the vert circuit. Looks like the vert out cathode is direct to ground, so no cathode bypass cap(electrolytic). My money is on an incorrect value film cap too.

https://live.staticflickr.com/65535/50132219092_1b02e09742_b.jpg

It is certainly possible I made a mistake, I did have to go back and switch out a few caps because I would forget the 0 multiplier when reading values.

It is certainly possible I made a mistake, I did have to go back and switch out a few caps because I would forget the 0 multiplier when reading values.

That's a pretty common thing. Are you using Sams 400 folder 4 for reference or something else?

That's a pretty common thing. Are you using Sams 400 folder 4 for reference or something else?

I have an original field service guide, my local shop doesn't have that photofact. I do have a schematic for this chassis in the service manual.

I have an original field service guide, my local shop doesn't have that photofact. I do have a schematic for this chassis in the service manual.

That's probably even better because Sams changes the part location designation from the manufacture, although their photos are handy for locating components.

I pulled the chassis and I am looking/checking the caps and resistors. Let's see what happens in a bit

C515 is 2kv .001- this is original, fixed ceramic.

The blue/grn lead above the ceramic cap is from the vertical transformer, I can't which cap/res is in combo with it.

As to the dag and chassis ground, you can see the wire/springs/and chassis ground (bottom left)

Does your RCA service info have a pictorial of what capacitor values are located where on the circuit boards?

As to the dag and chassis ground, you can see the wire/springs/and chassis ground (bottom left)

That all looks good. Automatically grounds when you mount the chassis.

Does your RCA service info have a pictorial of what capacitor values are located where on the circuit boards?

Nope, just the modules with component numbers, refer back to schematic, then component index list. It has been a challenge to just stay in the same place on the map so to speak.

3 caps aren't giving me immediate readings, I should probably replace them or clean the leads.

If you're trying to measure them connected in circuit that doesn't always work. For starters just verify the values marked on the cap match the component list/schematic value. And sometimes you just need walk away and come back when you're refreshed and more able to focus.

Is the lead my yellow arrow is pointing to really soldered?

https://live.staticflickr.com/65535/50132360766_b616961b11_z.jpg

Yes. Added a bit more.

I replaced a few new caps, added a slightly higher mf cap on vertical, and reinforced the solder lines connecting the little board that is perpendicular to the main vertical board. For a hot minute or two I had a stable, non-flickering image. But it wasn't in any way centered via vert/horiz.

Here is another pic. This didn't last long when I tried to adjust it

Looking better. I only see one picture now, and primarily a linearity issue. It's possible the vertical hold, height, and/or linearity pot's are flaky. They could be open, dirty, or drifted high in value. A scope could come in real handy now to look at the vertical waveform on the grid of the vertical output tube.

Which cap did you change capacitance on and did you measure and replace off tolerance resistors yet?

Paper/film caps should not deviate from the original design values (except in cases where the original is an NLA value like .05 and you have to use the closest modern value, in my example .047).

Before you try the absolute desperation move of changing film cap values you need to measure the resistance of every resistor in the vertical circuit (Google "resistor color code" explanation of how to read value) and change resistors outside of tolerance. Tolerance is the 4th band and will be %20 for no band, %10 for silver, and %5 for gold. So for a 100 ohm %10 resistor it is bad if it measures above 110 or under 90.... carbon comp resistors almost never measure lower resistance than their labeled value let alone be out of tolerance on the bottom end....so replace every resistor on the vertical board that measures above and outside of its tolerance rating. The ones below I sometimes ignore because I know they are usually in parallel with another part in circuit (which fools the meter*), but sometimes I'll unhook one lead and measure those again when I'm being thorough.

*2 equal Resistors in parallel form a single resistor of half the value... Resistors of unequal value form a new value equal to (R1 X R2)/(R1+R2)....there are formulas for more than 2 in parallel if you Google.
Resistors in series act like a single resistor with resistane that is the sum of all the resistors in series...these maths also apply to capacitors but parallel caps are the sum and series caps divide (ie it's backwards from resistors).

Always make sure all parts are good before deviating from the original design.

If you can locate them, I would ever so slightly turn the sync stabilizer and AGC pots back and forth from their current position, just enough to see if that has any influence on picture stabilization.

This was with tweaking everything throughout the day.

This was with tweaking everything throughout the day.

It's looking better but did you go through the resistors in the vertical yet?... there's probably several off tolerance resistors and those can prevent proper linearity and height adjustment range.

It's looking better but did you go through the resistors in the vertical yet?... there's probably several off tolerance resistors and those can prevent proper linearity and height adjustment range.

*sigh, I haven't. I need to do that, resistors are still foreign to me. I am struggling to understand how they work. I will google how to read the color bands. I did visit my closest Fry's to pickup several packs of resistors of various values.

It'a just another step at this point, I'm a bit weary.

Dont give up, Im working on a '60 Philco console and just resigned to replace all the "quality" caps and resistors they used just like RCA did.

Dont give up, Im working on a '60 Philco console and just resigned to replace all the "quality" caps and resistors they used just like RCA did.

Oddly enough, I shouldn't have replaced the electrolytic used for the 3 panoramic speakers, it was working just fine. After messing with it I tore the original 8" center speaker leads and spent 2 hours trying to remedy it. Then the inevitable "pop" once I put the speaker set back in!

Once you memorize the color code resistor checks are quick and easy. Read value multiply by usually 1.1 or .9 for %10 tolerance then touch your DMM leads to the resistor and see if it's in range...you could print off a color code chart to have on hand...there were also paper color code "calculators" with wheels with colored edges and mostly covered faces there'd be a hole in the face cover such that when the edge color was lined up a number would be in the hole in the face cover.

Oddly enough, I shouldn't have replaced the electrolytic used for the 3 panoramic speakers, it was working just fine. After messing with it I tore the original 8" center speaker leads and spent 2 hours trying to remedy it. Then the inevitable "pop" once I put the speaker set back in!

Speaker crossover caps are not high failure and usually not dangerous to other parts when they do fail unless you run at very high volume. Speaker crossover caps are usually non-polarized and should not be replaced a single with polarized lytic. (You can make a non-polarized lytic with 2 polarized lytics of 2x capacitance connected anti-series meaning series with the 2 positives or 2 negatives connected together).
Almost every RCA is prone to the speaker terminal rivet breaking off... just one of that brands quirks.

The rivet did fail, and I tried to make a electric tape line wall so that the leads don't make contact with any metal. The lytic was a polarized 10 mfd 450 volt, so it was extremely high voltage, the spec calls for 8 mf at 10 volts. I have a 4.7 mf at 50 volts floating around.

Once you memorize the color code resistor checks are quick and easy. Read value multiply by usually 1.1 or .9 for %10 tolerance then touch your DMM leads to the resistor and see if it's in range...you could print off a color code chart to have on hand...there were also paper color code "calculators" with wheels with colored edges and mostly covered faces there'd be a hole in the face cover such that when the edge color was lined up a number would be in the hole in the face cover.



Speaker crossover caps are not high failure and usually not dangerous to other parts when they do fail unless you run at very high volume. Speaker crossover caps are usually non-polarized and should not be replaced a single with polarized lytic. (You can make a non-polarized lytic with 2 polarized lytics of 2x capacitance connected anti-series meaning series with the 2 positives or 2 negatives connected together).
Almost every RCA is prone to the speaker terminal rivet breaking off... just one of that brands quirks.

once taught , you NEVER FORGET!

https://en.wikipedia.org/wiki/List_of_electronic_color_code_mnemonics

The one we were "programmed" with is the 5th down on "Offensive and vulgar" list! :D

The rivet did fail, and I tried to make a electric tape line wall so that the leads don't make contact with any metal. The lytic was a polarized 10 mfd 450 volt, so it was extremely high voltage, the spec calls for 8 mf at 10 volts. I have a 4.7 mf at 50 volts floating around.

Usually you can use a machine screw with a nut to replace the rivet. I'm assuming the cap was the high pass crossover for the tweeters, in which case it needs to be close to original micro-farads for the frequency roll-off to be correct. Voltage not so critical. But the large speaker should sound pretty decent by itself.

Question- so how do you know what kind of problem the tv has if the lower part of the image is compressed, and the top lines are spreading further from each other? It would seem both height and lineirty (sp?) is still troubled. Since the image can't yet fill the screen via height, and when it does the flicker returns (linerity) and a duplicate/triplicate image appears, and dims.

So both are needing tracing the resistors, if replacing all the capacitors created the problem? Is that the logic here?

The linearity and height generally interact to a greater or lesser extent depending on the design, so trying to say it's one or the other may not help diagnose it. It's a vertical sweep problem, so you need to check components in that section whether they are attached directly to one control or the other.

Replacing the capacitors didn't create any problem (unless you used the wrong capacitance or made a wiring mistake during replacement).

Carbon comp resistors are very prone to drift in value with age and extremely prone to drift with moisture or humidity...resistors for the most part fail in ways that prevent the set from working while also reducing the risk of other parts failing in a chain reaction, but caps tend to fail in ways that damage other parts.

Some collectors (Christ Ricotta for example) change all resistors and capacitors as preventive maintenance, but most of us do the caps first and for the half of TVs where there are resistors bad enough to prevent proper opperation go back and find the bad resistors.

BTW: have you checked and or substituted the vertical stage tubes yet. If you haven't do it before the resistors because it is quicker and easier.

The linearity and height generally interact to a greater or lesser extent depending on the design, so trying to say it's one or the other may not help diagnose it. It's a vertical sweep problem, so you need to check components in that section whether they are attached directly to one control or the other.

Any resistor connected to the vertical tubes could be causing the issues the same as the ones on the height and Lin pots. The nice thing about working off a Sam's schematic is that the components for each stage are grouped together with signal in out and power connections marked so on any given stage you can easily say "it's gotta be in this cluster of 6-30 components".

I have swapped the tubes a few times, will do it again later this evening to double check. I have made a list of the resistors and their capacities/wattages/variance level and will draw my own schematic that is more blown up than the one in my service manual. I did not purchase any of the needed resistors, instead I bought all the wrong values! But I'll keep them. PW500 is the vert/height board

This blow-up may be easier to read on my end!

Swapping tubes didn't work

I have swapped the tubes a few times, will do it again later this evening to double check. I have made a list of the resistors and their capacities/wattages/variance level and will draw my own schematic that is more blown up than the one in my service manual. I did not purchase any of the needed resistors, instead I bought all the wrong values! But I'll keep them. PW500 is the vert/height board

This blow-up may be easier to read on my end!

Do you have any way to verify DC voltages on the pins of the vertical oscillator and vertical output tubes against what's shown on your schematic? Those would be measured with the set operational, so it may be a problem to reach those connections without a socket extender. Personally I would not risk measuring on the plate(pin 9) of the vertical output. If we knew those voltages it could provide us a clue as to where the problem is.

Do you have any way to verify DC voltages on the pins of the vertical oscillator and vertical output tubes against what's shown on your schematic? Those would be measured with the set operational, so it may be a problem to reach those connections without a socket extender. Personally I would not risk measuring on the plate(pin 9) of the vertical output. If we knew those voltages it could provide us a clue as to where the problem is.

There is an electronics store that looks right out of the 60s in the next town, he may have tube extenders. I found an original tv cord, interlock style, out there; plus a wall of tubes. He probably has them.

A gent earlier suggested the new electrolytics may be problematic the way I installed them. I may move them and replace the resistors next to them.

I have swapped the tubes a few times, will do it again later this evening to double check. I have made a list of the resistors and their capacities/wattages/variance level and will draw my own schematic that is more blown up than the one in my service manual. I did not purchase any of the needed resistors, instead I bought all the wrong values! But I'll keep them. PW500 is the vert/height board

This blow-up may be easier to read on my end!

You see the dashed line that represents the PCB on that schematic. You want to check every resistor right of the plate of the sync sep inside the box formed by the dashed line plus the hold pot and it's resistor.

If you don't have a socket extender another method is to use long alligator clip leads to bring hard to reach test points out from under the chassis.

You see the dashed line that represents the PCB on that schematic. You want to check every resistor right of the plate of the sync sep inside the box formed by the dashed line plus the hold pot and it's resistor.

If you don't have a socket extender another method is to use long alligator clip leads to bring hard to reach test points out from under the chassis.

Will do, I made a list of resistors I need so I'll send that to my electeonics guy to see if he has them in stock.

Replaced 3 resistors this evening, now I can't stop and clear a smaller image, nor a larger image; me thinks the resistors are now the problem.

I'm finding more failed/undervalued resistors; I wonder if this happened over time, or because I tested too early. Probably ovet time.

You do realize that depending on the circuit connections that other components could effect resistance measurements. Unless you check the schematic and check for additional connections that may effect the measurement, it is better to disconnect one side of the resistor. Some people take the position that if you solder one side you may as well un-solder the other and replace it anyway.

You do realize that depending on the circuit connections that other components could effect resistance measurements. Unless you check the schematic and check for additional connections that may effect the measurement, it is better to disconnect one side of the resistor. Some people take the position that if you solder one side you may as well un-solder the other and replace it anyway.


You only need to clip a lead if the resistance tests low (and you are suspicious of it) if it tests at nominal value to the upper tolerance limit the resistor is probably just fine... examining the circuit for parallel resistors or inductors is advisable with this approach.

I tried clipping to measure, found normal ranges. Still have the dame image issue; however, I cannot return a clear, non-flickering image like previous.

I think it's time to triple check wiring and soldering, especially of electrolytics. (Any electrolytic wired wrong may be damaged and may need to be replaced.)

BUT, first I would suggest walking away from it for at least three days, forgetting about it, and then taking a look with fresh eyes. I think everyone has experienced looking at a problem repeatedly without seeing something obvious when you are frustrated, and that could be the case here.

Maltese Falcon

There is a component on schematic of the vertical sweep circuit area that you posted that is labeled PW500-A. It is probably a "couplate" (there are other names for the type), a collection of capacitors and resistors on a small ceramic plate. Couplates have many leads. They are difficult to test completely. Pretty difficult to find replacements for them but from the SAMS info they can be built from scratch.

There is a component on schematic of the vertical sweep circuit area that you posted that is labeled PW500-A. It is probably a "couplate" (there are other names for the type), a collection of capacitors and resistors on a small ceramic plate. Couplates have many leads. They are difficult to test completely. Pretty difficult to find replacements for them but from the SAMS info they can be built from scratch.

I have a second chassis for this tv (chassis A), it is the original with a dead main transformer. The chassis currently in use (chassis B) was recently found and purchased from TheRadiolaGuy.

I can pull boards from it if needed (chassis A), I checked the little board today (chassis B) and found correct components, soldered a few spots on it and on the PW500. Still stuck with a flickering split image (chassis B).

I may take a break from the working chassis (B), and disassemble the other boards on the dead chassis (A). I am VERY lucky to have a duplicate of everything; including the Height/Vertical Linearity pots (it is one unit), it may be failed on the working chassis (B).

The resistors inside the double Height/Vert resistor unit/pot may be bad.

I keep forgetting the horizonalt/vertical deflection yoke, could that be the culprit? I am going to slow down and study the schematic and redraw my own version so I can comprehend, or see what I may miss.

I keep forgetting the horizonalt/vertical deflection yoke, could that be the culprit? ...

No, that is not a yoke problem.

Edit: it looks like the vertical sweep frequency is way too low, about 1/2 the correct value of 60 Hz. There must be a component that's way off value/open or not connected properly.

I ordered 2 replacement vertical output tubes, still cannot get the center bar to sync, and the picture refresh is still too slow. Moved the electrolytics to safer spots and added in new solder/junction spots.

I tried to start testing using a signal gen, oscope, bias, etc.; no golddurn clue what I am doing!! And never have enough probes, or a diode tester, or proper attenuator pads, etc. I need to make some testing pads, get some raw coax, proper connection points, etc.

Is there a way to just 'reset' or reverse/speed up the refresh rate ? Is that what sweep means? There are some things I sort of understand, but no where near what I would prefer!!

...

Is there a way to just 'reset' or reverse/speed up the refresh rate ? Is that what sweep means? There are some things I sort of understand, but no where near what I would prefer!!

Yes, picture "refresh" rate is the rate at which the beam sweeps vertically.

To repeat: sweep rate being off by a factor of two indicates that there is a bad/wrong value component or mis-wired component (or multiple) components. To find miswiring,
1) look at each point where multiple components connect and verify you have the same components and same number of components connected to that point that the schematic indicates.
2) look at each component and verify where each end is connected.

Patience is necessary!

I didn't realize how long it really takes to study a schematic. It has taken me weeks, with the chassis, to really start to follow the layout. It isn't easy when the components aren't appearing where you think they should be!

You might benefit from downloading "Television Simplified" by Kiver.

https://worldradiohistory.com/BOOKSHELF-ARH/Technology/Television-Simplified-Kiver-5th-1955.pdf

Of course you still have to get good at reading schematics.

EDIT: While on the subject of this book, it was printed in 1955 so some things (like CRT deflection angles) changed through the years after that that.
I suggest you start with Chapter 1, The Television Field, then Chapter 9, CRTs, then 10, Power Supplies, then 12, Synchronizing, lastly Chapter 13, Deflection.

The vertical sweep frequency (refresh rate in modern computer monitor parlance) is set by the RC (resistor capacitor) time constants of components in the vertical circuit.

It does take time to read a schematic when you're new to it and PCBs often slow down the process as it's difficult to tell which component leads from parts on top are soldered to which points on the bottom...I tend to use a small flashlight to locate pads and or a DMM meter with a continuity beep mode to speed things up.

Did you read all the values off the original caps or did you recap off the schematic? Sometimes the schematic has the wrong value due to a typo....

About 12 years ago when I was in highschool my first TV restoration was a 1954 Zenith...it was full of bumbelbee capacitors and I didn't know how to read them when recapping the set...so I changed all the caps based off the values on the Sam's schematic. The video detector diode in mine was bad so I had no video to judge sweep performance....then I had to move from Florida to Wisconsin and things got put on hold and I no longer had a parts budget or the parts I removed from the set. I was able to fix my video detector and discovered my vertical had the opposite problem it's sweep frequency was twice what it should be so the image looked like you cut a slide in half, overlaid the two and projected it. At that point I traded the circuit found the resistors and caps were good according to the Sam's. Schematic, but that one vertical cap in the Sam's schematic was a factor of 10 different from the Sam's parts list....so Sam's had a typo. Without the original part to confirm and no cap supply or budget back then to try the other cap value I fixed it with what I had: a resistor decade box and a bag of scrounged resistors. I used the decade box to find a value that would work (trying it on different resistors in the circuit) then once it was right I added in a fixed resistor of the same value.

While the decade box method did work for me I wouldn't recommend it except as a very last resort.
If I wasn't flat broke back then I would have tried the other cap value first. Also it's safer to change capacitance than resistance since resistors can change tube bias and overload tubes causing premature failure of affected tubes.

Don't think of using the decade box till you have verified each resistor is in tolerance, each cap is the right value and everything is connected to the right points and tube subs have been tried...(also worth while to walk away from the project for a week or two, forget about it, and then check your work with fresh eyes...it's easy for a mistake to be staring you in the face and some mental block stops you from recognizing it (it happens to even the best of us).

You might benefit from downloading "Television Simplified" by Kiver.

https://worldradiohistory.com/BOOKSHELF-ARH/Technology/Television-Simplified-Kiver-5th-1955.pdf

Of course you still have to get good at reading schematics.

EDIT: While on the subject of this book, it was printed in 1955 so some things (like CRT deflection angles) changed through the years after that that.
I suggest you start with Chapter 1, The Television Field, then Chapter 9, CRTs, then 10, Power Supplies, then 12, Synchronizing, lastly Chapter 13, Deflection.

Downloaded it, this looks like a great read. Thank you!

I did replace using both the printed value on the paper caps, and using the RCA printed service manual schematic.

I do have chassis A (the original), and it does appear to have some newer caps on the vertical board, I may remove that PCB 500 and use it as a model to test all the component values that I am still troubleshooting.

Here is the 'original' (chassis A, that came with this television) PCB board for the vertical oscillator and sync output unit.

It appears that the caps have been updated from the older paper caps, chassis B (the one in the tv) had the older paper caps.

Assuming this television properly worked at one time, I have not removed any of the Rs and Cs from this board. I will match the components to their values in the RCA service manual scheme.

I've been practicing removing boards from my backup chassis. I have learned that I am NOT a fan of clipping and resoldering caps and resistors just to test them. If that isn't best practice, too bad; this project needs to wrap up. I have every confidence that what I am doing by checking each object is a much safer, time friendly (I'm an unemployed teacher with plenty of time!) and I feel that basic step by step is simply the way to go. It will make testing poorly functioning components much easier.

I have a full set of back-up wiring, a separate chassis, and a duplicate of all parts minus a functioning main transformer. This is what I have learned:

1) Slow down and triple and quadruple check each action
2) Study the schematic and check whether there is a misprint (thanks, gents)
3) Refer to the old (chassis A) boards, someone did a decent repair job replacing 90% of the paper capacitors
4) Don't be bothered by placing and testing this chassis (chassis B, the replacement bought from 'Sonny' aka Radiolaguy that happened to have this exact 'Norman' RCA 21-D-8628 model) back in the set.
5) Any issue is starting to make some sense with everyone's help! Not to mention that excellent book link posted above.

Voila!

Still needs some work. Horizontal sweep is a little edgy
Sound is funky

:thmbsp:

Voila!

Still needs some work. Horizontal sweep is a little edgy
Sound is funky

Looking very good. :cool:

Nice work.

Her head does look a pinch stretched. It could probably benefit from tweaking the vertical pots and centering with a crosshatch test pattern or a circle that touches top and bottom, but the untrained eye isn't going to notice it as easily as many of us would.

Nice work.

Her head does look a pinch stretched. It could probably benefit from tweaking the vertical pots and centering with a crosshatch test pattern or a circle that touches top and bottom, but the untrained eye isn't going to notice it as easily as many of us would.

Although the scan lines look quite uniform top to bottom.

Although the scan lines look quite uniform top to bottom.

I couldn't see any scanlines till I zoomed in just now, but your right....maybe that lady just has a funny shaped head.:scratch2::D

I couldn't see any scanlines till I zoomed in just now, but your right....maybe that lady just has a funny shaped head.:scratch2::D

If it's who I think it is she's a very tall lady.

https://www.tasteofhome.com/collection/julia-child-facts/

Julia Child was 6' 3", though she would often tell people 6' 2" (take with a grain of salt, it was quoted from a book after her passing; though she and the writer worked together) so I think that her height, camera angle, and the receiver just fudges her head a bit.

On Monday I was trying to adjust height and the vertical board sparked and probably killed a few components, and the vert osc tube. So, today I have completely disassemled the board, and I am going to replace some of the wires that have some melted insulation due to my poor soldering. I am betting that while holding my penlight and screw driver, I accidentally touched the chassis and must have made contact with the printed board area near the osc tube. I am going to check every component for resistance, capacitance, and continuity.

A thought that has annoyed me since a few weeks back has been the linearity and height pots, they are inside a shared housing to make adjustment easier. Included is a picture.
The pot on the right is from chassis B (the replacement), the left is from chassis A (the original that was in tv at pickup). When I compare resistance measurements to the printed schematic and part list, the chassis B height shows no resistance past the midpoint when turning clockwise, nor continuity between opposite ends. Chassis A's linearity reads an appropriate half-way between 1.5 meg ohms. And, chassis A's height reads correctly at half-way between 5 megohms, and continuity between opposite ends, show near 5 mohms.

I am going to assume that I was the cause of this and open the chassis B pots up to observe the layout. It is possible I could find a 5 mohm pot to replace, or is that not possible? Anyway, I am going to reassemble the entire board using a tested component per the schematic/value/etc.

Also. The serial numbers on the parts are either 8 siblings away from each other, or I don't know. The chassis numbers are further apart I think. Chassis A (original) is KCS 116C RVB 274, 74 33 L3, Chassis B (replacement) is KCS 116C 274, 74 52 L3.

Julia Child was 6' 3", though she would often tell people 6' 2" (take with a grain of salt, it was quoted from a book after her passing; though she and the writer worked together) so I think that her height, camera angle, and the receiver just fudges her head a bit.

On Monday I was trying to adjust height and the vertical board sparked and probably killed a few components, and the vert osc tube. So, today I have completely disassemled the board, and I am going to replace some of the wires that have some melted insulation due to my poor soldering. I am betting that while holding my penlight and screw driver, I accidentally touched the chassis and must have made contact with the printed board area near the osc tube. I am going to check every component for resistance, capacitance, and continuity.

A thought that has annoyed me since a few weeks back has been the linearity and height pots, they are inside a shared housing to make adjustment easier. Included is a picture.
The pot on the right is from chassis B (the replacement), the left is from chassis A (the original that was in tv at pickup). When I compare resistance measurements to the printed schematic and part list, the chassis B height shows no resistance past the midpoint when turning clockwise, nor continuity between opposite ends. Chassis A's linearity reads an appropriate half-way between 1.5 meg ohms. And, chassis A's height reads correctly at half-way between 5 megohms, and continuity between opposite ends, show near 5 mohms.

I am going to assume that I was the cause of this and open the chassis B pots up to observe the layout. It is possible I could find a 5 mohm pot to replace, or is that not possible? Anyway, I am going to reassemble the entire board using a tested component per the schematic/value/etc.

Also. The serial numbers on the parts are either 8 siblings away from each other, or I don't know. The chassis numbers are further apart I think. Chassis A (original) is KCS 116C RVB 274, 74 33 L3, Chassis B (replacement) is KCS 116C 274, 74 52 L3.

The secon pic shows the inside of both chassis A and B's linearity and height controls. The screwdriver tip is pointing at the dead part of the resistor material, before that spot I get a reading, after (towards the right edge terminal) there is no reading.

Accidental post! But I think I killed a few caps by playing around. Extra lines, doubled screen, etc

Here is what I am talking about. The lines at the top are wider, anr the image is sort of duplicated on itself. The flicker is gone, but the horizontal has some 8-12 lines drifiting and circling the images. Sort of like a lack of horizontal hold.

Those dual pots assemblies are going to pretty difficult to source. The 137 is EIA code for manufacture CTS,followed by the date code. Apparently those were custom manufactured for RCA. It's possible the resistance elements are interchangeable with some individual printed circuit board style pots. I suppose Mark Oppat would be the guy to ask about that. https://www.oldradioparts.net/controls.html

At any rate it looks like your second set is still usable?

[QUOTE=Kevin Kuehn;3226591]Those dual pots assemblies are going to pretty difficult to source. The 137 is EIA code for manufacture CTS,followed by the date code. Apparently those were custom manufactured for RCA. It's possible the resistance elements are interchangeable with some individual printed circuit board style pots. I suppose Mark Oppat would be the guy to ask about that. https://www.oldradioparts.net/controls.html

At any rate it looks like your second set is still usable?[/QUOTE

They are, I put them in yesterday.

Don't bother with those if you can help it, it may have been trashed by a "tin whisker". Call Moyer Electronics, 570-286-6708 - Bill will be happy to sell you that part.

The OEM RCA parts are thier specialty, so odds are he has it. I just got two flybacks for two Philco sets there I gave up looking for long ago!

I keep taking breaks, and getting back to this point tells me that K fried some stuff last week. The grounding on the vert board wasn't secure and something popped and flashed last week. So I probably fried some of the caps, even though the caps have mostly high voltage tolerances. I probably need to pull the subassemnly for the vertical board, there are 7 different caps of varying values. Or I need to check tubes, I'll swap tubes first.

This is after tube swapping. There is a lot of buzz in the volume.

This is after tube swapping. There is a lot of buzz in the volume.

Very sweep is running at twice frequency.

The short is more likely to have fried a resistor... Especially if you used all 630V caps and B+ is no bigger than 450V.
If you shorted the height/Lin pots you especially want to check resistors in the B± boost supply if this set uses boost to feed the vertical.
Boost is a circuit that recovers energy from the flyback and uses that energy to supply high voltage ~1000VDC to the vertical and sometimes CRT G2.

I'm 90% certain this set has a B+ boost. I tend to see the circuit lines each time I look at the schematic. I tested each resistor for it's capacity, they were all within a 10% range, some a little moreso.

What bothers me is that I keep forgetting to sit down and trace the current lines through the vertical and horizontal. Assumption tells me that the main transformer's job is to power every 'area' (vert, audio, video, horiz) at once. So, timing the travel of current through each area is the job of the caps and resistors. If something is doubled...we assume it could be a resistor?

How did you narrow to think to B+ vs. vertical or horizontal?

Here is where I see B+ boost running through vert circuitry. So checking/replacing these resistors may be a place to start?

What bothers me is that I keep forgetting to sit down and trace the current lines through the vertical and horizontal. Assumption tells me that the main transformer's job is to power every 'area' (vert, audio, video, horiz) at once. So, timing the travel of current through each area is the job of the caps and resistors. If something is doubled...we assume it could be a resistor?

How did you narrow to think to B+ vs. vertical or horizontal?

Yes and no. If by main transformer you mean the power transformer that converts 120V from the power cord into 6.3v for the heaters and several hundred for the B+ rectifier you are not understanding a DC power supply properly.
The filter capacitors in a B+ system do not time power to different circuits. Those circuits are all getting all the power all the time.
Look at it this way...A capacitor is like a short circuit to AC but like an open circuit to DC. An inductor is like an open circuit to AC but like a short circuit to DC. Resistors behave the same to AC and DC. The filter capacitors in a B+ supply are connected between B- and B+ effectively shorting out any AC on the supply regardless of whether the AC is ripple from the rectifier or ripple from a load. (A high power load like the audio output transformer might only draws significant current (sagging the supply voltage) at peaks of the audio waveform thus the AC of the audio gets superimposed onto the B+ from loading....Or atleast it would if the filter caps weren't shorting that AC out of the B+ rail. You should not need to think about current fluctuations on the B+ rail as long as rail voltage is correct.

Film caps in vertical stages are oftentimes charged and discharged such that the voltage across them changes radically and those can control time constants... they are often wired together with tubes and resistors into something akin to an overcomplicated Japanese water pendulum resistor fills cap with charge to a certain threshold that kicks on tube to discharge cap, cap empties and tube switches off and the cycle repeats. Vertical sync essentially dumps a bunch of energy in to try and trip the tube early... vertical hold being a circuit to change the fill rate such that the circuit is close enough for the pulse energy to trip the tube but not tripping the tube before the pulse. The average vertical multivibrator circuit uses more than 1 RC circuit to get the sawtooth deflection waveform.

It's getting late and I'm starting to think I'm making things more confusing so I'll stop.

Found a blown resistor (I think) on the video board.

Found a blown resistor (I think) on the video board.

That's definitely shot. Time to replace it.

I'm swapping chassis boards, and still having horizontal deflection issues, as opposed to the previous vertical deflection issues.

Back to tracing circuits!

Grounded the video tubes, adjusted a bunch of pots. Somewhere there is a sneak resistor that is doubling or halving something! Still a duplicate image.

Success!

Turns out I had about half the vertical resistors in the wrong places. I'm not sure how I did that, probably my scatterbrain.

There is still a hum in the sound, it's coming from the vertical linearity/vertical drive. The buzz changes when you adjust it.

There is a cloud across the horizontal, about 1/3 on the left side. Any ideas? The horizontal will tweak/pull inwards and back out every 5 minutes or so.

https://youtu.be/2EGwsVmAxTo

Here is a clip of what I am talking about.

The horizontal drive may need to come in a bit, then adjust height and linearity to tighten.

The images are getting better with tweaking the linearity and height/vert hold.

Just a few things-

A) the hum from the vertical oscillator tube, going into the audio output, I'll change some tubes

B) the vertical still spreads at the top of the picture, when it settles, the image stretches and locks in. How to stop?

I'm walking away and calling this a temporary victory!

See if that shows more of what I mean.

Interesting development, you can hear a change in the vertical oscillator circuit when it cycles slower/faster. Three or four lines appear at a diagonal from the top of the screen, the buzz becomes audible, then the buzz disappears along with the lines. If you adjust vertical hold to clear the lines, the sound cycles in and out (from the vertical oscillator circuit) and the lines do not appear.

Interesting development, you can hear a change in the vertical oscillator circuit when it cycles slower/faster. Three or four lines appear at a diagonal from the top of the screen, the buzz becomes audible, then the buzz disappears along with the lines. If you adjust vertical hold to clear the lines, the sound cycles in and out (from the vertical oscillator circuit) and the lines do not appear.

Sounds like you're describing the effect of Copyguard pulses in the video. What is your video source?

DVDs of old television shows. Should I substitute vhs copies of everything?

Popped in a VHS tape, no audible buzz in audio. Bummer.

Source is a 2011 VHS/DVD/DVR combo tuner.

The Copyguard is intended to mess up recording the DVD onto another device, and is not supposed to affect TV sets. However, your set seems to be sensitive to it. There may be nothing broken in the set, but it may need some adjustment of the sound or IF alignment. But don't try to go there yet! It requires proper equipment and cannot be done by random adjustments, which will just make everything worse.

Try adjusting the fine tuning one way or the other and see if the buzz goes away. If it does without messing up the picture, it may be an acceptable fix for now.

Macrovision Copy guard was recorded directly onto many commercial VHS releases and it exists as a flag in commercial DVD releases....the interesting thing about DVD is the player generates the copy guard signal and some DVD players allow you to turn off copy guard output in the hidden service menus. You can get boxes that remove copy protection from any video source and I consider them good to have.

Sets made prior to the mid 70s predate copy guard and thus their circuits often handle the unexpected signal in undesirable ways...heck even the last analog TV stations circa 2009 would bug some older sets with things like closed captioning in the vertical blanking interval and other junk that got tacked on to broadcast TV signals after transistors became dominant.

A good copy guard removal box will scrub most troublesome things from the signal.

The Copyguard is intended to mess up recording the DVD onto another device, and is not supposed to affect TV sets. However, your set seems to be sensitive to it. There may be nothing broken in the set, but it may need some adjustment of the sound or IF alignment. But don't try to go there yet! It requires proper equipment and cannot be done by random adjustments, which will just make everything worse.

Try adjusting the fine tuning one way or the other and see if the buzz goes away. If it does without messing up the picture, it may be an acceptable fix for now.

I have most of the equipment, but I am way ahead of your advice. I've messed with the sound, I-F, first video, second video, etc. Don't know how to use the equipment, so that is the next step

Getting the right cords, terminal leads, insulating from chassis/probes, sweep generator, vhf signal, etc.

Here are the directions from the field service manual to adjust sound, sweep, and picture IF.

I have an RCA Senior VoltOhmyst, an HP VHF oscillator, an RCA bias supply with 3 outputs, and a BK Precision Model 1470 scope.

I don't know how to use the scope and signal generator. So that is the next learning project. Once that challenge has been addressed, the only thing left would be to find a color set and decide which would be better to keep in the long run.