Dang, this puppy's got some interesting early circuit topologies. The CRT is driven with video at the grid instead of the cathode, and brightness control is done via the cathode, the reverse of later standardization. And AGC is via a simple detector-driven, non-delayed type just like the AVC (automatic volume control) circuit in AM radios. And the damper is placed differently in the flyback's DC path than in later standardization, wherein B+ is supplied directly at the damper's plate.

Interesting study in the evolution of TV design.

There seems to be a design error here. The Sam's doesn't show what the HV is, but a 16GP4 typical operating voltage is 12KV. If they were actually operating it at 12KV, the Peak Inverse Voltage that the HV rectifier would see is slightly less than twice this. A little under 24KV.

The 1X2 is rated at 15KV PIV. So, it would break down. They're probably running the 16GP4 at 10KV or less, maybe 9.5KV. That would still cause the 1X2 to break down.

The 1X2-A, and 1X2-B are rated at 20KV PIV, the 1X2-C is rated at 22KV PIV.

If you can find a 1X2-A,B, or C then it would probably work without the modifications you made.

John
Just a little ditty for the "outside the box thinking" department , i wonder if at some point the flyback could've been replaced with one putting out higher HV, intended to drive a larger CRT. :saywhat:

Just a little ditty for the "outside the box thinking" department , i wonder if at some point the flyback could've been replaced with one putting out higher HV, intended to drive a larger CRT. :saywhat:

And even if they didn't replace it with a higher HV flyback, it looks like the original design was on the ragged edge.

Wonder how difficult it would be to convert it to a 1B3. :nerd: Or better yet, for ease of conversion, a SS stick rectifier. Does anybody know where those can be obtained nowadays, other than out of a junked BW set of 1970s-'80s vintage? One fella on here converted an old BW Admiral, using a HV stick from a Quasar color set.

I think the main difficulty would be putting in an Octal socket to replace the Noval socket. I suppose one could make a socket adapter without too much trouble.

There seems to be a design error here. The Sam's doesn't show what the HV is, but a 16GP4 typical operating voltage is 12KV. If they were actually operating it at 12KV, the Peak Inverse Voltage that the HV rectifier would see is slightly less than twice this. A little under 24KV.

The 1X2 is rated at 15KV PIV. So, it would break down. They're probably running the 16GP4 at 10KV or less, maybe 9.5KV. That would still cause the 1X2 to break down.

The 1X2-A, and 1X2-B are rated at 20KV PIV, the 1X2-C is rated at 22KV PIV.

If you can find a 1X2-A,B, or C then it would probably work without the modifications you made.

John

I have a 1X2B. According to my HV probe the 16GP4 is running at 14-15kv right now without the immediate sparking failure on the 1X2 which would be at 28-30kv PIV? It sounds like the 1X2 isn't going to last that long if I'm running it that far over spec. The CRT might not be happy running that far over spec either! One other thing that I have been pondering is what kind of X-ray emissions the 1X2 might be putting out with the voltage that high.

Xray emission from the rectifier happens only during electron bombardment of the plate, which occurs only during the positive-going half cycle, and the max voltage is half the PIV value. The only real concern over Xrays was in color sets where 25KV on the pic tube anode was typical, and that hype was hugely overblown (IMHO). Heck, if Xrays were any danger i oughta have been thoroughly cooked many years ago. :o

I actually have a SS stick rectifier that I found in a box of tubes that I got for cheap in a swap meet donation auction. Not sure what to do with it, but will probably keep it as a diagnostic tool/spare for sets with open HV fill windings.

Tom C.

I have a 1X2B. According to my HV probe the 16GP4 is running at 14-15kv right now without the immediate sparking failure on the 1X2 which would be at 28-30kv PIV? It sounds like the 1X2 isn't going to last that long if I'm running it that far over spec. The CRT might not be happy running that far over spec either! One other thing that I have been pondering is what kind of X-ray emissions the 1X2 might be putting out with the voltage that high.

They list the maximum anode voltage for that CRT at 14KV. 15KV isn't going to kill it, but it doesn't help.

Does your probe have its own meter or does it plug in to your multi-meter?

old_coot88 is right about x-ray production only occurring during the positive going half cycle which causes electrons to bombard the plate. However, they don't even have half the PIV. The forward drop on these tubes is between 80-200 volts. The electrons only get accelerated to that energy. Those x-rays will never make it out of the 1X2.

If there was a failure of the 1X2 such that the forward drop was as high as half the PIV, then you'd have higher energy x-rays, but the cathode emission would be so low at this point that the x-ray dose rate would be very small because of the very low current.

They list the maximum anode voltage for that CRT at 14KV. 15KV isn't going to kill it, but it doesn't help.

Does your probe have its own meter or does it plug in to your multi-meter?



I have to plug my probe into my meter. It may not be the worlds most reliable reading.

Thanks for the reassuring words on X-ray emissions. It kind of got me nervous when the last 1X2 I picked up had a warning painted right on the side of it about X-Rays.

...I stopped at my local antique electronic shop (sorry just couldn't bring myself to go to Radio Shack) and get myself a handful of resistors.
While i share your disgustipation with RS on several levels, in many places they remain the only walk-in source of small parts like resistors, caps, fuses etc. ever since local parts houses went the way of the dodo bird. I grudgingly have to patronize RS pretty regularly. oc

Check all the tubes in the if section and clean all the pins on the tubes in the if.
I'd extend that advice to all of the tubes. The first thing I do in every project (well, first after brushing away the dust) is to clean & test all tubes, as well as all controls & switches.

I remember the CTC-11's service switch well, and that's one reason why I've become eager to clean everything early. After recapping, the set worked very well except for one weird symptom. It was magically cured when Bill asked whether I had cleaned the service switch!

Phil Nelson

I'd extend that advice to all of the tubes. The first thing I do in every project (well, first after brushing away the dust) is to clean & test all tubes, as well as all controls & switches.
Phil Nelson

I'll get a brush and some contact cleaner going on all the tubes next time I have TV time. My rule is also test tubes first, it's just too bad it took me until post #115 to learn that this time around.

Did a good cleaning of all of the tubes today. I also did a good scrubbing of the tuner. I tried moving the horizontal hold in both directions to the maximum. I also changed the channel on the tuner. All of which provided no video. The brightness control works and if I turn it up to maximum I have enough output to see through a phone book I think, the contrast has a very very minimum effect. I was wondering and wanted to ask all of you here is there some test I can run to verify the tuner itself is working versus the if stage not working? Another step I took while working on the underside of the set was to clean up some of my previous work. I decided that I would not accept the level of work I did on this set on future sets so why not start having that work ethic now.

Before:
http://farm6.static.flickr.com/5230/5700769569_4bc06bb603.jpg
After:
http://farm7.static.flickr.com/6121/5923940126_7aea4dbc8d.jpg

One other note, I hooked up the speaker to the set and I am also not getting sound output. I do get a very low hum that increases with the set brightness. Can some one tell me what the term for this is called?

Well first off, does your version of the set have the 'color' switch? If so, what happens when you click the switch back and forth? And does yours have the TV-phono switch? If so, what happens with the sound if you click this switch between TV/phono?

On the hum thingy with brightness, try turning the vert. hold from stop to stop. Does the hum change frequency ('pitch') or remain constant? If it remains constant, this tells you it's not vert. sweep bleed-through. oc

Well first off, does your version of the set have the 'color' switch? If so, what happens when you click the switch back and forth? And does yours have the TV-phono switch? If so, what happens with the sound if you click this switch between TV/phono?

Sorry should have mentioned that there is no color switch. I did clean the crap out of the TV/Phono switch. The is no difference in sound when I turn the TV/Phono switch back and forth, the raster just disappears.

Hokay, how about checking the video detector diode (M4). While you got one end clipped loose, turn the set on and with a clip lead, intermittently short the grid of the 12AU7 1st video stage (V6) pin 2 to ground. Try this with the contrast control at both ends of its rotation. If the two video amp stages are working, there should be some very robust flashing of the raster.

Do what OC suggested first... If a no go, Then you may not be getting b+ voltage to the tuner or the IF circuits. Check and see if the B+ is going into the tuner first and then check for correct voltage at the IF tubes. Look for open resistors in the power supply and the tuner / IF circuits... Be careful!!! The B+ power supply voltage is more dangerous than the high voltage due to the higher current in the B+ power supply.

That's what I've been thinking too - B+ isn't getting to part of the set. Less current draw would account for excessive voltage in the parts that are getting power.

Y'know, the term "B plus" might be a little esoteric to a total Noob unless some background wuz provided on how the term came to be. Looks like he's hopelessly addicted to vintage TVs:D, and the term is gonna be ubiquitous to the addiction.
Anyhow, it harks back to the early days of radio, when radios ran on batteries. The tube filaments ran off a low voltage battery called the 'A' battery. The plates were supplied by a higher voltage source of 90V or more, called the 'B' battery. As radios evolved to run on house current, the plate source continued to be called the 'B' supply, and since it was of positive polarity, simply "B+". And the convention carried on into television practice.

You know that your power supply is working somewhat, since you have a raster on the screen and full vertical & horizontal deflection. To put roundscreen's suggestion another way, it would be useful to find out if the right voltages are being supplied to other parts of the TV (such as IF sections). The 200-something voltage supply is often called "B+," as Bill says.

If you look at your basic power supply, it delivers two such voltages, +255vdc and +210vdc:

http://antiqueradio.org/art/temp/Majestic1600PS.jpg

If you look around the full schematic, there are a number of spots where a little arrow from a section points to either +255vdc or +210vdc.

http://antiqueradio.org/art/temp/Majestic1600A.jpg
http://antiqueradio.org/art/temp/Majestic1600.jpg

The arrow means that a particular circuit draws from that part of the power supply.

If you want to be very systematic, you could start from the ground up, first checking to see if those two voltages are present at the two output points from the basic power supply. (I'm guessing the answer is Yes, else you wouldn't have a full raster.)

Next, you could go around the schematic, checking each place where you see the little arrow to one of those supplies. If you find the right voltages at every spot, that's great! Power is reaching all of those main take-off points.

Finally, you could go to page 8 of the Sams manual, which has the voltage chart, and zero in on the voltages for each tube.

The highest voltage usually goes to the tube's plate. On V14, for instance, that is pin 3.

Since the video IF was suggested, you can check the video IF tubes: V3-V4-V5. On those tubes, the highest voltage is at pin 5 (also 6). For the video section, this will answer roundscreen's question whether the correct B+ voltage is getting to those tubes. For the audio section, the IF tube is V8 and its plate is also pin 5.

Voltage checking is tedious and you must be careful to avoid shocks. Put one hand in your pocket when touching the voltmeter probe to any point in the live chassis.

In the old days, a repair shop would have a set of "tube extenders" that plug between the tube and the chassis, exposing test points for each pin above the chassis. If you don't have tube extenders, you can set the chassis on its side and measure from underneath. If neither of those is possible, you can wrap a short piece of wire around the pin in question, re-insert the tube, and measure from that wire (slip a bit of plastic or paper between the wire and the chassis to avoid a short circuit).

An experienced repairman with a shop full of specialized equipment (signal tracer, oscilloscope, etc.) could isolate your problems much more quickly, but if you're armed with nothing but a multimeter, this slow approach can be useful.

Read the little notes below the voltage chart before you start, and note the line voltage setting (often 117vac). For initial checks like this, I want to see whether a voltage is in the right ballpark. If the chart says 105vdc and I measure, say, 93vdc or 111vdc, I figure that's close enough for the tube to basically operate, and I move on to the next one.

Sometimes, a bad reading will jump out at you, and then you can look for a burned resistor, miswired component, etc., in that tube's circuit.

If you go through all of these measurements and don't find any bad readings, you have not wasted your time. It's useful to know all of the places where your TV does have correct voltages, and that would confirm that a lot of your recapping work was successful.

If measuring voltages on the live chassis isn't practical, for whatever reason, you could fall back on the resistance chart, measuring resistances on the same pins. I normally do this from under the chassis, with the tubes in place.

Sorry for the long-winded reply. This is my way of avoiding work on my Capehart set, where I'm unearthing ugliness like a burned-up width control :)

Phil Nelson

Hey that's a nice tutorial, Phil.:)
There is another 'esoteric' feature that'll inevitably be encountered that may be a puzzlement to a Noob. And that is the 'B boost' or 'bootstrap' voltage generated by the damper tube's operation. It's a by-product of that diode's anti-ringing action, and appears as rectified DC that's stacked or 'bootstrapped' on top of the regular B+ supply. Hence it's called 'B boost'.

When filtered, it turned out to be quite fortuitous and handy in supplying higher voltages for certain applications. One is the plate circuit of the vert. oscillator, enabling it to make a nice linear, high level sawtooth. Another is the high level audio detector (with the quad coil) used in Zeniths, which enables the detector to drive the output stage directly, eliminating need for a 1st audio stage.

(In vts1134's set, the B boost is delivered to the low end of the vert. size control. And it also supplies grid 2 of the CRT.)

Thank you for the explicit explanation Phil. I've started to go over the set from the beginning, starting at T1.


http://antiqueradio.org/art/temp/Majestic1600PS.jpg
Phil Nelson

In the schematic above "x" refers to the 6.3vac heater. It comes out of T1 with another line that is connected to ground. What I have noticed is that BOTH leads are connected to ground. My question is should "x" be connected to ground?

Hokay, how about checking the video detector diode (M4). While you got one end clipped loose, turn the set on and with a clip lead, intermittently short the grid of the 12AU7 1st video stage (V6) pin 2 to ground. Try this with the contrast control at both ends of its rotation. If the two video amp stages are working, there should be some very robust flashing of the raster.

Following this test gave me no no changes in the raster at all on either end of the contrast adjustment.

...In the schematic above "x" refers to the 6.3vac heater. It comes out of T1 with another line that is connected to ground. What I have noticed is that BOTH leads are connected to ground. My question is should "x" be connected to ground?
It looks like there are two leads coming out of T1 that go to ground. One is the centertap of the Hv secondary, and the other is the bottom end of the 6.3V secondary (the heater winding). The top of the 6.3V winding is point 'X', and it certainly should not be grounded.

Following this test gave me no changes in the raster at all on either end of the contrast adjustment.
Doggone. Now this may sound like a dumb question, but are the heaters in the 12AU7 video amp tube (V6) lighting up? It has two heaters. For that matter, are there any other tubes in the chassis (other than the 1X2) that are not lighting up? In know, dumb question but it has happened to me more than once. Chased a problem around in circles and it was a cold heater all the time. :o:eek:

It looks like there are two leads coming out of T1 that go to ground. One is the centertap of the Hv secondary, and the other is the bottom end of the 6.3V secondary (the heater winding). The top of the 6.3V winding is point 'X', and it certainly should not be grounded.

There are eight leads coming out of T1. I account for all of them, and unless I am reading something wrong ALL of my heaters and the "x" lead out of T1 are shorted to ground. The "x" lead from the transformer goes to a terminal strip and is soldered to three leads that run to the heater pins. When I disconnect those leads from each other every one of them reads shorted to ground including the lead from T1.

http://farm7.static.flickr.com/6004/5948089667_444d68b453.jpg

I'm pointing to the location where the leads were soldered together in the picture above. The terminal the right is where the proper ground lead runs to, it's terminal is connected directly to the chassis.
Does that make any sense at all?

For most tubes, one of the filament pins will be connected to the heater source and the other filament pin will connect to ground.

In the full schematic, for instance, look at the video IF amps, V3-V4-V5. For each of them, pin 4 connects to the X filament source and pin 3 connects to ground.

http://antiqueradio.org/art/temp/Majestic1600A.jpg

So, what I would expect to find is a line running from the X source to each of the pin 4s on those tubes. A filament presents only a few ohms resistance, so if you disconnect the X line from a tube socket and leave the tube in place, that might be mistaken for a short circuit. If you remove that tube from the socket while the X line is disconnected from pin 4, it should show infinite resistance.

I don't know if that clears things up or makes them more confusing . . . .

Phil Nelson

...unless I am reading something wrong ALL of my heaters and the "x" lead out of T1 are shorted to ground. The "x" lead from the transformer goes to a terminal strip and is soldered to three leads that run to the heater pins. When I disconnect those leads from each other every one of them reads shorted to ground including the lead from T1.
OK, here's what's going on: you're reading DC resistances so low that they show 'short' on your meter. All those tube heaters in parallel will show very low DC resistance, as will the 6.3V winding. But rest assured there is no short. If there were the tube heaters would not be lighting, and the 3 amp line fuse would blow.

Now on that 12AU7 video tube (V6), both heaters are lighting, right?

At the risk of seeming an intransigent fuddyduddy:eek:, i'd like to take the occasion to air a little sumpthin'. That's regarding usage of the terms "heater" and "filament". Back in the day, it was quite a big deal to use those terms correctly. :boring:Any tube with an indirectly heated cathode uses a heater, not 'filament'. Any tube not using an indirectly heated cathode (eg., 5U4, 1B3, 1X2, 1R5, 80, 26, etc.) uses a filament, as in a light bulb.
Any techie using the terms incorrectly would come under severe admonition and demerit.:blah:

At the risk of seeming an intransigent fuddyduddy:eek:, i'd like to take the occasion to air a little sumpthin'. That's regarding usage of the terms "heater" and "filament". Back in the day, it was quite a big deal to use those terms correctly. :boring:Any tube with an indirectly heated cathode uses a heater, not 'filament'. Any tube not using an indirectly heated cathode (eg., 5U4, 1B3, 1X2, 1R5, 80, 26, etc.) uses a filament, as in a light bulb.
Any techie using the terms incorrectly would come under severe admonition and demerit.:blah:

A-hem... Mah tubes use glow plugs, you insensitive clod! (:D)

Anyhoo, just checking in with the progress so far, looks like you got quite a bit further since I last posted. (haven't posted since then since others know more about the specifics than I do)... Still got my fingers crossed for you!

I've taken a couple of weeks off from the set because I thought it was getting a little frantic. I've found that learning how to work on vintage tube electronics completely from an internet forum having no prior knowledge of the subject is quite an undertaking. I could not have asked for more knowledgeable and patient mentors and I think all of you for the efforts you have put through my hands. After two weeks of time away from the "bench" I am missing my TV time. Since starting this new obsession I've only worked on the Mighty Monarch and the radio half of an RCA 730TV1. I'd like your opinions, should I make another push on the Monarch or would it be okay to put it on hold for a bit more and start on the TV side of the 730TV1?

You gotta finish it! Don't leave us hanging, baby! :)

Seriously though, I have had to put things away and look at them fresh another day. Just do whatever feels right, and keeps you from being too overwhelmed.

I obsessed over one project until it infuriated me and it ended up scrapped. Don't let that happen to you ;)

I try to tackle one (occaisionally two) projects at a time so my work space does not get too cramped. The two is for when I'm dying to work on something or when the stuff is small or easy.

That said you should do what you think is best/most fun.

Tom C.

Decided on a second push with the Monarch. I performed OC's test on the video stage mentioned in post #267 again just to make sure I was doing it correctly.
http://farm7.static.flickr.com/6006/6019512031_cdeffa9b5a.jpg
You can see M4 disconnected in the upper right hand corner of the picture and the clip lead on pin 2 of the 12AU7 towards the middle.
The test produced no results.

Doggone. Now this may sound like a dumb question, but are the heaters in the 12AU7 video amp tube (V6) lighting up? It has two heaters. For that matter, are there any other tubes in the chassis (other than the 1X2) that are not lighting up? In know, dumb question but it has happened to me more than once. Chased a problem around in circles and it was a cold heater all the time. :o:eek:

http://farm7.static.flickr.com/6025/6020063642_2ea889e956.jpg
This is a picture of the 12AU7, lit up like a Christmas Tree. All other tubes in the set are also lit.

I've also checked the voltages on several of the tubes including all of the video section. What I've noticed is that with my input voltage at 117vac my B+ is running around 15% high across the set, but it is getting to the correct pins. I have not checked the voltages on the tuner tubes. Measuring them from the bottom of the set is impossible so I will need to acquire some extenders.

I'm going to bring some new tools to the party to help the second push along. I'll have a scope, and a video generator tomorrow. I'm not sure these will help in my current campaign, but they're there if needed.

:wave: I hope all of you who have been helping me along are up for a second push :thmbsp:.

Onward! Hey. :D:rockon: Give a holler when you've got the 'real' test gear in hand. I was gonna suggest the 'quick & dirty' method of signal injection using the 6V heater supply like you did earlier for the vertical. But with a proper signal genny you can attenuate the level as you work back stage by stage.

Since you've verified the plate voltages on the 12AU7, have you checked the three peaking coils (L10, L11, L12) for continuity? And how about the detector diode? What's its forward/reverse readings on the ohmeter? Not shorted is it?
oc

Onward! Hey. :D:rockon: Give a holler when you've got the 'real' test gear in hand. I was gonna suggest the 'quick & dirty' method of signal injection using the 6V heater supply like you did earlier for the vertical. But with a proper signal genny you can attenuate the level as you work back stage by stage.

Since you've verified the plate voltages on the 12AU7, have you checked the three peaking coils (L10, L11, L12) for continuity? And how about the detector diode? What's its forward/reverse readings on the ohmeter? Not shorted is it?
oc

The heavy hitter test gear will take a few days. I have to order a probe for the scope.
The peaking coils L10-13 all read at or close to spec. The diode reads .3v drop across it.
One thing I did notice after reading all of the voltages on the video stage tubes again. Pin 7 on the 12AU7 was the only voltage that was a good bit off of spec. It is supposed to read -.2vdc, it actually reads -.57.

If you have the video testpattern generator, then you can test it by connecting the video out leads to the video input jack on a modern TV.

If the video generator works the next thing I'd do is connect it to the side of the video detector diode in the monarch that feeds the video amp(s) and see if you get video.
If you do then concentrate your search on everything between and including the antenna terminals and the detector. If you don't get video then focus on every thing between the detector diode and the CRT.

Hope this helps.

Tom C.

The heavy hitter test gear will take a few days. I have to order a probe for the scope.
Well, while waiting for the heavy artillery, if you're game to try the 'quick & dirty' method of signal injection, here's how i would do it -
Tie onto the 6.3V heater supply just like you did earlier for the vertical, except this time put a cap in series with the clip lead. Value isn't critical, anywhere from .01 to .1 is OK. This'll give you a DC-isolated 60 cycle signal for injection.
Start at G1 of the CRT (pin 2). The raster should show a mild hum bar. Now hit the plate of the video output stage (pin 6 of the 12AU7). The same hum bar should appear. Now hit the grid (pin 7). The hum bar should show quite a bit of amplitude gain. Now hit the plate of the 1st video stage (pin 1 of the 12AU7). It should show the same amplitude gain.

Now to inject at the grid of the first video stage, it's a good idea to attenuate the signal so as to not overdrive the video stages. So let's utilize the 8.2K resistor (R27) that's already in place between the grid (pin 2) and ground. Add an 82K resistor in series with the cap on your clip lead, so that this new resistor is now the "probe". When touched to the grid (pin 2), it's also in series with R27 and forms a voltage divider giving a little over 10X attenuation. So the grid will be seeing about .59 VAC of signal. Of course you can reduce the value of the new resistor to give less attenuation if desired. {Those two coils L10 and L11 can be considered zero ohms in this situation.}

As a precaution, i would leave the diode M4 disconnected during the procedure.

So if you lose the signal at any point while working back stage by stage, that will isolate where the failure is at.
Pin 7 on the 12AU7 was the only voltage that was a good bit off of spec. It is supposed to read -.2vdc, it actually reads -.57.
That doesn't mean anything since that's a very high impedance point, and the original meter probably loaded it more than the new meter you're using.
oc

If you have the video testpattern generator, then you can test it by connecting the video out leads to the video input jack on a modern TV.

If the video generator works the next thing I'd do is connect it to the side of the video detector diode in the monarch that feeds the video amp(s) and see if you get video.


Question.
Make the connection pre diode, or post diode?

Question.
Make the connection pre diode, or post diode?
Ya might wanta ask- what is the function of the diode? :)

:) what is the function of the diode:)?
Also if I'm asking, what is the function of a peaking coil?

:) what is the function of the diode:)?
Well, since the amplitude-modulated IF signal (actually a radio-frequency AM signal) is going into the diode, what is the diode doing to it? Hint- what is a power supply rectifier doing to the AC from the powerline?

Well, since the amplitude-modulated IF signal (actually a radio-frequency AM signal) is going into the diode, what is the diode doing to it? Hint- what is a power supply rectifier doing to the AC from the powerline?

Converting it from IF to a video signal :headscrat? So if I connected the generator pre-diode it would be feeding the wrong signal into it. I would need an IF generator to test pre-diode.
The rectifier converts AC to DC?

Converting it from IF to a video signal :headscrat? So if I connected the generator pre-diode it would be feeding the wrong signal into it. I would need an IF generator to test pre-diode.
The rectifier converts AC to DC?
BINGO on all counts. :beerchug:

On your question about peaking coils, they 'tailor' the high-frequency (aka fine detail) component of the video signal.

Well, while waiting for the heavy artillery, if you're game to try the 'quick & dirty' method of signal injection, here's how i would do it -
Tie onto the 6.3V heater supply just like you did earlier for the vertical, except this time put a cap in series with the clip lead. Value isn't critical, anywhere from .01 to .1 is OK. This'll give you a DC-isolated 60 cycle signal for injection.
Start at G1 of the CRT (pin 2). The raster should show a mild hum bar. Now hit the plate of the video output stage (pin 6 of the 12AU7). The same hum bar should appear. Now hit the grid (pin 7). The hum bar should show quite a bit of amplitude gain. Now hit the plate of the 1st video stage (pin 1 of the 12AU7). It should show the same amplitude gain.

Now to inject at the grid of the first video stage, it's a good idea to attenuate the signal so as to not overdrive the video stages. So let's utilize the 8.2K resistor (R27) that's already in place between the grid (pin 2) and ground. Add an 82K resistor in series with the cap on your clip lead, so that this new resistor is now the "probe". When touched to the grid (pin 2), it's also in series with R27 and forms a voltage divider giving a little over 10X attenuation. So the grid will be seeing about .59 VAC of signal. Of course you can reduce the value of the new resistor to give less attenuation if desired. {Those two coils L10 and L11 can be considered zero ohms in this situation.}

As a precaution, i would leave the diode M4 disconnected during the procedure.

So if you lose the signal at any point while working back stage by stage, that will isolate where the failure is at.

oc

Can I use the signal generator for all of the above steps? Starting with G1 of the CRT and working back to the detector diode. I'm guessing that anything after the video amp will not give me anything like a picture, but should give me some change in the raster, and anything before the video amp (assuming the failure is upstream) will give me the full pattern. Am I right?

Can I use the signal generator for all of the above steps?
Sure, absolutely.
Starting with G1 of the CRT and working back to the detector diode. I'm guessing that anything after the video amp will not give me anything like a picture, but should give me some change in the raster, and anything before the video amp (assuming the failure is upstream) will give me the full pattern. Am I right?
Well, when you hit G1 of the CRT (with the genny's output set high enough to see the signal), you should see whatever pattern the genny is set to. It might be negative though (that is, just like a photonegative). As you work back, you should see gain when you hit the grid of the video output stage (pin 7), and attenuating the genny as as needed, more gain at the grid of the 1st video stage (pin 2). This'll confirm that the video stages are working.
As mentioned before, since the detector diode is so easy to get to, i would leave it disconnected as a precaution against zapping it with the probe.

You'll probably see the pattern phase-invert (ie., shift from negative-to-positive) as you work back. That's because a tube's plate is 180 degrees out of phase from the grid. Grid goes positive, tube conducts more, pulling plate voltage down. Grid goes negative, tube conducts less, allowing plate voltage to rise.
oc

Sure, absolutely.

Well, when you hit G1 of the CRT (with the genny's output set high enough to see the signal), you should see whatever pattern the genny is set to. It might be negative though (that is, just like a photonegative). As you work back, you should see gain when you hit the grid of the video output stage (pin 7), and attenuating the genny as as needed, more gain at the grid of the 1st video stage (pin 2). This'll confirm that the video stages are working.
As mentioned before, since the detector diode is so easy to get to, i would leave it disconnected as a precaution against zapping it with the probe.

You'll probably see the pattern phase-invert (ie., shift from negative-to-positive) as you work back. That's because a tube's plate is 180 degrees out of phase from the grid. Grid goes positive, tube conducts more, pulling plate voltage down. Grid goes negative, tube conducts less, allowing plate voltage to rise.
oc

When I inject video directly on pin two of the crt I am getting nothing more than the slightest change in raster. There is definitely not any sign of the pattern that the generator is outputting. There is control for phase +/-, adjusting this gives slight changes in the raster. When that control is left in the 12 oclock position there is no change in the raster from the generator in the off position.
I am using a piece of wire wrapped around pin 2 of the crt to attach my video output test lead to, and the negative test lead I'm attaching to the chassis.
I've also hooked up the generator to my living room tv's composite input and verified that the generator is in fact outputting a signal.

Is there some other way to verify that the crt is ok?
Could the signal be too high or low coming out of my generator to give a full picture when connected directly to pin 2 of the crt?
Will there be a party when this is all over that every one is invited to?

I can only answer the third one:thmbsp:.

When I inject video directly on pin two of the crt I am getting nothing more than the slightest change in raster. There is definitely not any sign of the pattern that the generator is outputting. There is control for phase +/-, adjusting this gives slight changes in the raster. When that control is left in the 12 oclock position there is no change in the raster from the generator in the off position.
I am using a piece of wire wrapped around pin 2 of the crt to attach my video output test lead to, and the negative test lead I'm attaching to the chassis.
I've also hooked up the generator to my living room tv's composite input and verified that the generator is in fact outputting a signal.
:sadwave: What about if you inject at pin# 7, the grid of the vid.out stage?
Is there some other way to verify that the crt is ok?
The jug appears to be OK if you're getting a decent raster and the brightness control works as it should.
Could the signal be too high or low coming out of my generator to give a full picture when connected directly to pin 2 of the crt?
Too low, maybe. Too high not likely at all.
Will there be a party when this is all over that every one is invited to?

I'll bring the beer. :D

:sadwave: What about if you inject at pin# 7, the grid of the vid.out stage?


Ok, here is the worlds worst youtube video :no:.
http://www.youtube.com/watch?v=wqO0pCZS8gU
I used two different patterns. The first was one horizontal line, the second was one vertical line. I adjusted the phase from all the way positive to all the way negative on both patterns. Please forgive the angle of the camera.

So what happens if you inject at pin 2, the grid of the 1st video stage (with the diode disconnected)?
Have you actually checked the diode with an ohmeter? It's a very elderly germanium diode, and should show a very high (though probably not infinite) resistance in one direction and a much lower resistance in the other direction.

So what happens if you inject at pin 2, the grid of the 1st video stage (with the diode disconnected)?
Have you actually checked the diode with an ohmeter? It's a very elderly germanium diode, and should show a very high (though probably not infinite) resistance in one direction and a much lower resistance in the other direction.

The diode reads 35k in one direction and 1.5k in the other.
There is no change in raster when I inject at pin 2 of the 12au7.

The diode reads 35k in one direction and 1.5k in the other.
There is no change in raster when I inject at pin 2 of the 12au7.
OK, so what happens if you inject at the plate of the 1st video stage (pin1)? It should show the same pattern and same amplitude as at pin 7 (grid of output stage).
There's a coupling cap, C28, which goes from peaking coil L12 to pin 7. Could this cap possibly be misconnected?

The reverse reading on the diode seems a little wonky to me, though that's not germaine to the issue at hand. When you get the video stages working, it might be a good idea to replace the diode on general principles. A second opinion on that from resident mavens would be appreciated.
oc

I'll be damned if you weren't right about C28, the coupling cap. I had that screwed up :dammit::withstpd:. Pin 1 and 2 now give a change in raster when I inject there.
The picture below shows what the three vertical line pattern looks like on the screen.
http://farm7.static.flickr.com/6149/6036213489_eaa38f8f22.jpg
You can see where the three lines are drawn on the screen, although they are distorted. Is there adjustments on the set that I can use to try and dial the picture in? The video is being injected just aft of the disconnected M4 btw.

Try tweaking the horizontal and vertical hold controls. You will need to become familiar with adjusting those controls anyway.

I'll be damned if you weren't right about C28, the coupling cap. I had that screwed up :dammit::withstpd:. Pin 1 and 2 now give a change in raster when I inject there.
WooHoo!:sing: So was C28 connected to the wrong pin or somethin'? Does the contrast control now work? For the heck of it, might as well reconnect the diode and see if anything's coming through the IFs. But be sure and keep your needlenose clamped on the diode's lead as a heatsink until the joint cools. Such an ancient diode may be prone to heat damage.
oc

Heat can fix them to I have a Zenith that had no video and almost no sound. Unsoldering and resoldering the detector diode fixed it.

WooHoo!:sing: So was C28 connected to the wrong pin or somethin'? Does the contrast control now work? For the heck of it, might as well reconnect the diode and see if anything's coming through the IFs. But be sure and keep your needlenose clamped on the diode's lead as a heatsink until the joint cools. Such an ancient diode may be prone to heat damage.
oc

I think the contrast control might be bad. When I rotate it in one direction it becomes shorted to ground. Adjusting the control does not give me similar contrast adjustment in the raster. If I adjust the control quickly the raster sort of flashes briefly and then goes back to the original level. I've previously cleaned the control with contact cleaner and the knob rotates freely. Is it possible to temporarily use a normal 1500ohm resistor in it's place for testing purposes?

I'd dismantle the control and go at it with an old toothbrush and contact cleaner as it sounds like it has tin wiskers.

I think the contrast control might be bad. When I rotate it in one direction it becomes shorted to ground. Adjusting the control does not give me similar contrast adjustment in the raster. If I adjust the control quickly the raster sort of flashes briefly and then goes back to the original level. I've previously cleaned the control with contact cleaner and the knob rotates freely.
If you put an ohmeter on the control, from the wiper to the 'top' end (which goes to pin 3 of the 12AU7) and rotate the control, the meter should reveal any rough spots or drop-outs. An analog meter is preferable as its needle will follow the control's rotation, while a digital meter just gives a bunch of hard to follow jumping digits.
Is it possible to temporarily use a normal 1500ohm resistor in it's place for testing purposes?
Actually the resistor will give you minimum gain (contrast), while shorting the 'top' end of the control directly to ground will give maximum gain.
oc

If you put an ohmeter on the control, from the wiper to the 'top' end (which goes to pin 3 of the 12AU7) and rotate the control, the meter should reveal any rough spots or drop-outs. An analog meter is preferable as its needle will follow the control's rotation, while a digital meter just gives a bunch of hard to follow jumping digits.

Actually the resistor will give you minimum gain (contrast), while shorting the 'top' end of the control directly to ground will give maximum gain.
oc

Sorry, I didn't look at the schematics close enough. The top end of the control SHOULD have low impedance to ground.

The anticipation at the Estep house is building!!!
It's getting closer, so closer!!!
http://www.youtube.com/watch?v=XBa9o5VnNIY
The video is being fed from a VHS tape of Grease, one of my wife's favorite movies.

Say hey!:banana: Try the fine tuning. When you get some recognizable video, try the horiz. hold as the horiz. frequency looks to be quite a ways off. What does the raster do now when you turn the contrast control stop-to-stop?
Mayhaps some kindly soul will post the left-hand side of the schematic. It's hard to tell if there might be some kind of AGC control there or not.
oc

I think the horizontal is seriously off. I'm sniffing around the horizontal osc tube right now. I'm getting some off voltages (even more so than my high across the board on the rest of the set.
Pin 1 should range from -1.8 to -2.5. If I adjust the horizontal afc to get -1.8 on the high side of the horizontal hold then I get -12 on the low side.
Pin 2 should range from 170 to 130. It's ranging from 210 to 125 so that doesn't sound too far off there.
Pin 3 should range 4.3 to -.8. It's ranging from 21 to 5.4.
Pin 4 should be -55. I'm getting a strange reading on this one. My meter keeps jumping from -73 to out of range.
Pin 5 should be 165. I'm getting the same meter behavior on this pin. It's jumping from 186 to out of range.
Pin 8 is the heater. It's spot on 6.3.
What do you thinks happening on pins 4 and 5?
Are the voltage problems on pins 1 and 3 a symptom of my frequency being totally out of whack.
The contrast control does change the raster, buts it's hard to tell how much it changes without a proper picture.

I don't know how to post the schematic short of just taking a picture of it, but I can't get a readable picture. If no one else can post it here then I can try taking several pictures close up to make it readable.

Don't worry about posting the rest of the schematic just yet. Need to get the horiz. sorted out first. Can you adjust B1, the horiz. frequency adjustment? Caution: if it's a powdered iron slug with an internal hole requiring a hex tool (which is doubtful), don't try to adjust it without that tool. If it's a brass screw shaft with a screwdriver slot in the end, you're good to go.

If the adjustment doesn't turn easily, don't force it.

Remember to use a plastic hex tool as not only will a metal one make it harder to adjust right, but it also can crack the slug (and that is quite bad).

.
What do you thinks happening on pins 4 and 5?

Pins 4 and 5 are the grid and plate of the oscillator, respectively. They carry a high level, complex waveform which causes a digital meter to go nuts. The voltages are probably OK since the oscillator is obviously running very robustly.

The horizontal afc is a easily adjustable. This is what I adjusted to get the high side of pin 1 to -1.8. I can adjust it from end to end without any problems (it's a screw tip btw). I cannot seem to lock in the picture no matter where it is though. I am adjusting it in conjunction with the horizontal hold control. I traced most of the capacitors that I replaced in that area and couldn't find one I missed, or misplaced. I'll try to get to the rest of them today. Is there another method to use with the horizontal afc besides turn it until you get a picture?

I believe that the AFC tries its darnedest to keep the horiz in synch when it is slightly off frequency. However if it is badly off frequency the AFC can try as hard as it likes and will still fail to make the horizontal sync up. I think you will get better results adjusting the horizontal frequency rather than the AFC.

The horizontal afc is a easily adjustable. This is what I adjusted to get the high side of pin 1 to -1.8. I can adjust it from end to end without any problems (it's a screw tip btw). I cannot seem to lock in the picture no matter where it is though. I am adjusting it in conjunction with the horizontal hold control. I traced most of the capacitors that I replaced in that area and couldn't find one I missed, or misplaced. I'll try to get to the rest of them today. Is there another method to use with the horizontal afc besides turn it until you get a picture?
First off, don't be too concerned with the voltage readings on pins 1 and 3. They are at very high impedance, and your meter puts lighter loading on the circuit than the original meter did. Thus you get higher readings than the original meter gave.
In your last vid, it sure looks like the fine tuning adjustment is off. That's the outer shaft concentric to the channel selector shaft. Have you tried turning that stop-to-stop? Once the signal is tuned in properly, it'll be a lot easier to see what's going on with the horizontal.

What channel are you using to feed the signal to the set? Just on the chance that the tuner's tracking might be off, try clicking one channel higher and one channel lower, and fine tune stop-to-stop, and see if you can see a recognizable pattern (even with the horiz. frequency still off).

I believe that the AFC tries its darnedest to keep the horiz in synch when it is slightly off frequency. However if it is badly off frequency the AFC can try as hard as it likes and will still fail to make the horizontal sync up. I think you will get better results adjusting the horizontal frequency rather than the AFC.

I thought that the Horizontal AFC was the horizontal frequency adjustment. Is there another adjustment that I'm missing?
Adjusting fine tuning, horizontal hold, and horizontal afc the picture below is as close as I can get. The pattern should only be three vertical white lines on a black background.
http://farm7.static.flickr.com/6135/6042630805_011819e323.jpg

I thought that the Horizontal AFC was the horizontal frequency adjustment. Is there another adjustment that I'm missing?
Adjusting fine tuning, horizontal hold, and horizontal afc the picture below is as close as I can get. The pattern should only be three vertical white lines on a black background.

Well, AFC stands for "automatic frequency control" which is the function of the first section of the tube (the second section being the oscillator). The AFC section takes the sync signal and compares it to the oscillator's signal and then automatically adjusts the oscillator up or down to lock it to the sync signal. (The 'horiz. hold' control {R7} adjusts the locking range of the AFC).
Anyhow, the oscillator should be running at 15.75khz. If the oscillator is 'waay off but running at some integer of 15.75khz, the AFC section can lock onto that. And that's apparently what's happening.
It's hard to tell from that screen photo if the osc. is running above or below the correct frequency. The oscillator's frequency adjustment is that coil B1. Adjusting B1 should bring the osc. to the correct frequency unless something's seriously out of whack.

So B1 IS the afc and adjusting it adjusts the horizontal frequency?

So B1 IS the afc and adjusting it adjusts the horizontal frequency?
B1 adjusts the oscillator's frequency.

B1 is not the AFC.

The term AFC (automatic frequency control) is a bit misleading as it's used here, because it does not control frequency; it controls locking action, locking the oscillator to the incoming sync signal once the oscillator is close enough to be "grabbed" and locked in. A better term might be "automatic lock control" or "automatic hold control".

As mentioned before, the oscillator can be running at an entirely different frequency and still be grabbed and locked to the sync signal, which appears to be the case in that last screen shot.

A bit misleading indeed. At any rate, the last picture I posted was as close as I could get through adjusting B1. Something else must be outa whack. I've checked the connections in and around the horizontal oscillator and sync tubes, nothing jumped out as misconnected or wrong. I also swapped out the horizontal oscillator tube for good measure.
So close yet so far.

What about the 8.2K resistor (R81) which parallels the B1 coil? Have you verified its value? And the 330pf cap (C57)? Could it possibly have been replaced with a different value?

Any chance you could post a vid of the screen while turning the B1 adjustment all the way in and out, while narrating what you're doing? This might give a better handle on whether the osc. is running too high or too low.

BTW, you're also trying the horiz. hold control (R7) along with the B1 adjustments, right?

Does the genny's three-stripe pattern display correctly on another TV?
Or better yet, can you feed the Majestic with actual program material from something like a DVD player or a VCR?

R81's value is on target.
I've got the video below. It starts with the slug all of the way "out." I found that I could adjust the slug a bit more after the end of the video and when I did the picture looked a lot like it did in the beginning of the video.
http://www.youtube.com/watch?v=74tfWbkOgH0
Just out of curiosity, for those of us without super human horizontal frequency identification vision. Would measuring the frequency of the oscillator be something I could use a scope for? I don't have my probe yet so I couldn't do it now, but it sure seems like that'd be something I'd use it for in the future.

R81's value is on target.
I've got the video below. It starts with the slug all of the way "out." I found that I could adjust the slug a bit more after the end of the video and when I did the picture looked a lot like it did in the beginning of the video.
http://www.youtube.com/watch?v=74tfWbkOgH0
It looks to be spot-on at :02-:06, :09-:13, :19-:21, :26-:30, and :35-:37 in the vid. Set B1 back to where you had it there. There appears to be nothing wrong with the horiz. frequency. But the fine tuning is still off. The set wants to make a picture when the signal is tuned in properly. Are you turning the fine tuning stop-to-stop? On the chance the tuner's tracking might be off, click the channel selector to the next higher channel and try the F.T. stop-to-stop. Then try the same thing one channel lower. If the VCR is outputting on Ch.3, try it on Ch.4 (or vice versa).
The vert. hold is also gonna need adjusting when the pic is tuned in.
Yer aaaalmost there. :D:D
oc

I've tried fine tuning the signal as much as I can and I still can't get it any better. I changed the output of the VCR from channel 3 to 4. When I changed channels up and down away from the modulated channel I noticed that when I was one channel lower I got strong audio but not picture. One channel higher gave me neither sound nor picture. Maybe I'll take the tuner apart and give it a good cleaning. I did notice some things tonight that I thought I'd share. The set can only lock onto a picture when the horizontal frequency slug is 1/8 of a turn from completely out or 1/8 of a turn from completely in. When it is in that position, although the picture locks on, the horizontal does not fill the screen. I removed the resistors we had in place on the horizontal output tube to reduce voltage to the 1X2 to see if that would A. bring the picture back to full horizontal and B. cause the 1X2 to spark again now that the frequency was so different. It did succeed in making the horizontal size increase somewhat, although not back to full screen. The set is now also back on full line voltage without the additional resistors on the horizontal output tube and there is no sparking problem in the 1X2. I also went back to the video generator to see if I could get the set to lock on to a pattern now that the horizontal frequency is where it wants it to be. I injected at the point where M4 would connect. After much adjustment the picture below is the best that I could tune it in.
http://farm7.static.flickr.com/6210/6050827921_4eacb95f3e.jpg

Looks good on the horizontal synch/frequency front, but the vertical probably needs some work.
I'd say you're within spittin distance of getting a watchable picture.

Much improved. If you clean the tuner, resist the temptation to hose the whole thing down with spray cleaner. My favorite method is to dip Q-tips into liquid DeOxit (just spray some in a little cup) and then rub the contacts, working the tuner back and forth once something is wetted.

You probably can't reach everything with Q-tips, and may have to spray some, but you get the idea: Less is more. If it's a wafer type tuner, I'd avoid soaking the phenolic wafers more than necessary. Dab up any excess with paper towel or a soft cloth, and allow ample time for it to dry out (maybe even overnight) before powering up again.

Don't use anything abrasive. If contacts are plated with precious metal, you don't want to scrub that off.

Phil Nelson

Just curious- is the fine tuning actually working? Do you see a change in the display when you adjust it? If not, the F.T. mechanism might be busted.

The tuner is a turret style tuner. I did remove it once before and cleaned each (bump?) with contact cleaner sprayed onto, and then applied with, a Q-tip. I also used cleaned the contacts in the set the same way. Is there anything inside the turret that would benefit disassembled it and cleaned it with a similar method?
The fine tuning does affect the picture. It's kind of hard to describe but it's almost like there is two pictures one on top of the other. The "top" picture has some wavy lines that go from the top of the screen to the bottom. Then there is the "bottom" picture which is the signal from the VCR. The bottom picture as well as the sound are affected by fine tuning. The sound gets quieter and a bit distorted, and the "bottom" picture gets softer at one end of the fine tuning rotation. The sound gets louder and more crisp and the picture gets sharper at the other end of the ft rotation. I don't think the change in picture would show up in a video as it's pretty tough to see with my own eyes.
I'm going to take a second look at all of the connections (and values) of things in the vertical section to see if I can't find something jumping out at me that might explain the problem towards the top of the screen tonight. If the tuner could benefit from an internal cleaning I'll try to get that done as well. My friend at work gave me a can of Tun-O-Wash so I'll can give that a shot.

Sounds like the fine tuning is working OK. And it's a turret type tuner. And you've probably done an adequate job on the contacts already.

Before you do any more washing, eyeball the front of the tuner for an access hole to the tuner's oscillator adjustment (sometimes called the 'bulls eye' adjustment). Each of the channel strips contains a metal slug which aligns with the hole when clicked to the corresponding channel (eg., when you click to Ch.3, the Ch.3 slug will align with the hole), and you adjust the slug with a non-metalic thin screwdriver to tune in the channel. Do this with the fine tuning at mid range. (Or if the VCR uses Ch.4, do the same with the tuner clicked to Ch.4).

Occasionally one or more of the slugs will be missing due to someone's screwing them all the way out. You should be able to shine a light through the access hole to verify each slug as present, or pop each of the strips outa the turret to visually inspect them and see if any slugs are missing.

Don't worry about the vertical issue until you get the signal tuned in properly.

Be carefull to only have one strip out at a time so you don't mixup the channel order.

Sounds like the fine tuning is working OK. And it's a turret type tuner. And you've probably done an adequate job on the contacts already.

Before you do any more washing, eyeball the front of the tuner for an access hole to the tuner's oscillator adjustment (sometimes called the 'bulls eye' adjustment). Each of the channel strips contains a metal slug which aligns with the hole when clicked to the corresponding channel (eg., when you click to Ch.3, the Ch.3 slug will align with the hole), and you adjust the slug with a non-metalic thin screwdriver to tune in the channel. Do this with the fine tuning at mid range. (Or if the VCR uses Ch.4, do the same with the tuner clicked to Ch.4).

Occasionally one or more of the slugs will be missing due to someone's screwing them all the way out. You should be able to shine a light through the access hole to verify each slug as present, or pop each of the strips outa the turret to visually inspect them and see if any slugs are missing.

Don't worry about the vertical issue until you get the signal tuned in properly.

Sadly this didn't do the trick. Adjusting this tuning slug gave me much the same results that adjusting the ft gave me, except on a much bigger scale. Again the "bottom" picture went from sharp to soft to just static on each direction of the rotation, but all the while seemed to be beneath another picture. The "top" picture had no change at all with either the tuner slug, or the fine tuning adjustment. I will try to take video tomorrow while adjusting ft and the tuning slug to show on video what I am describing.

Well tarnation. Ain't that a kick in the wazoo. From your description it begins to sound like signal overload, like maybe the set's rather primitive AGC (automatic gain control) system is being swamped. What happens if you loose-couple the VCR's signal going into the tuner? That is, just hang the end of the VCR cable close to the leadin without directly connecting it, to reduce the signal strength.

I did this test using the signal generator and the rf output of a vcr. I'll show you pictures of the signal generator because it is much easier to photograph the phenomenon I have tried to describe.
http://farm7.static.flickr.com/6190/6057050671_7881493561.jpg
The picture above is with the generator directly coupled to the rf input on channel 6. The pattern is vertical lines. You can see that the vertical lines make up what I was calling the "bottom" picture. The three horizontal lines along with the bigger bright vertical line make up the "top" picture. Feeding the signal with the generator makes the bright vertical white line stationary and straight, thereby easier to see. You can see that there is also retrace lines through the picture but that is another fight for another day.
http://farm7.static.flickr.com/6206/6057597370_9bde945f33.jpg
The second picture is with the output of the generator decoupled from the antenna input but still near the input terminals. You can see the signal go down and a bit of static starts to appear. The bright white vertical line starts to curve and make an S pattern. The line has this shape and sways when the set has a moving video signal.
http://farm7.static.flickr.com/6206/6057050151_82d00f4bd8.jpg
The last image is with the lead from the generator decoupled and out of close proximity to the set.

OK, the large disparity between bottom and top should be fixable with the vert. linearity control. Since the lin. and height adjustments are interactive, you'll probably need to juggle both of them several times to get the sweep linear with a bit of overscan at the top and bottom. The vert. hold will probably need resetting as you adjust lin. and height.
The screwiness of the display itself doesn't appear to be from overloading, since reducing signal strength doesn't cure it. It almost looks like the video is negative (phase-inverted). The diode M4 couldn't have gotten connected backwards, could it? The banded (cathode) end should connect to the last IF transformer (L9), and the unbanded end to the junction of coils L10 and L11. The photo you posted earlier shows it connected correctly, so i dunno how it coulda gotten reversed. :sadwave:

Maybe you could post another vid with the VCR, with the signal loose-coupled and the vertical adjustments having been made.

Heat can fix them to I have a Zenith that had no video and almost no sound. Unsoldering and resoldering the detector diode fixed it.

Things can also sometimes get fixed by installing the diode correctly :stupid:. I did a bit of adjustment of the vertical tonight. After only 10 minutes or so of adjustment along with the the diode being correctly installed :sigh: has given much better results. I'll put some more time in tomorrow on the vertical adjustment to see if I can tweak it in better.
http://www.youtube.com/watch?v=KsvPeGGhkpE

You mean the diode wuz backwards?:saywhat::eek:

I think that the vertical frequency is still not right. I believe that it is running at 1/3 the correct frequency. If all the component values in the vertical section check out then in your shoes I'd start tweaking resistor or capacitor values in the vertical osc.

Though I may be wrong or confused by camera related issues.

You mean the diode wuz backwards?:saywhat::eek:

:worried:Sorry.:worried:
That makes two blunders on my part caught by Bill's eagle eye.:ntwrthy:

I think that the vertical frequency is still not right. I believe that it is running at 1/3 the correct frequency. If all the component values in the vertical section check out then in your shoes I'd start tweaking resistor or capacitor values in the vertical osc.

Yeah, 'specially since the little blocking transformer (T2) has been changed, the osc. might be running too slow for the vert. hold to pull it in. If so, the 1.5 meg resistor (R65) coming off the top of the hold control would be the first thing to tweak.

That makes two blunders on my part...
Hell, don't think of them as blunders. Think of 'em as learning points.:cool::D

Bill's suggestion about checking (or changing) R65 sounds good.

If it's any consolation, sweep problems are very common in old TVs. I'm nearly finished recapping my RCA 721TCS, which has both vertical and horizontal issues in its current state:

http://antiqueradio.org/art/temp/RCA721TCSSweepProblems.jpg

It still contains bogus caps and many unchecked resistors, so I'm hoping these zits will clear up in the normal course of things.

You are definitely getting closer with the Majestic. In some ways, this is the most exciting part of a restoration. You can see that success is within reach!

Perhaps it's my short attention span, but once a TV is working normally, I tend to lose interest and get an itch to start the next project. Yes, I can sit around and watch it, but there's nothing fun to do with it, if that makes any sense.

Phil Nelson

Rather than just ask whether to go higher or lower in value on R65, can some one tell me what R65's purpose is without telling me higher or lower?

Rather than just ask whether to go higher or lower in value on R65, can some one tell me what R65's purpose is without telling me higher or lower?
Well, note that it's in series with the 1 meg. vert.hold control. And also the .0047 cap (C48) forms a time constant in combination with R65 and the v.hold control. Ie., lower resistance = cap charges quicker. Higher resistance = cap charges slower. So if the oscillator is running too slow for the vert.hold to correct it, which way would you want to go with R65's value?

Lower. Thanks for not giving it away too much.
:banana: http://www.youtube.com/watch?v=yU6BfOV4_fc :banana:
Pay no attention to the massive explosion at :14, they are filming Batman directly outside of my window.
Still much work to be done!

Yay!! What a difference one little part can make.

Phil Nelson

Well done, Mr. Dragonslayer! I gotta congradulate you on your tenacity and perseverance. That set started out with multiple and disparate problems, and contains some novel/'oddball' pre-standardization circuit fratures. It would have been a signifigant challenge even for a seasoned techie. She's definitely on the home stretch now.

Was that the Batmobile backfiring outside? :eek:

It was a tumbler getting blown up.

Hmm.. seems to be a vid of it here (after the #!@$%^&* commercial) -
http://www.wpxi.com/video/28907146/index.html
But still trying to figger out what a tumbler is.:headscrat

Home Stretch it is!
After much adjustment of front and rear controls I've got is as linear as I could. A couple notes: the sound is terrible, I have to turn the set up much too loud to hear anything. The video below shows what happens to the picture when I adjust the contrast control. The video starts with the contrast cranked all the way up then some adjusting from all the way up to all the way down a few times.
http://www.youtube.com/watch?v=jVzPM6IlFeE
One other thing I've noticed is that the picture isn't level, it slopes from left to right. Is there an adjustment for that, or is it a symptom of another problem?

Home Stretch it is!
After much adjustment of front and rear controls I've got is as linear as I could. A couple notes: the sound is terrible, I have to turn the set up much too loud to hear anything. The video below shows what happens to the picture when I adjust the contrast control. The video starts with the contrast cranked all the way up then some adjusting from all the way up to all the way down a few times.
http://www.youtube.com/watch?v=jVzPM6IlFeE
One other thing I've noticed is that the picture isn't level, it slopes from left to right. Is there an adjustment for that, or is it a symptom of another problem?
WooHoo! Is that cool or what.:cool:
The bending when you turn up the contrast is related to the rather primitive sync take off scheme; it picks the sync off after the contrast control, after the video output stage in fact.:eek: Bending and "flagging" with an overly strong signal or high contrast is generally just part of the charm of such early designs. Does it straighten up if you reduce the signal strength at the antenna input?
To level the picture you rotate the yoke. There has to be something to loosen so the yoke can turn, then you tighten it again.
On the low sound, have you replaced C4, the little 4 mfd electrolytic that connects to pin 2 of V9 (the 6T8 tube)?

WooHoo! Is that cool or what.:cool:
The bending when you turn up the contrast is related to the rather primitive sync take off scheme; it picks the sync off after the contrast control, after the video output stage in fact.:eek: Bending and "flagging" with an overly strong signal or high contrast is generally just part of the charm of such early designs. Does it straighten up if you reduce the signal strength at the antenna input? (the 6T8 tube)?

Thank you. That was all I needed to know because my set was flagging when the contrast was turned down. Something was backwards! M5 was backwards, eureka! I installed M5 correctly and made some adjustments and got what you see in the video below.
http://www.youtube.com/watch?v=CgN4siWzFGo
We are so very very close to:beerchug:.
Just some audio tweaking and getting rid of retrace lines to go.

Congrats! Almost there!

(BTW, I was listening to Let me hear you scream by Ozzy while I was watching that video... made for an interesting combo, and fit creepily well at times.)

Thank you. That was all I needed to know because my set was flagging when the contrast was turned down. Something was backwards! M5 was backwards, eureka! I installed M5 correctly and made some adjustments and got what you see in the video below.
http://www.youtube.com/watch?v=CgN4siWzFGo
We are so very very close to:beerchug:.
Just some audio tweaking and getting rid of retrace lines to go.
Lookin' goooood. :yes: Yeah, you always gotta watch the polarity of diodes. The banded end denotes the cathode. That's universal practice AFAIK.
The retrace lines may go away at lower brightness setting. There doesn't appear to be any retrace blanking. Another 'charm' of some early sets.

If there's no retrace blanking then it's damn near done. Just a bit of audio performance to go.

If there's no retrace blanking then it's damn near done. Just a bit of audio performance to go.
Just a passing thought-- if you go to tweak the audio adjustments, whatever you do, don't touch any of the video IFs. The video IF alignment looks really good. Fine detail in the pic looks good, with no ringing or smearing which would indicate alignment was off.

If you're going to chance tweaking the audio IF "by ear," without following the factory procedure, you can make a little flag of tape for your screwdriver handle. Note which way it points when you begin, and then count how many half turns (or whatever) you go in a given direction. That way, if your adjustment makes no difference, or it makes things worse, you have a way back to Kansas.

Phil Nelson

This is a true story: the Boss hired a new guy on as a tech who obviously had had some experience with radios. About the first or second day, he got a TV on the bench with weak video. After testing tubes the problem persisted and the guy started twiddling the video IFs to get them "on peak" for maximum gain.

Pffft...HAHAHA!
You gota be seriously green to make a mistake like that!
That is gota be the funniest thing I've read in a while here.
Tom C.

Even I knew not to "fiddle with it" until it looks good.

I'm going to call this one done. It has been quite a journey over the past four months. I can't believe how much I've learned and I can't believe how much I still don't know. This project would have been a dead starter had it not been for the help of all of you here. I'd like to thank everyone who helped me on the way, ggregg, wa2ise, miniman82, Electronic M, Banderson, roundscreen, ChrisW6ATV, earlyfilm. Thank you jeyurkon for giving me a start with the schematic. Thank you Phil Nelson for giving me things to read before I even started. Thank you VintagePC for being the friendly voice that encouraged me along the way. Most of All thank you Bill C. aka Old Coot. Your name is well known and loved in my home. This television was repaired by your patience, intellect, and willingness to walk me through every step of the way. I am eternally in your favor.
http://www.youtube.com/watch?v=IYnywMhG_Ok

http://farm7.static.flickr.com/6187/6081405422_6538930568_b.jpg

Aw shucks. :o T'warnt nothin' really. Y'know, when i retired from doing this stuff nearly 30 years ago, i never dreamed of ever getting into it again.. or of "doing it" vicariously through a yet-uninvented magical medium. Doing it 9 to 6 for a living was not fun, but doing it this way is immensely enjoyable.
By golly did you refinish the cabinet too? Looks terrific.
oc

Aw shucks. :o T'warnt nothin' really. Y'know, when i retired from doing this stuff nearly 30 years ago, i never dreamed of ever getting into it again.. or of "doing it" vicariously through a yet-uninvented magical medium. Doing it 9 to 6 for a living was not fun, but doing it this way is immensely enjoyable.
By golly did you refinish the cabinet too? Looks terrific.
oc

Cabinet is not refinished. It looks way better in that picture than it does in person.

Yee-hah! Nice job. You have been very persistent. Now, relax and watch some movies!

Phil Nelson

In later sets after the damper circuitry had become standardized (damper tube in series with the flyback's B+ path), there was a little trick that was guaranteed to bump the width out a tad, while dropping the HV a corresponding amount. That was to take a disc ceramic cap of 82 mmf (82pf) rated at 4KV or higher, and connect it directly across the damper, cathode to plate.
Your set has a different damper configuration so i can't guarantee it would work, but it might. It might be worth a try sometime later if you have the chassis out for something else. It wouldn't hurt anything. Dropping the HV a smidgin would give a little more headroom for the arcy sparky 1X2.

Time to pop the champagne!

Your first restoration was better than mine.

I basically got enough info to start me fixing radios from a friend and eventually forced my self to figure out TVs. There was much I did not know too and I need to revisit my first project because unlike you I was not aware of the forums then, and made two big mistakes which were leaving one or two papers in and replacing many papers with ceramics which causes my set to jump out of synch periodically.

You done good.

Tom C.

And thank you vts1134 for your perseverance. It is a shining example to those of us with TVs that need restored and have yet to dig in. Thank you for posting your triumphs and your mistakes both.

This is just a downright awesome thread of everybody working together. Good job to all involved. I hope I can get similar help when I start my Zeniths :)

Looking good! It's great that you didn't give up.

Your first restoration went much faster than mine.

John

Well, the Mighty Monarch is safely in its new home in Buffalo :) . Managed to catch some I Love Lucy on her....

http://i44.photobucket.com/albums/f9/hondacuraworld/IMG_5339.jpg

Wasn't sure, John (vts), but it seems like the picture gap on the left is a bit greater than your other photos. If that's the way it is, so be it.....I'm still thrilled with her! Didn't know if something got shifted around on the trip.

Here's a pic when I first got her home, on an obviously off-tuned station

http://i44.photobucket.com/albums/f9/hondacuraworld/IMG_5334.jpg

I was amazed by the level of restoration of this set, including what I believe is a brushed on coating on the CRT. Simply incredible. This one will be with me forever :)

Got it in the house when I got home Saturday, and Sunday I set her up on a furniture mover so I could wipe down the cabinet with some linseed oil, which made it look even better than it did. I think I may send the cabinet out for a complete refresh in the spring.......

I read every post in this thread today. I had absolutely no idea that so much thought and work went into this set. I'm simply speechless. The amount of knowledge here leaves me in the dut 99 times out of 100, but this really showcases the amazing talent pool we have here on VK.....

You guys are simply amazing :) , and I have a new level of appreciation and respect for this piece, as if I didn't have enough before....

This set was quite an adventure and an amazing learning process. I was simply the hands and the knowledge came from others here. I really learned to be meticulous with restorations as most of the problems I had with this set was caused by my making mistakes.
The width does appear to be reduced from the last time I fired the set on. It usually got to be almost full width after the set warmed up.
Enjoy the set and definitely post some pictures of the cabinet if you get some work done on it.

Happy 5th anniversary Majestic! Five years and one day ago I set off on a life long journey that started with you. You introduced me to a passion for early television and a community of people who consistently surprise me with their willingness to help others. You may not have known it when you first caught my eye on the second floor of that antique store, but you would go on to introduce me to friends I may have for a lifetime. Even five years on you manage to put a smile on my face just remembering our time together.