Recapped powersupply section separate chassis and thought Id see if it had life by variac. Absolutely nothing. My shaver cheater cord is making contact and power switch working. Thought Id check fuses and discovered holder for both fuses was/is/ in the process of failing. Hunting for screws/nuts to fix this then see if tubes light.
Fixed fuse block with screws and nuts. Now power supply tubes light up but tv chassis filaments seem to be not lighting. dont know yet if this is a series string tube chassis. power supply does have a 6k6 instead of a 6v6 tube in it. Not sure thats good for testing or not.

It is not series string. You need to make sure that connector from power supply to TV chassis is making good contact on all the pins. Put some pressure on it and wiggle a little while it's powered up and see if the TV tubes light up

I created a YouTube series on restoring this set you might find useful.
https://youtube.com/playlist?list=PL4aHiwoXvLGA6lr13xGxkxFV3Y20pv6Nb&si=I5eouW5jJSvC1YQM

ok y es had thought you made a video of this chassis. also found it on schematic. so yes not series string. coudnt find your video series on it so yes thanks for that.
Update: wiggled and reapplied radioshack tuner cleaner and lube with my finger to the main power supply connector pins and reinserted several times and got all tubes to light. Bonus is picture tube raster so its recapp time of the rest of it. Ratheon picture tube. ON back on back of hv cage in pencil crtube 2-9-52 so thats very cool. Maybe thats why inside of tube doesnt look very burnt at all near element like high mileage crt's do. Tested awesome on the cr70 sencore tester assuming the tester is accurate. going to have to watch the banderson 20b1 chassis series I found one of them but they didnt autoplay as Id hoped. Raster picture is at 90 volts

Fantastic!
By the way, after you upload an image you can wrap the resulting URL in ' your image URL ' and it will display in the comment.

http://www.videokarma.org/attachment.php?attachmentid=206679&d=1719061318

http://www.videokarma.org/attachment.php?attachmentid=206680&d=1719077139

Ok I had forgotten that img thing posting pictures, since its been a super long time since I had even messed with radios/tvs.

https://www.youtube.com/shorts/xU_c2sI6upU
Also trying to figure out how to get raster more twards the bottom of tube currently. Picture looks like its maybe rolled over?
After 3 caps installed to replace multisection cap,(1st 3 caps in main chassis I had done!), I lost raster, had to figure out why! Translation: I had decided after the complete tube test and pin straighten(daughter helping so maybe too much extra tube wiggle widened socket pins) with dabs of deoxit on tube pins, I took the chassis over to friends house, did the 3 caps and bam no raster! discovered yet again tube filament problems. 6bg6 wasnt lighting. I even tested the 2 and 7 pins to discover no voltage. I dont know if I tested wrong pins or wasnt supposed to test for ac but no voltage. Decided to tighten tube socket pins because it just didnt feel right and bam tube lit after that. Tube gets same voltage as other tubes so its not like that tube had its own special voltage.

I really do need a readable schematic. I think I got mine off the etf but I cant seem to download new eyeballs to read it.
Wow! In beginners guide to tv restoration part 4, I noticed your ion trap, the screws are totally horizontal. Mine are not! Different picture tube maybe, Makes me wonder if My ion trap is way out of adjustment. For the pie dual 40 micro farad caps I used 47uf at 450 volts.

For your re cap do it one stage at a time. Recheck as you go every few caps.
Order is: power supply - HV & horz - vert - then the rest......
Many sets never work again after a re cap so go slow.

47 mfd is fine for 40's. Off the shelf caps come in 1, 2.2, 3.3, 4.7
10, 22, 33, 47 etc. SO use a little higher in mfd, voltage & heat.
Tolerance is high ( 20%) anyhows.

good luck
Zeno:smoke:
LFOD !

Ion trap magnet position is going to depend on the CRT electron gun structure and how the CRT is positioned on the chassis. It won't be the same from set to set.

I didnt recap by stage but I think I did by area of chassis. 3 to 4 caps at a time and test fire it. I dont have enough experience to recognize a stage just by looking at it from underneath just because Ive never tried to identify a stage but maybe I should try to figure out exact stage beginnings and endings with this tv. Raster is close to bottom of screen now. still not at bottom though maybe less than 2 inches. Trying to remember what adjusts total vertical position up and down or maybe there isnt an adjustment for that and something else is off. I didnt try to crank up voltage above 90 volts I forgot. picture faded dark when I went over 90

Hi,
I am entering your discussion late.
ACCORDING TO YOUR VIDEO YOU HAVE TO CHECK RESISTORS!:yes:
The fault in question could be a problem with caps, tubes and resistors!
Just when you pull the old caps, it is a chance to test resistors, with one end
in the air!
There are not so many in the vertical section.
From my experience I like to say, your issue is a combination of caps and resistor(s)!
They are aging fine...:thumbsdn:

Regards,
TV-collector:stupid:

Right now Im having problems with the 6bg6 tube. I thought the pins were loose because its not lighting again. Either the socket is really that bad or voltage isnt getting to the tube or the tube is some how being affected by something dont know yet

Is yours a TV only or combo unit? The combo unit cuts filament power to the 6BG6 when in radio or phono mode.

television only as far as I know. if theres a radio hook up to it I dont know. chassis says 20b1.. maybe me cleaning and tightening the tube socket is just coincidence that the tube lights sometimes. I did get to test the voltage at bottom of socket once and it was like 4.98 volts......thats low!
Just looked on front and I do not see any indication or printing of the word radio or phono on front of cabinet
https://www.youtube.com/shorts/15qjJ2yhfvk

Yep, TV only for sure. All the tube filaments are wired in parallel. What's your line voltage going into the set? Should be at least 117 VAC. These sets draw quite a bit of power. Could be your line is sagging.

Other tube filaments do not dim. Only the tubes 6bg6 and 1b3 get dim when screen goes away if i turn up voltage past 90. Screen faded once when i had it at 90 too.will check line voltage at tv chassis but dont think voltage is dropping

Must fix weird 6bg6 filament works/then doesnt work issue...I wonder if its arcing making filament do that

You are running the set on only 90 volts? Use 117.

Ok then run on 117 and test....i guesss alll caps are replaced except for the single wire can that just says a part number on it...no value on it..havnt looked it up on parts list yet.
I do still hear vertacle buzz when picture is faded out and or 6bg6 isnt lit. Can also vary the buzz with front control knob. Makes me also wonder if a resistor is getting hot and opening. Restors are next anyway.
Fascinating! I just figured the high voltage was going away when I cranked it to 117 volts. Its not. Screen lit about 100 volts measured and high voltage is about 7k. When I crank it to 117 volts the high voltage goes to 9k which is what schematic says. Weird its like somebody cranks down the brightness to zero with in 5 seconds after I crank up line voltage to 117.
I did manage to check the 6v6 audio output tube to see if somebody biased it differently because it had a 6k6 installed. Seems wired for 6v6 so I popped in a 6v6.

I decided to mess with ion trap magnet. and adjusted it for full brightness. Low and behold 117 volts and I got a screen! So, because I only know that the magnet redirects the electrons back to the screen, very fascinating that with the ion magnet off... screen is affected by line voltage level almost like line voltage affects when screen electrons hit screen.

Line voltage will affect the current flowing through the focus coil which interacts with the ion trap magnet. It's all connected.

Still trying to wrap my head around ion trap being off and raster showing up then fading out the second i turn up line voltage to 117 volts. Would have thought raster would still be visable just not as bright. So the second i turn up line voltage i guess the warm up of tubes changed something the same amount of picture raster fade time

As bandersen mentioned, they are interactive, the fields for the focus magnet AND the ion trap, the tube was designed to work with a combination of both to deflect ions away and electrons to the front, as bias is slowly raised, this will cause a respective ramp up in the electromagnetic field of the focus coil, and w/o the ion trap in place, you can expect weird stuff to happen as it rises to full power.

Absolutely. The magnetic fields interact. Always run the set at full line voltage, adjust the ion trap magnet and carry on :)

yeah the only reason for power up was recapping and checking like old radios. The ion trap was in place and close eyeballing where it had been when I took it off but not exact. When I saw it dim out as voltage passed 100 volts, I thought something was shorting out or burning up.

I do not have a 4 mfd capacitor that c207 is and its on pin 5 of the 6al5. Im going to guess a 10uf may work. I might have a 4.7 mfd somewhere but dont remember the voltage of it. max volts on parts list shows 50 volts. WELL I just found it. 4.7uf at 450 volts. Installing it now.

Well I have recapped the 4 mfd cap and replaced my dual caps 153k and 333k that made .05uf twisted together with actual .05uf mpt caps. Focus adjustment used to work, now it doesn't focus or seem to focus.
More possable problems is the 1b3 filament seems way too bright at 117 volts. I know this tube is powered off the flyback so whats up with that? Adjustment way out of whack causing it to draw more filament current or a bad 1b3?

is this tube too bright. I have read that a 1b3 is barely able to throw enough light to be detected unless room lights are off!!!!http://www.videokarma.org/attachment.php?attachmentid=206694&d=1719696058

is this tube too bright. I have read that a 1b3 is barely able to throw enough light to be detected unless room lights are off!!!!http://www.videokarma.org/attachment.php?attachmentid=206694&d=1719696058

http://videokarma.org/attachment.php?attachmentid=206694&d=1719696058

looks normal to me!:D

you want to see abnormal...
​​http://suzaku.live-evil.org/0317201339a.jpg

gassy 1b3??? I had a philco 80 tube do that untill it failed. I guess I will go back to figuring out what makes focus work. cant get horizontal to lock yet.

Check the power resistor in series with the focus rheostat.

r332 I think your reffering to and that says 3000 ohms on schematic. Checking now. The 25 watt power resistor 8500 ohms in the hv cage is open.
trying to come up with an 8500 ohm substitute in the mean time. 25 watts is definetly a huge one

Yep, they're always open.
You can use a 10K - 20W (or better) in parallel with a 56K - 5W resistor.

the sand resistor measures 1.867k ohms.

I found two 12k ohm 20 watt resistors which would make 6k or just use the one 12 k ohm itself.

The 8.5K resistor in the cage has a big impact on the horizontal linearity. Try both and use the one that looks better, but I suspect you'll need to get closer to 8.5K to get good results.

Yep, they're always open.
You can use a 10K - 20W (or better) in parallel with a 56K - 5W resistor.

Was I lucky then that mine was OK? :scratch2:

I guess I will just put the 12000 in for now as I dont have anything smaller or a 56k that will work. Going to order a 10k adjustable 50 watt one.

Im wondering since focus is just voltage supplied from the power supply to the focus coil that a connection issue is up because focus rheostat is good as well as the sand resistor as well as the focus coil itself. I had the tv on its side and ok yeah I got some focus adjustment back, put the tv right side up no focus. Gotta be a connection issue and I suspect that power socket plug rear of tv for starters.
Messed with the horizontal linearity adjustment because it was screwed most of the way out like an inch and almost a half of threads sticking out. I can get picture to stop rolling and almost sync up but not sure what to adjust next unless controls on the back are still way out of adjustment. I tried flipping around the ionmagnet and that made centering a nice bright picture much worse only half the image showed up so I put it back the way it was.
I figured well maybe they messed with the magnet and screwed that up too.
Not sure how the 12k ohm resistor is affecting me getting an actual picture. but focus is still no go.
https://youtu.be/4_xPEqhBqdU

Have you adjusted the horizontal freq coil?

if the horizontal freq coil is on the back of the set then yes. Have seen horiz lin and horiz lock. I can get horizontal lock to sorta untear the picture midway adjustment but I would think it would keep untearing and show a picture but picture just gets worse outside either way of halfway point.

Was I lucky then that mine was OK? :scratch2:

The dreaded RCA with the horizontal devil still lurking in it has the big 5.3 K resistor that controls horizontal linearity in the HV cage. It is stepped with additional tabs that add 500 and 1 K ohm if you move the lead coming from the horizontal yoke. I was going to replace it with a variable power resistor but it was perfect, dead on 5.3 K. In fact, I had it out of the chassis to clean out the HV cage and was ready to replace it until I measured it. So, yes I guess having a working HV resistor in the horizontal deflection circuit is rare and we are fortunate. I may change it anyway now as I'm trying to eliminate everything as a possible source of the issue.

If horizontal frequency is different than horizontal lock, horizontal linerity then no i havnt adjusted that one yet....maybe under the set..will have a look. Third adjustment was vert linearity i thought

No, it is horizontal lock

Well, I installed an adjustable 10k ohm resistor and set it to 8.4k I dont know if it made a difference or not. I would think horizontal linearity would shrink sides of picture inwards or outwards and its still super wide off the screen. Also possable this leader lcg 400 test pattern generator now doesnt work but zero experience knowing what Im even looking at.
https://www.videokarma.org/attachment.php?attachmentid=206699&d=1720050469

Your horizontal frequency is wrong. Can't you adjust the hor. lock and hor. hold and eliminate the horizontal bars?
Adjusting lock one way should increase the number of strips and decrease the other way until they are gone.

messing with horizontal lock and front switch now. Maybe they are just way out of whack. Got focus back, not certain its right but its back after sand resistor replacement of 3k. http://www.videokarma.org/attachment.php?attachmentid=206700&d=1720063868

Ok jurys in on this one. Decided to hook up my leader lcg 400 to my 20 inch crt set cerca 2001.......NO PICTURE! FLipped buttons switches until picture appeared! Hooked it to this tv and we now have laid an egg. I had all the switches off on the generator, I guess luminance has to be on. Now I have to figure out how you shrunk your horizontal image to fit the screen. Maybe it takes a good amount of turns to affect the image for horizontal and vertical linearity. Also wondering since my ION magnet is practically up against the focus coil that the focus coil and the ion magnet are not in the proper adjustment. Especially the focus coil, it doesnt seem to be perpendicular to the neck of the tube.
http://www.videokarma.org/attachment.php?attachmentid=206705&stc=1&d=1720065341http://www.videokarma.org/attachment.php?attachmentid=206706&d=1720066548

My picture runs off left side of tube.so more fiddling

The focus coil also effects centering. If there isn't additional centering controls on the set the general idea of the he focus coil is adjust for best focus, try to get centering as good as you can and avoid corners getting neck shadow from the focus coil adjustment.

The first thing I would do is adjust the vertical pots to get the vertical linear. If you can achieve that and have sound, then slide the chassis into the cabinet and adjust the sweep (and possibly focus and trap) with the cabinet mask present. The mask will tell you if you have too little or too much deflection, and if you're centered.

Trying to get picture close to being centered. Focus coil, ion magnet. http://www.videokarma.org/attachment.php?attachmentid=206707&d=1720102608dth control, horiz linearity. NOt having much luck yet gettting piccture to move to the right.
Messing with this quite a bit getting it to center and shrink. Controls were messed with quite a bit. Width was all the way in and hor. lin. was most of the way out. Im wondering if messing with the power resistors ohms would help me get more adjustment.

Have you adjusted the horizontal drive control? It will affect width and horizontal linearity.

yes I tweaked the drive as well

and what affect did tweaking it make? It's a variable cap and most of the change happens when it is tight clock-wise. The width coil will only change the width maybe 10% from one extreme to the other.

If your set has a double-d mask, the image should extend slightly off screen on either side. You squares look pretty good so I'm thinking your width is just about right.
Looks more like the linearity is off a bit. More compressed on the left and stretched on the right. That is messing up your centering.

Yes, luminance needs to be on. Luminance image info is the brightness as compared to chromanance which is color info.

yeah I havnt figured out what will fix the centering. Maybe check all resistors in the horizontal verticle area. HAVE noticed the drive adjustment and its effect at almost tight ness.

No, that won't do anything. Please answer my questions. I'm trying to help and the more info you can provide the better.

The electron beam comes straight down the center. The only think moving it around is magnetic fields.

It looks like your horizontal linearity is off. Is that correct? Is the image more compressed n the left than the right? If so, you need to fix that before you worry about centering.

Linearity is affected by the damper tube, horizontal output tube, horizontal drive and the linearity coil.

The left side is controlled mostly by the damper circuit and the right by horizontal output circuit.

Once you get that sorted out, you center the image by adjusting the screws on the focus coil.

It was more compressed to the left, wife and daughter noticed it. Ive messed with it a lot. Also not sure which pattern is best for picking out the skewed linearity issues. Set before I took out the chassis. I dont know if it has sound yet I need to hook up the speaker.
http://www.videokarma.org/attachment.php?attachmentid=206710&d=1720132959

Yes, that's a double D so your width is close to correct. Now I'm seeing distortion in the upper left corner. Could be yoke is not all the way forward, or ion trap misadjusted or focus coil misadjusted. My money is on the ion trap magnet.

How does regular programming look on it? That was the criterion for most any service shop back in the day. That slight bit of horz nonlinearity in your last screen shot would likely never be noticed.
The rule for ion trap adjustment is max brightness consistent with no neck shadow.

The thing that interests me is how the upper left corner is pulled in. I think that has to be caused by the positioning of the neck components.

Yes most likely neck parts..I was tweaking those as well. It didnt have this issue before.
Whats also interesting is the more I messed witht all the controls especially the back ones is they cleaned up and the set became more stable when adjusting and also basic operation

Fantastic. Sometimes they need to run a while to work all the quirks out.

I would suggest the upper left may
be affected by a stray magnetic field in the bell area of the CRT. It could be caused by a piece of magnetised metal strapping in that region.

The raster is deflected inward horizontally and vertically at the same time which should exonerate the deflection components.

You might try using a degaussing coil to see if it can remove the magnitism. A permanent magnet placed in the region should counteract the stray magnetic field.

Cloth strapping. There shouldn't be any metal in that area.

I think you may be right. A stray magnetic field. Because I have the focus coil. Quite a bit off from perfectly parallel horizontally and vertical to the neck of the tube just to get the picture centered.

I have reception on the set now because I wanted to see if we had sound. Sound is very faint and distorted. When I bought the tv, it had a 6k6 installed in the 6v6 output tube spot for audio so possable source of crude faint audio even while fine tuning the audio knob.
As far as the neck goes I have the focus coil super tilted sideways horizontally to center picture.
Just plugged a kids game into the audio rca jack on the power supply.....sound gets through and loud using a radio shack 8 ohm speaker so yeah sound in main chassis time.
I have sound, I tweaked the 1st sound I.F. transformer. Sound got a lot louder, not as loud as it should be but better. I dont know if 8 ohms is the proper speaker. Havent tried the original speaker yet. I would like to get a degausing coil. Not sure I have any of the computer monitors anymore that I could rob one from.
Does anyone know the correct ohms for the speaker? Schematic shows nothing, neither does parts list other than "speaker" with part number.

You don't need a degaussing coil. It's distorted because you have the focus coil tilted so much. Fix the horizontal linearity issue and your centering issue will be resolved.

Ok so horizontal lin out of proper appearance is tubes, coil, or somerhing else out of adjustment. Ive seen cathode current of horizpntal output tube adjusted on youtube but not sure that applies here. I should post up a video of what the horizontal drive does when I adjust it. Those 2 coils over the power supply plug I have messed with.

Yes and left side is mostly controlled by the damper circuit. Easiest thing to try is swap out the horizontal output and damper tubes if you have spares.
Adjusting the drive should affect the linearity, width and brightness. The service info outlines how to make all the horizontal adjustments.

6bg6 I have swapped out just because thats the tube that kept on not having the filament light at times. 1b3 I have many of. Dont remember the other tube uness its the 6w4 theres one of those might be more would have to look at schematic agian

Yes, damper is 6W4 and there is only one in the set. There is also a cap on either side of the linearity coil. 0.047 and 0.035 if I remember correctly. You could try tweaking those values.

.035 is now .033 so I could add some value to that. I will have to look for a .047. I do remember .05......yes thats the same cap in the tiny admiral that was suggested to mess with because if I remember correctly the same linearity issues. I have swapped out the 6w4, 6sn7 6al5.
Sound I think works fine now since I have wired up the original speaker. Its ohm value is 3.5 ohms so thas why low sound.

I thought about going larger with the .05 cap gonna try that...something has to move picture to the right

I thought the linearity was okay? Changing the capacitors won't shift the image.
To center the picture these type sets, you have either centering rings on the yoke, potentiometer controls to vary a dc current though the yoke windings or move the focus coil around. I believe this set don't you just adjust the focus coil?

Yes, focus coil and he has it adjusted to such an extreme it is causing distortion in the upper left. It sure looks to me like the image is compress a bit on the left side and stretched on the right. If that was corrected, it would shift the center to the right.

I'd prefer to watch an image that was a bit off center but not distorted like you have it here. The corners of your programming are going to be cropped off anyway.

I'd also try a different signal source if possible. I think you are using a Leader LCG-400? It is entirely possibly that circle is not perfectly centered in the test pattern.

http://www.videokarma.org/attachment.php?attachmentid=206709&d=1720126248

How does regular programming look on it? That was the criterion for most any service shop back in the day. That slight bit of horz nonlinearity in your last screen shot would likely never be noticed.
The rule for ion trap adjustment is max brightness consistent with no neck shadow.
Im still learning how to even recognize what all the picture issues are. More experience I guess. Somebody on the forum points out something on my picture tube image and I hadnt even noticed it. After its pointed out I see it which is good thats why Im still hesitant to put it in the cabinet till all the major oddities are fixed. Leader lcg 400 on 2001 flat screen crt 20 inch tv
yes Im using the leader LCG 400.http://www.videokarma.org/attachment.php?attachmentid=206722&d=1720648259

Changed out .22 capacitor for two paralleled .1 caps to make .2 for original value. This cap goes to the 6bg6 tube. I tried adding caps to the .035 cap which is on the left side of horizontal lin. coil. Made picture shrink horizontally. I didnt want that. So caps on both sides of horiz. lin. coil are .035 and .1 I might mess with the .1. Also there was a 100 ohm resistor that measured 228 ohms. picture is better but i need to tweak it more to the right the whole picture. Focus coil isnt cranked hard horizontally lookin like its all crooked now. I still have it cranked but not near as much.

the picture still has flagging at the top if I use the front controls to center picture. Gotta be something else to tweak. unless that .1 needs checked/ adjusted value. The .035 seemed to shrink picture inwards both sides so maybe try smaller than .1 or slightly bigger we will see. it was fun zapping myself with the test wires of the .035 cap, I wonder how many volts that was. Actually it was the jumper cap I was using. Made daughter jump as she was sitting next to tv on couch playing cards when it made the zap sound.

Also need to find a power cord for it as i do not have one. Searching for admiral tv power cord on evilbay didnt get much

These use generic interlock cords that all TVs used back then. I think this used the ears style cord, but it may have used the groove style....Both are very hard to find.

If you need a cord that will plug into the socket on the back and power it, but don't need the ears or slot to interface with the back go to ACE hardware and look at the mixer cords in the extension cord aisle. Mixers and vacuum cleaners used the same cord for decades and ACE still sells compatible cords for the socket.

oh thats perfect although I dont remember seeing cords at ace but theres an ace 3 miles from me. Will go look. Plenty of time I have used a xbox cord that doesnt really fit and had been working on the set only to have it"fail" when all it was was the ill fitting cord losing connection. Talk about going bat guano crazy only to find the cord came off again!!

Im assuming the back of these tvs had the paneling style back and if they did mines missing.
Ace only sells the polarized version and mine has two round same size terminals. I guess Evilbay time.

Likely perforated metal like this, but might also have been Masonite.

https://live.staticflickr.com/2424/4081221669_8f071ecf8e_c.jpg (https://flic.kr/p/7dDk1R)

Power cord looks like this when installed.
https://live.staticflickr.com/7340/9738291332_6091dfbc7d_c.jpg (https://flic.kr/p/fQxhJG)

Im assuming the back of these tvs had the paneling style back and if they did mines missing.
Ace only sells the polarized version and mine has two round same size terminals. I guess Evilbay time.

Interesting. I've never seen one with the TV end polarized at ACE. Always the same size. Later 60s and 70s sets tended to be polarized so I'll have to see if my ace carries polarized now too.

Unless the wife didnt see another cord option at ace maybe there is but the photo she sent me looked like large hole and smaller hole. As far as the back of the set my cord option is the slide off hv cage, somebody apparently drilled it out. Dunno why.
UPDATE:ace does have non polarized cords wife didnt look close enough. Cord fits pretty good too!

You can in a pinch,use a small jeweler slot screwdriver to " squish" down the larger hole of a polarised cord to a smaller diameter.I would force the small screwdriver outside the metal connector of the larger hole and twist/bend the screwdriver around the entire circumference to force the larger connecter in.that will make it smaller. I did this many times in the past..hope this helps. RonL

I might try to mod a cord to fit.
Im now trying to remember how to display the test image on my d/a converter box with a usb. all my images are in jpg format. I dont remember why its not showing up on the converter box as a choice. Homeworx media sonic hw 150pvr. I have 6 test images on a thumb drive that I think might be all the same but they dont show up in the homeworx list when I choose photo. I also need to find more test images to download.
Update: heres the usb test picture.
I should take off the ion magnet and check to see if the focus coil is centered. I know its not perpendicular horizontally or vertically. http://www.videokarma.org/attachment.php?attachmentid=206731&d=1720994056

fascinating the picture I just took and uploaded was different than it looks now. Turn on tv take picture upload picture. Uploaded picture is with no warm up time. Picture gets shrunk some as it warms up and might even be clearer after warm up. I have put focus coil as close to yoke as possable and square to the tube. Latest picture of trying to dial it in. Makes me wonder if focus coil needs to be closer to yoke. I dont know what made image clearer, straightening of the focus coil or make it closer to yoke. Now picture seems to be oblong on right side but if I measure top to bottom and left to right its 6.5 inches for circle. Also is more pickey for horizontal lock so somethings out of adjustment because if the cables loose and I bump it introducing static it wont lock back on and picture tears unless I readjust it so must make sense, looks wonky and doesnt horizontally lock good. Oh the joys of tweaking not knowing what your doing. I try to adjust it so everything looks good and I get this line so I back it off and my pictures messed up some way or another. No idea why this line appears then dissappears depending on what Im tweaking.

http://www.videokarma.org/attachment.php?attachmentid=206732&d=1721075834
http://www.videokarma.org/attachment.php?attachmentid=206733&d=1721078439

messed with it even more. Its the drive control that makes these lines if I back it off from tight too much. Makes one line and if I back off more makes 2 lines. Is the picture double folding over telling me dont do that or is this not normal. Is this possably a vertical problem? Real wild guess is theres caps hiding that need replaced, or, the flyback isnt so flybacking.
I just tightened the horizontal drive adjustment. Its now at full stop tight. Not gorilla tight but vertical lines are even less now. Things to try are swap 6bg6 with original one and maybe see what other components can affect this creation of lines.
http://www.videokarma.org/attachment.php?attachmentid=206734&stc=1&d=1721079534

The horizontal sweep is not folding, but is stopping for a short time when the drive is misadjusted. What happens is that the flyback pulse occurs at the right of the picture, then the sweep current sawtooth for the left side of the picture comes from current reversing through the damper. If the reverse current ends before the horizontal output turns on again to make the right side sweep, the beam just stops in place until the horizontal output turns on. The correct horizontal drive waveform will turn on the horiontal output a short time before the damper stops conducting, so the sweep doesn't stop and there is no bright line.

If a flyback/yoke circuit could be lossless, the point where the line might appear would be centered left and right, but energy is lost in the resistance of the coils and by generating the high voltage, the energy left after retrace is less than was put in by the horizontal output, the left side sweep current through the damper does not last to the middle of the scan, and the horizontal drive has to turn on early and supply more than half the sweep, from somewhere left of center to the right edge.

Beat me to it

I guess IM just not seeing the point of horizontal drive if the adjustment needs to be basically tight to get rid of the lines, unless theres somewhere else to look. Drive is tight now and its a super soft line spread out about an inch almost not noticable. pictures still more left than it should be but I dont think thats fixable, other than focus coil messing with. I just need to hook up my scope which I suck at setting up, maybe that will get me on the downward slope of things. pictures definetly watchable but I really wanna understand this till my brain starts figuring this out on my own with out blowing up this tv.

Ok, I downloaded the schematic now.
I see the H drive is a variable capacitor. It would be interesting to know if the best setting is max or min.
Also: what components in the Hor. Osc and Hor. output stages have you measured or replaced?
Unfortunately the schematic I found has no voltages or waveforms - they would be helpful.

Have you adjusted the horizontal lock to get things synced with the horizontal hold centered?

I see that different valus of C419 are specified for different chassis. This seems to indicate that C419 and the attached capacitor C420 are critical.

Can you make parallel lists of resistors, capacitors, and tubes you have and have not tested or substituted in the hor. osc. and hor. out?

I havnt messed with c419 or c420 which should be 330 and 270 pico farads. Quite possable that a few micas are bad. I have replaced the 6w4 with another one I had. 6bg6 replaced evilbay new. 68 ohm resistor on 6bg6 replaced. 100 ohm off 6bg6 replaced. All the paper caps replaced I could find. 1b3 replaced because the old one I saw orange on the metal disc below the hat inside of it that some said thats normal. 6v6 output tube on power supply replaced because it had a 6k6. also I do believe the 6ac7 and 6sn7. Also the sand resistor in series with the focus rheostat replaced. Focus adjustment sweet spot is sorta close to midway on rheostat so thats good.

Dont remember if i adjusted horiz lock with the hold centered so i willl try that

Dont remember if i adjusted horiz lock with the hold centered so i willl try that

OK.
Then I would check all resistor values specifically in the Hor. oscillator and Hor. Output circuits. If no discrepancies, then I would try subbing those small caps or changing their value slightly to see if one fixes the drive line problem.

Drive cap needs to be fairly tight. Most of the change is going to happen when it is very tight t0 snug. That's only about a quarter to half a turn. The tighter it is, the less drive signal you have. Too much drive and the horizontal output stage is pushed too hard and you'll get distortions.

Have you checked/replaced the 68, 82, 100 and 1M resistors on the 6BG6?

Delete.

68 ohm replaced. 82 checked was93.4 and replaced. 100 was way out at 228 so replaced. 1meg was 448k replaced(under 1b3). 82 i might check again to be sure and other resistor under 1b3 was ok but should check alll again as test leads on one merer turned out to be intermittent

Delete.

https://www.youtube.com/watch?v=CniafOgpiW8

Well 82 ohm is now 84 instead of 93.4. Didnt seem to make a difference

Bought new 6w4..which it is 6w4gt so i willl put that in sunday but other than that i dont know. Swapped in 6w4 i just had from other tvso if thats causing issues then the new 6w4gt should make a difference. Still think crt also might have something to do with it along with possable crt centering is more than one issue.
Ok I wasnt aware that the swapped in 6w4 the first time was actually a 6w4gt and I think it was also new. I know the schematic says too much focus coil adjustment then something else is wrong but whats acceptable tweaking of the focus coil to get left right center and still have focus equal all over the screen? I do know that when everything was super way out I had the center of the screen focused and away from center it was out of focus and I couldnt get both adjusting focus, but now that I made focus coil square to the neck of tube and no left or right or up and down tweaking, I could then get the whole screen focused. I need more knowledge tools to be able to figure this out.

Checked resistors again. Found 1.8K cathode bias off 6k6 was about 2.4k and also a couple of the 47k were about 55k or above. Also the two 100k off of the 6al5 were 111k and 105k at 5 percent tolerance thats out so I replaced them. An alternate solution would be to shift the whole chassis in the wooden cabinet to the right and hog out all the knob holes, crude but effective. Strange things enter the mind when running out of options.
http://www.videokarma.org/attachment.php?attachmentid=206752&d=1721586523
http://www.videokarma.org/attachment.php?attachmentid=206753&d=1721586803

Resistors being out by 5 or 10% is not the source of your problem. They could be out by 25% or more and not cause this problem.

It is the horizontal deflection circuit and the magnetic fields.

Make sure you have adjusted the spring loaded mounting screws for the focus coil correctly. That is how you center the image.
Make sure the yoke is seated up tightly against the CRT.
Make sure the CRT is centered in the mounting.
Make sure the ion trap magnet is in the correct spot - it will interact with the focus coil.

When you move the trap magnet around, the whole image should shift and possible distort in the corners. Same goes for the focus coil.

Well I dont see any correct method listed in the schematic instrucions other than if it needs extreme adjustment then something else is wrong. The crt is up against the rubber support that butts up to the main crt neck holding bracket. If I adjust the focus coil to center the image I guess it doesnt matter how crooked it looks. I have no idea if the crt is centered in the bracket that holds it as I cannot see anyting unless I take it all apart. Is the focus coil supposed to be butted up against the yoke? Does it matter where on the neck of the crt the focus coil is located? I do know that the ion magnet seems to move the picture around but if I make it max brightness then right side seems shadowed.

Have you tried adjusting the screws in all four corners? Tighten and loosen to center the picture. The whole focus assembly can also be moved forward and back. Remember we aren't there. The more pictures the better. Take some from a few feet away so we can see the whole assembly from the top and sides.

I've repaired a few dozen of these Admirals and the only times I've seen anything like this was from mechanical issues with the CRT/yoke/focus coil mounting.

focus coil to the max to try and get raster across screen. Raster is almost to the right side of screen. What does moving focus coil forward and back do?
http://www.videokarma.org/attachment.php?attachmentid=206756&d=1721597810
http://www.videokarma.org/attachment.php?attachmentid=206757&d=1721597855

focus coil and crt setup side view. Sure enough focus knob is all the way to one side to get focus with focus coil cranked totally crooked just to center picture. So if the only thing left possably is mica caps.
http://www.videokarma.org/attachment.php?attachmentid=206760&d=1721599132
http://www.videokarma.org/attachment.php?attachmentid=206761&stc=1&d=1721599151

Moving the focus coil changes the strength of the magnetic field required to get a good focus. Since your focus control is at one extreme that tells me something is not right.

Here are the best images I have showing the neck area from some 20B1s I worked on for what it's worth.

https://live.staticflickr.com/65535/53872635393_1fb3a15936_c.jpg (https://flic.kr/p/2q5xkBg)

https://live.staticflickr.com/65535/53872635818_bce8345ef4_c.jpg (https://flic.kr/p/2q5xkJA)

https://live.staticflickr.com/65535/53872662913_b2cfd47a73_c.jpg (https://flic.kr/p/2q5xtMK)

https://live.staticflickr.com/65535/53872418001_0bef7b7059_c.jpg (https://flic.kr/p/2q5wdZ8)

Yes somethings not right and if I straighten out the focus coil, the focus knob setting also straightens out with sweet spot almost centered. I dont see how the crt couldnt be centered since its shoved into the rubber bracket coned gasket. Almost suspecting the crt itself. Notice how all your ion traps are close to up and down. I wonder if turning the crt clockwise would do something. No schematic diagram of crt mounting but is the yoke clamped to the neck whete i cannot see it? I Loosened the crt front strap to see if it would slide further rearwards. Seems like somethings holding it from sliding forwards even after ion trap magnet is loosened.

The yoke is not clamped to the neck. There is a thumbscrew on top holding it in place.
The CRT is only held in place by that strap. There are rubber pads underneath that often fuse and harden to the glass. That's probably what is holding yours down.

A thin knife can be used to break the bond.

The CRT anode is facing up on mine and the ion trap magnet screws on top.

The yoke is not clamped to the neck. There is a thumbscrew on top holding it in place.
The CRT is only held in place by that strap. There are rubber pads underneath that often fuse and harden to the glass. That's probably what is holding yours down.

A thin knife can be used to break the bond.

The CRT anode is facing up on mine and the ion trap magnet screws on top.

There used to be some kind of solvent (spray) to help get the yoke off, but I have never seen it other than in old books from the 50s-60s. :O

I doubt it exists any more.

Front of crt is loose when i removed the strap because the crt would come out a bit. I thought maybe the ion trap was holding it but no. I Was suprised something else was holding it in the bracket.

A hair dryer or heat gun on low should help loosen the yoke if it's stuck on.

Well I almost got picture tube out but tube socket wouldnt clear yoke, but Im not even sure I need to totally remove piccture tube unless possably somethings holding yoke from being straight against tube cone. I had forgotten about the little front tab on chassis holding tube in. I also wasnt aware that the top wing nut allows the yoke to be moved not only clockwise or anticlockwise but front and back. so i did slide yoke closer to front of tube. currently watching adam 12.
Im going to try to take the tube all the way out tonight. Might take 2 people to do it, one to hold the tube and other to get neck plug to clear yoke.

Some of the yokes had resistors and capacitors in them i wonder if this one does will find out when i get the tube out

t will definitely have two resistors - one across each vertical yoke winding. The are there to dampen any oscillations. There should also be a small mica cap across one of the horizontal yoke windings for the same purpose. I do not recommend messing with any of them.

decided not to mess with it. especially on recommendation of not to mess with yoke caps/resistors. Must be some kind of resonant circuit. Anyway tv seems to be vertically jumpy like somebodys messing with height knob, twitches to slightly smaller height picctures....after a while goes away. Will get short video next time I fire it up.

No, it's not a resonant circuit. It's just not worth risking damaging the yoke. If the resistors or cap are slightly out of spec, it's really not going to make any noticeable difference. If they had failed and you had ringing, it would be very noticeable on the screen.

very interesting. almost makes me want to get that sencore ring tester you have. Not sure how useful the sencore ring tester is.

A Ring tester detects is a yoke or flyback is open or has shorts. If you had either, it would be very apparent on the screen.

If you have horizontal ringing, you will see vertical bands on the left.
https://live.staticflickr.com/65535/53880752769_181f3c04e1_z.jpg (https://flic.kr/p/2q6fWC2)

https://live.staticflickr.com/65535/53880753764_6e1ebeb470_z.jpg (https://flic.kr/p/2q6fWVb)

And if those bands can be adjusted out then no bad yoke or flyback?

The pictures from Banderson show a non-failed, working yoke and flyback. This kind of ringing is a more subtle problem, not an out-and-out failure, and not an indication that it's about to fail either. A set can run forever with this kind of subtle flaw.

I don't have the experience to tell you what remedies to try for this, but it's not fatal.

I see there mention of the little high voltage ceramic or mica capacitor across the left side of the horizontal deflection windings of the yoke. I believe it is to balance the distributed capacity but also I think it helps "tune" the left hand side yoke to prevent these ripples.

Typically it is valued between 47pF to roughly 120pF. I recall they were often selected on test and weren't even assigned an exact value.

You might try experimenting slightly raising and lowering this capacitor value within the range above to see if there is any improvement.

Come to think of it, is the capacitor present?

Also while you are at it, you might confirm the 560 ohm vertical winding damper resistors are still good.

I don't believe he has any ringing issues so no need.
I was just showing him examples of what it looks like.

As far as I know, the remaining issue is the image being slightly off center.
I believe it is either because of physical adjustments being off or horizontal non-linearity where the image is slightly compressed on the left and stretched on the right.

Here's a recent image to remind us of the issues.
Image is being pulled up to the left.

http://www.videokarma.org/attachment.php?attachmentid=206753&d=1721586803

https://www.youtube.com/shorts/oIu4j7k1Qy8
The jumpy goes away after a while for the most part. I hope I didnt damage the yoke while trying to make sure it was tight against the crt. STill hunting for picture centering issue. I chickened out again taking the tube out. Probably this weekend when Im not pressed for time with help.
Tried again tonight j(friday), with help and I cannot get the crt tube socket through the yoke. Does it require a good bit of force or will that damage the yoke? Am I supposed to take off the focus coil first? Or just give up. Only thing I did was scrub the area around the high voltage part of the crt with wire removed.
TUNER is still dirty thats why the sound kept on going in and out. I can grab the main click knob and rotate counter clockwise and sound gets louder but IM stuck holding the knob slightly off click for louder sound. Im assuming that means dirty tuner. Even the contacts as seen through the side of the tuner look black/tarnished. Im using radio shack contact cleaner and lubricant. Says for tv tuners. Is there anything better?

I don't believe he has any ringing issues so no need.
I was just showing him examples of what it looks like.

As far as I know, the remaining issue is the image being slightly off center.
I believe it is either because of physical adjustments being off or horizontal non-linearity where the image is slightly compressed on the left and stretched on the right.

Yes focus coil position or an unwanted dc current through the horizontal deflection coils.

I still see the dark vertical bands on the left which could be due to a ringing in the first half of the sweep (inefficient horizontal damping?) or the damped flyback somehow modulating the video (poor power supply decoupling or filtering). This is something an oscilloscope would see.

Is the focus coil hole perfectly centered around the neck of the tube? Are the horizontal deflection coils capacitively coupled to the horizontal output transformer? If so a leaky capacitor would shift the image.

Focus coil is and isnt perfectly centered around tube neck depending on what im messing with. Trying to adjust yoke on tube and or taking tube out but cant due to tube socket getting stuck in yoke. Focus coil is slightly tilted horizontally but its tilted in the direction of which I want the picture to go or move I think but that could be just the yokes cap next to the focus coil causing the illusion of being tilted. Well if it is a leaky cap then it would have to be a mica one unless i have missed a paper cap. I have not removed the rectangular shield under chassis yet so if caps are hiding under there i will look. Notice the disc caps which have wax on them and they appear to be bubbly under the removed cover. Disc caps getting hot from going bad which everyone says they dont go bad hardly at all or is this ambient heat absorption. The heat baked 15k resistor measures 7.5k ohms so somethings parallel with it or it needs replaced. Also, under the video cover theres like 4 or 5 of 1k ohm resistors that are 1.2k and above in value with highest at 1.5k ohms. The Canohm resistor I suspect is also not too good and guessing this is the 6k ohm resistor and IM getting readings of 6.3k up to 35k ohms.
http://www.videokarma.org/attachment.php?attachmentid=206772&stc=1&d=1722082153.
http://www.videokarma.org/attachment.php?attachmentid=206773&stc=1&d=1722083397

I still see the dark vertical bands on the left which could be due to a ringing in the first half of the sweep (inefficient horizontal damping?) or the damped flyback somehow modulating the video (poor power supply decoupling or filtering). This is something an oscilloscope would see.


I'm not seeing any dark vertical bands at all. Are you referring to the test pattern image a few posts above?

Sure looks to me that there is sufficient width and the squares on the far right are not quite as wide as those on the far left.
That's why I keep saying it's a linearity issue and you need to adjust the drive/linearity/width controls.

Don't mess with anything under that metal shield. Those parts have nothing to do with centering the image.

Also, why are you trying to get the picture tube out?

trying to get picture tube out just to see how the yoke looks and possably if there was something keeping yoke from laying flat against tube. I did move the picture tube stand around a bit and it does have a small affect on the picture left or right. Not tons of adjustment but a small amount.
According to the tuner diagram, the contact strip of tuner is held in by two screws, can I remove this to clean that strip or is that asking for trouble?
While watching it play seems sound still goes in and out sometimes and sometimes I can adjust the 1st audio transformer and get it to come back louder or just better. Well, this time focus went totally away as well as sound for a bit. its like sound slowly gets softer and can even slowly come back. Focus knob is now to one end of it for almost sweet spot. Focus coil is near straight and centered to the tube neck. Sound just faded out with focus again. Wait 10 minutes with it on and sound with focus comes back. voltage at the yellow wire focus rheostat is about 280 and when sound with focus goes out this voltage goes up to 340 volts, wait a while and it goes back on. NOt sure yet if the resistors I just replaced are the cause or not, r215 should be 6k and a can ohm riveted to the chassis.

It's asking for trouble. Clean the exposed bumps on the tuner segments. The black is tarnished silver.

Here is what it looks like if you do open it up.
https://live.staticflickr.com/7028/6722857993_bf3b4fe979_z.jpg (https://flic.kr/p/bf5psH)

Oh is it easier just to take out the tumbler? and get to the contacts, or I can just keep on spraying and wiping.
Sound and focus solved: Dang audio output tube socket was dirty or tube wasnt in all the way, and I decided to check it because I thought I saw a focus/sound issue in troubleshooting chart that said check audio output tubes..Well if a tube goes cold, then whatever its doing fades out and when elememnt cooled it starts to work again. Bingo clean 6v6 socket with tuner spray, lube and yep. Here I thought I had screwed it up installing the sound area and b+ resistors. Now the sound just might stay level and not fade in and out at all.

Ni, it is not easy to remove. Spray cleaner onto cloth and wipe contacts. You're probably only going to ever use channels 3 and 4 so I'd concentrate on those.

Ok no idea why audio output tube filament was not staying on. Its not doing it now. Same as the 6bg6 tube where the filament was shutting off. Mess with it long enough and they quit doing it. anyway 2 things noticed were a 14000 ohm resistor that actually says 14000 aerovox on it which I think is supposed to be 15000 and measures 19000, plus theres 2 coils that look like they are corroding and should I be worried about the resistor value being over 25 percent off and the coils looking greenish? I see no reference to this resistor even in the changes being 14000 ohms and I have chassis run 18. Apparently sound keeps going from having it fully cranked and medium volume to blasting volume and having to turn it down. Was normal volume response with loud at full knob and I wanted to test the focus knob rheostat voltage center pin and the second I touched the center pin with meter it made popping noise and volume went to fully cranked medium volume. Wild, now focus is sorta near center of adjustent after using 2 of the 12k ohm 20 watt resistors in parallel for the 6 k can ohm.
http://www.videokarma.org/attachment.php?attachmentid=206774&stc=1&d=1722187466

Where is the resistor connected? Which coils?

the resistor is connected to the 1st audio I.F. T201 and the 6k ohm can ohm resistor riveted to the side of the chassis. The coils are connected in series and go to pin 8 of the 6ac7 tube. The coils look like they are each wound around a resistor. Coils are about the size of a dime and about thick as 2 dimes stacked in the photo

Yes, 15K. It's probably and old repair. I doubt it will make much difference if you replace it.
Those are peaking coils. The green is copper corrosion. Maybe the set was in a humid environment.
If they go open, the video quality will suffer. I don't know of any sure-fire treatment.

replaceable coils or just hope they dont go open? L304 33k ohm resistor and L305 1 meg resistor on parts list. I wonder if you could get a 250 microhenry coil and just take one end off of the resistors lead and put the appropriate resistor in place.
Side note: The focus is now at one end again of knob for adjustment. Amazing!
Weird: when I crank up the volume quickly......when its capable of full volume.....the picture tweaks a bit then goes back to normal.
250 uH coils are on evilbay, I bet if I took turns off I could get down to 150 uH for the 2nd coil.

You can probably find more correct peaking coils on mouser.

Has anyone ever tried replacing peaking coils? I haven't so can't offer any advice.
Not all inductors are created equal. There are other factors like "Q" and the winding pattern.
It's my understanding they wind the coils to dampen the "Q". It also means if the coil goes open, some signal still gets through.

You can probably find more correct peaking coils on mouser.
What qualifications do i need other than 250 and 150 uH. The schematic doesnt list the Q properties.

We don't know - that's the problem. It also should be wound around a carbon comp resistor.
Back in the day, you would just get one from Admiral or one of the other parts vendors (Merit, JW Miller, etc). Those days are long gone.

You go with what you have, scavenge from a parts chassis or experiment.

Ok so the fun begins with the oscilloscope and parts...i did order 250 and 155 and 160 coils off evilbay we will see. Makes me wonder if this is the vertacal jumpy issues that is intermittent.
So thats very interesting has to be wound around a carbon comp resistor so the coil must be like a choke.

Not, not at all. A "choke" block Rf from getting into a circuit. These coils help it get through by peaking the response at certain frequency ranges. The ultimate goal is to get around 4MHz bandwidth out of the video amp.

Just got my sencore ringer yoke and flyback tester in the mail, more fun. Hmmm 4 mhz bandwidth, interesting. so really the only way I would screw it up is if I used one with 2 low a resistor value in it for a peaking coil?

No, using a coil with the wrong characteristics could affect the bandwidth. I suppose you'll have to attach the resistor in parallel to the coil rather than have the coil wrapped around it. Not sure what effect that will have.

Seriously though. This is a really subtle thing and I really doubt you're going to notice much of anything either way without test equipment. Try shorting on of the coils out with a jumper wire and see if you notice any difference.

None of this has anything to do with your bigger issues. The focus control should not be at one extreme and you image is off center. I would not be surprised if the two are related. Namely, the focus coil is not mounted in the correct positon.

Sometimes focus is good sorta in center and other times not. Not mounted correctly i dont know other than wires out of focus coil come out of coil at bottom of it. Going to post pictures of current picture quality when i get home. As for focus i dont know how it can be good then not good...the sand resistor has been replaced.

I mean positioned correctly. Sorta good sometimes and not others is a big red flag. That means you have issues like an intermittent connection or short or tube that's going bad.

What qualifications do i need other than 250 and 150 uH. The schematic doesnt list the Q properties.

You need the inductance which is listed, and the resistance can be helpful. The RCA CT-100, 21CT55, and Motorola 21CT2 all use chalk peaking coils that rot open and I've had good luck using those 2 specs to obtain workable replacements off mouser.

Q might be helpful, but isn't essential. It's surprising how little effect shorting a good peaking coil has or how decent a picture can be with an original dead coil temporarily replaced with a jumper wire.

almost seems as if focus changes when I set chassis on it side while changing/replacing something. might try checking that connector again under load

..It's surprising how little effect shorting a good peaking coil has or how decent a picture can be with an original dead coil temporarily replaced with a jumper wire.

I've tried shorting a few just out of curiosity, and never seen it make the least bit of difference.

Welll i have an assortment of peaking coils now. So if they dont make a difference then im sure i can find a use for them...very fascinating if they dont do anything.
If the picture tube has was is shorted gassey i would think it would go wonky alll the time we are watching it..just seems as if i mess with it and focus changes...could be just dirty tube sockets

They do make a difference but you would need a good test pattern to see it. They improve the frequency response at the high end which results in finer image detail.

sound still goes low and high but not totally off. I replaced the two 15k ohm resistors in the audio section since my replacement had measured 14k and also the 14k resistor measured 19 k. Focus is now back, will see how long it stays. the voltage drop across the 15k to ground was measuring 25 volts before now its 155 volts. 15k to ground I put in there is 5 watts and it does get hot. When I turn off the set it gives a louder audio buzz for a second, not sure thats normal, but doesnt do it all the time. Basically still has weird gremlins hiding here and there.
If I pull any of the video tubes other than the first video tube, the sound gets much louder. Just pulled the 2nd video tube then put it back in and sound went almost out, then adjusted sound I.F. cans and got sound back but different position of 1st I.F. can slug. Its as almost as if these I.F. cans are iffy in adjustment.
YAYYYYYY. I think I found it. The 1st I.F. CAN terminal that goes to ground and a 330 ohm resistor if you move the terminal you get loud or soft sound. I dont yet know if I have to remove the can, replace the 330 ohm.resistor or what. CAn I remove the square shield, or does the can need desoldered and removed.
Going to assume the capacitor inside this can is 30 pf, schematic does not say. but has to be pico farads. I have zero guesses as to how accurate the 30pf has to be. the 2nd I.F. can has a 35pf in that according to schematic.
I have disc caps at 10pf. 3 of those would be 30 but dont know if temperature would make them change value or not. If not then I will just have to settle for a trimmer cap till I get correct ones and I might as well replace that 35 pf cap too.
Well, stuck 3 of the 10pf caps inside the can. Works and no crackly junk when the terminal of the 1st I.F. can grounded/330 ohm resistor to the 2nd audio I.F. tube anymore is moved/wiggled and I bet nothing will disturb it.

just blew the tv speaker trying to tighten d/a converter coax, the cone ripped away from voice coil form so I just reconed it. Had it sorta fixed with coffee filter and tacky glue but the cone itself was just tired and ready to expire so I just threw on a new cone.

turned tv on this morning and sure enough not my imagination as I thought before that the vertical was stopping, well, the vertical went away for 2 seconds and nothing but a horizontal line then comes back so thats probably my jittery height issue. Seems rock solid for a while then vertical jittery shrinky a bit then clears up but now Ive seen this several times where the vertical just goes away, but this time it was long enough for me to catch it.
Im not even sure what exactly the vertical section is, the schematic just says sweep section but I do remember shango and others talking about integrators so sweep must be vertical??? Keeps losing vertical, tried cleaning the 6k6 socket and thought that was it so Im just not sure whats causing this, might just have to let it fail. and if yoke then its a parts set.
https://www.youtube.com/watch?v=v-eeTfhPrMk

primary of vertical output transformer supposed to be 700 primary ohms and 12 ohms secondary is open....bummed now. Trying to figure out how to get a replacement since evilbay doesnt list them by ohms but by turns. turns ratio is weird 175/3. Not sure if I caused this or not.

Just picked up a thordarson 26s75 universal transformer but not sure it will work, but it was only 15 miles away so I thought Id take a chance. Well, its working now soldered pins 2 and 3 together for primary and used 1 adn 4 measured was 1.1k ohms. and for secondary I used pins 5 and 12 for 12.9 ohms.........its working. Now is thee something I can check to make sure I did it right so I wont overload anything or....if its working leave it alone? Wife and daughter say its clearer now with no jumpyness. I cheated and found another post on videokarma looking for a vertical output transformer for an admiral 20z1 so assuming these are correct parts interchange and listed part numbers admiral 70b24-1 a This transformer is quieter dunno if thats normal can hardly hear it. Focus is still mostly to one end of the adjustment lets see if it will stay.
stancore a-8112
merit a-3036
chicago TS0-5
thordarson 26s51
http://www.videokarma.org/attachment.php?attachmentid=206796&stc=1&d=1722806966

I still dont know the difference between vertical height and vertical linearity. Both seem to do the same thing....shrink or expand the vertical image top and bottom......watching mash with daughter...picture so far fingers crossed hasnt budged a bit. Just realized this was the first issue with this tv or any tv that I actually fixed myself kinda cool as I remember being handed a zenith 12 inch b & w by mom and dad and didnt know what to do as it had a vertial line down the center and of course I ended up wrecking the tv.

Yes, both do affect the height but linearity will also stretch or smoosh the top or bottom. Put up a test pattern while you adjust them. Do the linearity so circle is not egg shaped or squares are uniform. Adjust the height to fill screen

Ok will do another test pattern adjustment using usb test image....watched several episodes of tv programs aand rock solid...do vertical outpit transformers get noisy when going bad or is that just manufacture design differences becauseci can hardly hear the nos new one

Couldn't say as I've never had one go bad. I've seen a few that had already been replaced though. Maybe I've just been lucky so far.

I also need to replace the 35pf cap in 2nd I.F.can and i only have 34 and 36 pf...not sure those are close enough or do i need to go to mouser and order 35pf

It really doesn't matter as you'll need to do an alignment regardless. They were not precsion parts back then. Would not be surprised if the actual value was anywhere from 30pF to 40pF or beyond.

Ok cool if thats the case then for the 35 pf I could stuff in the 30pf I have now. Ok so if I have to align it because of vertical output transformer then maybe thats why it seems not as crisp for black and white as it did before the transformer was replaced. Id like to post up a picture of the video quality but my phone camera just makes the picture look like I have the brightness turned up all the way and washed out. I did notice the horizontal scan lines were closer together so maybe thats good.

Whoah there!
The vertical output transformer will have nothing to do with the IF alignment.

Regarding the capacitor in the 2nd IF, I would not sub 30 pf where 35 is specified. That's more than 10 percent off. Either the 34p or 36p you have should be good. What is wrong with the 35p that's in there now?

The 35 as well as the 30 in the 1st I.F. can is a made in wafer mica sandwich cap that is failing. Wiggling the terminal made my sound come back fully or partially. Same with the 2nd I.F. can when I accidentially touched the can and bumped it, the sound got slightly louder so I will replace the cap.

The 35 as well as the 30 in the 1st I.F. can is a made in wafer mica sandwich cap that is failing. ...

Thanks

These are the types of micas caps he's talking about hiding inside the sound IF cans.
They are not coated in anything so the silver tends to oxidize and develop "silver mica disease" from migrating silver causing intermittent crackles and degraded performance just like in a radio.

https://live.staticflickr.com/4134/4768026173_ec8bf8a159_z.jpg (https://flic.kr/p/8gko4P)

Whoah there!
The vertical output transformer will have nothing to do with the IF alignment.

Regarding the capacitor in the 2nd IF, I would not sub 30 pf where 35 is specified. That's more than 10 percent off. Either the 34p or 36p you have should be good. What is wrong with the 35p that's in there now?
My math was messed up so yes replace time.

I have never done an I.f. alignment on a tv. Not even sure i have the equipment. Oscope with freq counter yes. Heathkit signal gen yes but tv signal generator no

Most TVs you can do the sound alignment with an AM radio alignment generator. I tend to do sound alignment by ear. If the sound alignment is decent now and you change the caps in a can you should be able to realign the can by ear then do the next can.

What he said. Don't mess with the video IF but the sound is not so hard. Peak three of the coils for 21.5MHz. The last is for the FM detector "S" curve. Adjust that once so it sounds undistorted. You can get by doing it by ear.

I have the 20b1 chassis I dont have 3 coils just two of them unless Im not seeing the 3rd one.
http://www.videokarma.org/attachment.php?attachmentid=206802&stc=1&d=1722980148.

Primary and secondary. The are adjustable slugs on both sides of the chassis. Four in total.

Yes i discovered the secondary slug yesterday and not sure which to adjust first.as i didnt pay attention to which coil went to which terminals on the 1st I.F. can. I thought the adjustment was one continuious slug that was untill the bottom slug wasnt turning when i turned the top one. Going to guess by your picture bottom is primary

Read the alignment instructions. They identify which to adjust and in what order.

oh ok perfect.

sound is really good now. I guess its normal for the sound to have buzzing in it then when the picture comes on, the sound buzz goes away and perfect sound.
On to focus coil, I do have focus coil straight and not angled like before so Im wondering if I can get picture any sharper. Test pattern time I guess.

I think I might need to clean the cabinet glass or what ever it is. I dont think its plastic. Will windex clean it? Waiting on novus to get here for plastic screen. Installed chassis in cabinet and of course the picture is off to the left. Why I have to crank focus coil to extreme just to get picture centered is beyond me. Maybe I should crank it and call it is what it is. I have the converter box set to 4:3 full aspect ratio. Maybe this chassis was dropped and somehow its bent or needs the tube repositioned. Focus knob is almost to one end so by suggestion, focus coil is still off so if I get focus knob centered then adjust focus coil done. Maybe center the knob and adjust for best focus based on focus coil adjustment farther or closer to tube face? Messed with focus coil again, focus knob ect. focus knob comes in at almost full rotation.
Cant find my usb to put up test image. b & k 1210 test generator I bought has super crappy test image so needs a recap???
Screwed with focus coil and ion trap again and now picture is a hair to the right. Needs to go left a bit. Will post a picture of a test pattern if I locate my usb thumb drive. I guess moving focus coil back out did the centering trick but not sure how to get focus adjustment back in range and centered on knob.
https://videokarma.org/attachment.php?attachmentid=206856&d=1725727977

I had thought much earlier that focus was changing but its not. If only there were test voltages to measure. Unknown what voltage is supposed to be at focus knob rheostat center position

5 bucks says focus will be better 9nce i plug it back into 117 volts and not 125! Whei i put it back in cabinet i just plugged it in walll outlett. With a resistor adjustment i will be good

Maybe, but I doubt it. There had a wide operating range. 115-125 VAC should be fine. I think it's more likely it is not position correctly or there's a bad power resistor. I really banged my head with one of these and finally discovered a brand new 750 ohm power resistor in the focus circuit had gone open!

still trying to wrap my head around how the focus circuit even works. I have positioned the focus coil just about everywhere now. back and forth got me the picture to go left or right, but it took me this long to notice it. the Focus tap on the rheostat goes directly to the power supply 5u4. Oddly enough if the 6v6 tube heaters fail, the focus goes out totally as seen when the 6v6 tube socket was intermittent. I guess I need to come up with a better way to clean tube sockets.
https://videokarma.org/attachment.php?attachmentid=206857&d=1726004497

It's part of the power supply with some of the B+ going through it. Think of it like a filter choke. Any changes in the amount of current being drawn by the set will change the focus. When your 6V6 goes out, the current drawn drops, the electromagnetic field decreases and your focus goes out.

well that makes sense. I was FOCUSing on voltage measured across it when focus went out. So make it draw more or less current and IM good to center the focus control. I checked the 3k sand resistor that was replaced as welll as the 2200 ohm resistor which measured 2387 ohms so I dont think that is the issue

Oh now thats funny my schematic photo isnt in focus either lol

I replaced the vertical output transformer a while back so if thats not right.....that would draw more or less current and make the focus out of whack since the focus coil and vertical transformer are connected. I dont see any other resistors to check. The 5u4 doesnt have any resistors near it

well screwed this tv up again. I hear vertical running and I have 10kv at picture tube anode cap but no picture. I mayhave accidentially had meter in amps instead of volts when measuring across focus coil but not sure because negative meter lead wasnt plugged in. Anyway Now I have zero picture. So hoping I didnt permanently fry something making this tv a parts set. I do not know where to look now.
Going to guess the video section is dead, other than that maybe check for voltages. I already checked both fuses and since everythings lighting up probably not fuses anyway.
UPDATE:Im a moron! while tilting the chassis on its side to work on the focus and try a new vertical output transformer, I had bumped the ion trap! Now back to the focus issue. Focus knob when rotated almost fully clockwise is when focus comes in at roughly 80 volts across focus coil, so I need to figure out how to be able to increase focus voltage. Turning focus knob counterclockwise, the voltage drops and I can make the focus go way out of focus. 2200 ohm resistor connect to vertical out put transformer is 200 ohms higher. I need to get more voltage to the focus coil somehow. 87 volts is the max the focus knob will put on focus coil rotated fully clockwise! low voltage power supply is at 128volts and supposedd to be at 160 but focus coil runs off of high voltage so I dont know there.
Would a higher resistance in the high voltage 8500 ohm resistor make the circuit draw less current therefor throwing off the focus? Havnt tested yet but there are actually 2 purple dots that appear on the resistor when I turn it on. Resistor in question is r444 on the cathode of the 6w4 tube. Also the main transformer is making a funny noise but I cannot tell if its normal or not. I should try swapping rectifiers and the power audio tube as well.
https://www.videokarma.org/attachment.php?attachmentid=206883&stc=1&d=1727347973

Heck! there is a production change H for improper focus...see production change H grrr where is that? Tube installed for the 6v6 is a 6v6GTY....also might make a difference.

Do you have an image back?

What production run is your chassis? It should be stamped in a big orange letter in several places. 6V6 variations will make no difference.

Yes Image is back....knocking the ion trap while flipping chassis over made image go away compounded by the fact i turned the brightness knob down all the way and left it there while tweaking ion trap magnet so basically im my worst enemy here. Now image is back onceci figureed out ion trap and brightness were way off . I ordered 6v6 tubes anyway. I THINK chassis said run 18. It does have 2 fuses which the later sets had according to schematic. The focus was centered at one long ago but i must have done something to make it not centered unless maybe the vertical out put transformer going bad was the cause of focus adjustment going in and out of centered adjustment
I did find out that if you use the wrong power supply, the focus will be off so if you possably are using the 4 tube power supply in a set that required a 6 tube power supply that would cause focus to be at one extreme.

Have been checking resistors to find any way off and so far none. Only resistor acting funny is the horizonal linearity resistor when set is turned on. Two purple tiny dots appear on it very shortly after set is turned on.
Sitting here staring at the schematic and just not even understanding it. Both sides of the focus coil are tied together through a 3000 ohm resistor. So I have for possabilities low power supply voltage, resistor drifted high, other circuit somewhere not pulling enough juice through focus coil.
Update: Horizontal resistor that had two 20k ohm resistors and a 56k ohm resistor measured 55k so both of the 20k ohm resistors had opened up. Cause of focus being off? We will see.
AMazing! Focus came more twards center of knob adjustment. Since I do not have a 8500 ohm 25 watt or better resistor to stick in there I went with 3 30,000 and one 56,000 ohm and I dont know their wattage so Im not sure IM overloading them or not. The brown 25 watt resistor is just being used as a holder, its totally open. I have 10 of the 56k and 10 of the 30k ohm resistors 5 watts rated to play with so resistor booger soldering job in progress. Decided to go with 56k times 6 which gets me 9k ohms. Question is how much off of 8500 ohms and how far off affects anything. I know the specs say 7500 for a 10 inch crt, so will 500 ohms make a difference? Also guessing everything now has to be adjusted again, since now the ion trap moved twards rear of crt to get the good spot. Temp gun says around 200 degrees at bottom of these 56k resistors but much lower at the top of them and thats just weird but if they arent burning up then Im good and no more magical purple resistor eyeballs. Im done with screwing with adjustable open wire resistors as they damage and open up very easily!
So, tell me Im not imagining things because I had to move the ion trap magnet rearward after dropping from 55k ohms to 9k ohms on the horizontal linearity resistor r444.
https://www.videokarma.org/attachment.php?attachmentid=206889&d=1727549047
https://www.videokarma.org/attachment.php?attachmentid=206890&stc=1&d=1727557503