Zenith Roundy Adjustment Issues.
 

I will start off with, setting up a set like this, with so many fine adjustments, and procedures to adjust it; I am a little lost.

I did a basic adjustment per an adjustment video I watched on youtube last light for purity, and adjustment of the clover. This thing is all over the place.

The biggest issue seems to exist in the vertical section of the set. I can't seem to get it to straighten out correctly. The top is stretched and the bottom is squished.

Where should I start with parts replacement, testing, and so on to see if I can get a correct picture out of this set?

Here are some pictures of the set and what it's doing!

http://img.photobucket.com/albums/v4...pslwpkpbl5.jpg
http://img.photobucket.com/albums/v4...psqmdtk3ss.jpg
http://img.photobucket.com/albums/v4...pstci9ttzh.jpg

Has the set been recapped?

The vertical stretching of the picture is bad vertical linearity. Looks like the right hand side of the screen either needs to be degaussed or has a purity issue. You should just recap all of the electrolytics and the papers and any off value resistors.Pointless making any adjustments to the color and vertical linearity until the set has been recapped. I made the mistake of making the CTC-7 my second TV restoration... It was hell. Hopefully your zenith will cooperate with you more than my CTC-7 did.

How much work did Tom put into this before you got it? Did he do a recap and any troubleshooting?

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Good question. I am not completely sure. I'm probably going to attend that antique radio swap meet that happens this coming sunday by the air port in Milwaukee. It would be the first time I have ever attended.

It looks like Tom did indeed replace several caps, as there are several new style yellow ones installed under it.

I'm really kind of hoping someone there will be selling capacitors so I can just buy a whole bunch all at once, instead of ordering online or going to Chester's and getting a few here, and there.

Once I have a neat little stack of caps in my lap, I'm going to just recap the set entirely then attempt to align it.

The bottom has a large metal plate, that accesses the entire bottom of the chassis. I think I can just leave the Chassis inside the set, put the set on to it's side and just recap it that way, instead of having to unplug everything.

At least that's my hope. Save me having to heave a heavy chassis around. Just do most of the work in-set and go from there with the adjustments, see if I can get this set to perform even better.

See you there! If you don't find me, ask anyone to point me (Jim Menning) out. I don't think I'll be bringing anything down to sell at this one.

I'm hoping Tom will be there, he usually helps us out with the radio auction, and he's always interesting to talk with. Unfortunately he let me know recently he may be out of town that weekend.

Paul Dorobialski is usually there selling caps. Look for a large white van and lots of parts trays on his tables. If you head to the ARCI meet October 4th (not very far from you), look for Bob Piekarz. He sells caps by volume at very good prices. ARCI info: http://www.antique-radios.org/schedule.html Bob's website: http://www.radioantiques.com/



Anyone else interested in going to the Milwaukee, Wisconsin meet Sunday September 20th, see details at warci.org


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I left the orange drops (as I usually do unless the circuit one is in is malfunctioning, and all other parts have been ruled out), and the original lytics since most Zenith lytics of the era I've seen are still good.

The vertical was what I was next going to trouble shoot, but never got to, when I last stopped my restoration on it a few years back (I did tell you it had vertical linearity issues before you came for it)....I'd check all resistors between the integrator and the vert output transformer, and then change the orange drops and any lytics in that stage if it were on my bench and I was trying to fix that issue now.

I likely have enough new caps in my stocks to refresh the vertical stage....If you can't get them at the meet you can probably get them from me.

Yup~ I know what I was getting in too. I am using this TV to learn more about setting up and restoring old television sets like this.

I think I will take the option and just change the rest of the caps with new parts.

I meant to ask, did you test all the tubes in the set, as well? The Horizontal output tube looks pretty tired. It looks like a 6KD6 swaps with it, which I did manage to locate one.

I know I checked the color stage tubes (because when I got it it would not produce color since most of those were weak or bad, and thus were replaced), and IIRC I swapped the vertical tubes as a quick cure attempt (before I set it aside), and I may have tested the horizontal tubes when working on it originally (IIRC the original hot was down to air, and the osc. tube was dead so those and possibly the HV rect. were changed...I think it had a no HV issue I fixed by tube replacement before I replaced the bad B+ doubler cap).....I went over the tuner, IF, and AGC trying to fix the tuner when we were working on a deal (those were fine).

Some of those memories have 1-3 years of college classes written over them in the full (make that overfilled) hard drive that is my mind,....So I'm not certain I'm recalling them right. If you don't have a tube tester I could bring mine over and we could test them all.

First if you recap change just a few then test the set.
You can go nuts finding your own mistake if you make one.
Also dont change disc caps unless they look bad.
And dont take apart transformers to change them or change
ones across transformers, IF's etc. Only a last resort if a
problem in the stage.

Vert is often the intigrators. They are 3 legged & look like a
disc cap. Maked 87- & have a color dot. Dot tells you the
number so an 87-yellow is 87-4 etc. There are lytics in the
vert out cathode that go. They cause the bottom to pull
up. Also watch for bad high ohm resistors around the
V size control.

Screen shot shows good center conv., the rest is off. Purity
slightly off on right. Pix is too blue, could be set-up or the
blue gun is much stronger than the R & G.

BTW when you run the set on its side the purity will be
totally off. Thats normal.

73 Zeno:smoke:

Awesome. I will start looking in to these things. I want to see if I can straighten the picture out and get the vertical back to good condition.

I can say for sure as well, the V-Hold is very sensitive, I can't turn it one way or the other with out losing control and the v-hold goes all out of whack.

And as for the purity, I will do a full purity adjustment once I get the vertical working correctly, then I can do a convergence and get it all lined up.

And as for the blue, I did that. It's the way my eyes perceive the image. I always set my sets a little stronger in the blue direction when I adjust them. I think my perception of color is not perfect, so I adjust my sets to my taste. My computer monitors are set the same way. I always lean in the direction of blue being the general tone. Same for light too, I prefer the intense white LED's and such.

a few things

Zeniths used good caps, the only ones that may give trouble would be any bumble bees that may be there (maybe one across the line). Mass replacement is not advised. If you see any single electros esp if they are black with red paint, they can cause trouble. The cans typically are fine, esp if you did a soft start up. ONLY deal with parts that are suspect when you have a working set. Mass preventive replacement of caps on a nearly working set is not the way to go.

for vert issues, look for drifted resistors in the boost supply to the vert height pot and the feedback resistor from the cathode of the vert out back to the multivibrator.

check the electrolytic used for bypass in the vert out cathode.

replace the .1 elemenco (white ceramic if still there) that is used to filter the boost supply that is used after the height pot. Use a 2kv cap get them from mouser.

check the cathode resistor used in the vert out, 4700 1 watt.

Lin defects can be height defects that are trying to be compensated for by adjusting the Lin control too much.

clean all the controls and switches with control cleaner, a scope would be nice to look at the vertical waveforms, looks like your gray scale is also way off. Always work on the basics first and then move on to the color section. Power supplies are the first place to start.

Here are screen shots of the same chassis you have
 

I always taught my techs, look for the obvious first, a dirty pot can cause lots of wasted time chasing around after intermittent problems.

for sure check the easy stuff 1st, B+ line voltage etc...

oh and one more things, tubes can be bad, always a good idea to sub in a known working vert tubes. Sometimes forget they are not like solid state, can get weak.

First thing I'd do is check the B+ resistors in the vertical stages. Your setup may be similar to this:


http://www.videokarma.org/attachment...6&d=1420209652

indeed B+ and BOOST which is where the plate of the multivibrator gets its voltage. The reason for checking the .1 is if its even a little be leaky it will drag the plate voltage down, effecting the height. I am guessing you have the height pot maxed out?

Yeah. The height pot is cranked to max. And Vertical Lin. is cranked pretty high as well to get that much picture from the set.

yea so lack of height is the real issue, the linearity problem will likely resolve when you can set it correctly.

I would try in this order

check line voltage (should be at least 117ac)
check B+ voltage
if ok
try known good tubes in vert (multi and output)
if no change try each testing inbetween

check resistors mentioned esp the 48k or 68k from the boost to the height pot, this frequently drifts high.

check the screen and plate resistors per picards post

bridge the 100uf vert out cathode bypass

if still an issue comeback for more. My money is on the 100uf OR the boost resistor in series with the height pot. I would also recommend replacing the .1 elmenco's there are two of them, replace them both.

The pots could be bad but if the were I would think the adjustment would be jumpy and or not working. the best way to test a pot is to take it out of circuit and test with a analog meter. For now just hit them with some clean juice and work them some.

Okay so as a simple test, Tom was kind and provided me with the parts and tubes he'd removed from the set when he was working on it.

Just as a shot in the dark, I swapped out the 6JB5 tube and it did help a bit. The linearity is still off, but I don't have the set vertical height pot cranked to the max to fill in the screen, and the top isn't stretched out as much.

The bottom is still compressed, but the over all quality of the picture is better.

I decided to swap this particular tube, because I looked in the back of the set last night, and noticed it had a purple glow going on. The one I put in doesn't have that purple glow. I'm not sure what that glow is, but I have seen it before on 6LQ6 tubes inside of a Ham Radio RF Amplifier. When the amplifier was transmitting, the tubes would glow like that when they were driving RF.

I also did a very basic purity adjustment, and I was able to clean off that green splotch on the right side of the screen.

I also made the stupid newbie mistake and reached too far behind yolk assembly and got a shock/burn on one of my fingers. Whoops!

yoke burns are PAINFULL, much worse than HV, more current available I suppose.

Just remember that that purity and convergence setup are effected by sweep so if you go thru the effort to adjust those before fixing sweep, you will prob just have to do it again when/if you get the deflection working.

process in this order AFTER the set has been on for 20 min to warm up.

full raster (vert and horz)
setup linearity with test pattern
purity best reds (yoke back/center red blob/yoke forward to best fill red)
center converge (dots) focus for sharpness and keep the brightness down
dynamic converge (cross hatch)
grey scale

Yeah. With the set the way it currently is, I can't get a total convergence from it.

Because I didn't like how the tube looked, I swapped the 6JS6 Horizontal Sweep for a 6KD6 spare I had.

Another huge difference. It did not help the current issues but it did sharpen the picture up a ton. It always seemed slightly dim before and a little out of focus. The 6KD6 made a big difference.

Overall, other than the linearity and the blueish screen, you've got a winner there.

When I used to set up the screen controls with the service switch, I'd bring up red first to be almost dim... I did mine in a darkened room... Then the blue to make the red line purple, and then the green to make the grey. That should get you close.

Forgot to say, turn the color and brightness all the way down first.

Does anyone know what the difference with a 6JS6A and 6JS6C Horizontal Output is?

I didn't pay close attention to the letter and stuck in a C instead of an A. It works, but I wonder if that's why the tube it self acts weird until it warms up?

If you haven't already, Defo worth replacing C5 and C6 in your vert O/P stage.

Leccy-lytics lose value and dry up over the years, and in vertical timebase have a pretty hard life.
Any high value resistors in Height and Linearity control networks are also suspect.

Poor vertical lock could be issues in the sync-separator circuit, look for bias resistors of around 2.2M (Common issue on a couple of UK Hybrid TV sets, guess much the same applies if you have a Transistor doing sync-sep in yours)

A tip that was told me when I started out as a Trainee 40 odd years ago for setting up Any color TV....

Get the picture as good/perfect on Black/White First, Then worry about color after--Or you'll chase your tail!
--Its worked out pretty darned well during the last 40 years for me--so there must be summit in it!

The "A" version is rated at 28 watts dissipation, the "C" version is a little stronger, at 30 watts. Should work fine.

jr

Okay so per recommendation I am replacing the electrolytic caps in the vertical section.

I was able to get a couple from Chesters today but I have run in to a bit of an issue;

C5 has two sections in it that are rated at 475V, 50uF and 40uF respectively. Chesters only had caps that went up to 450. Same for Capacitor World.

Where would I source these from?

I use Allied or Mouser, they usually have the Panasonic ones that fit into the old cans.

second mousers. get the tall skinny ones, 105c

did you check those resistors in the Boost to plate of the 6BA11, 330k and 470k? and order up that .1 1kv while you are at it.

Those are going to be next.

I was not able to change the 475V sections like I wanted too in C5, but I replaced C6 and the smaller values of C5.

Progress was made. The image is sharper, converges a little better, and the image no longer buckles, collapses, or flexes on fast moving, or very bright images.

What about this? I know it's NOS but the seller has a good rating and claims it tested good.

It has all 3 sections I need of perfect values to what I'm needing in my vertical section.

http://www.ebay.com/itm/NOS-Sprague-...item1ea3cd139e

6917 date code? No way - I'd stay away from that - manufactured before Neil Armstrong took a giant leap.

I'd go with caps under the chassis, or restuff - Doug's step-by step is pretty helpful. You'd be surprised at how small electrolytics have become - in some cases, about 1/3rd the size of those made just 15 years ago...

Cheers,

Not only that, but $34.54? Wow!

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Not a chance! $30 to melt down your power transformer, not worth the risk.

Gregb

its really not that big of a deal to restuff.

My approach is to use a bone saw to cut the can off at the shoulder (leave the can attached, do not disconnect anything.

using a small pin vise drill, drill holes from the under side UP right beside the terminals. you can also drill right besides the mounting tabs. go right thru the can bottom (not the chassis).

fish the radial lead tall skinny cap leads down from the top, soldering the terminals and the grounds as needed.

double check work (polarity, voltage, value)

I can do a 4 section in about 15-20 min. The beauty of this method is it leaves the lead dress and any parts (like resistors or small disk caps) alone, greatly speeding up the process. I think it would take longer if I had a new twist tab cap to install.

I don't bother with replacing the can tops. if you like you can dig out the guts from the top and use some alum duct tape to reattach.


the only real impediment to the process is if you lack good access to the cap with the saw. Also you should cover the chassis with paper towels taped down before sawing to keep the alum chips from gertting everywhere.


demo of the restuff
https://www.youtube.com/watch?v=kh2yurjt5sM

be very careful with cans that are mounted to insulating mounts. These are found in voltage doubler and as in the video, where the chassis is not the ground.

this is why I like to always attach the caps EXACTLY as the can so the check the can to confirm the polarity (yes there are time when the can may be the positive side). Make sure you connect up the cap so the neg is tagged the same way the can tab is.

Okay to the scrap bin with the idea of a NOS cap.

I went looking for axial lead caps of the correct values. The 40uF is easily found at 500V

The 50uF @ 475 to 500V is impossible to find in axial lead, however. I have found on multiple sites, 47uF @ 500V

It's only a hair below 50uF, would this be safe to use? I'm sure it has to be better then the old wore out can that's in there.

Because if I can sub the 50uF with the 47uF, I can just buy and install two of the same kind to replace the can below the chassis. I already know I can sub the 40uF with the 47uF and still be safe.

Actually.

http://www.ebay.com/itm/Qty-2-50UF-6...3D320606792940

At 10 bucks a cap, and the seller is in the US, I'll just purchase these. The seller has a 100% feedback rating and some vintage radio sites make mention of them on a positive light.

These high voltage filter caps are a massive pain in the neck to find.

I can't imagine subbing the 40uF with a 50uF will hurt anything on a filter cap like this. I subbed a 20uF 400V with a 100uF 450V once in a tube radio just to test it and see if it worked, and it did, and still does.

If you can get more green gain, the pictures will look better, especially football games. Or back off on the red and blue gains, assuming you'd still have a watchable image.
http://www.videokarma.org/attachment...4&d=1442334955

This is what I am currently getting out of it.

http://img.photobucket.com/albums/v4...pszm7bhtax.jpg
http://img.photobucket.com/albums/v4...ps7znulkyr.jpg
http://img.photobucket.com/albums/v4...psvnrrnhyz.jpg

I'm hoping to see more improvements after I completely have taken the vertical filter cap out of line and replaced it with the new ones I ordered up today.

I'm aware blue is set a little high. According to my eye doctor I don't see blue as well as others, so when I make adjustments, I tend to set blue a bit higher for my own tastes. The color looks perfect to me, but it may look heavy on the blue to others. Personal preference with how I set my TV's, computer monitors; Any display really.

Still smashed at the bottom and stretched at the top. After I replace the filters then I'm going to check resistors and make sure they're correct tolerances.