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-   -   Zenith Roundy Adjustment Issues. (http://www.videokarma.org/showthread.php?t=265209)

Arcanine 09-14-2015 06:31 PM

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

MRX37 09-14-2015 07:01 PM

Has the set been recapped?

SwizzyMan 09-14-2015 07:07 PM

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.

WISCOJIM 09-14-2015 07:38 PM

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

.

Arcanine 09-14-2015 08:53 PM

Quote:

Originally Posted by WISCOJIM (Post 3143589)
How much work did Tom put into this before you got it? Did he do a recap and any troubleshooting?

.

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.

WISCOJIM 09-14-2015 09:10 PM

Quote:

Originally Posted by Arcanine (Post 3143597)
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.

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.

Quote:

Originally Posted by Arcanine (Post 3143597)
It looks like Tom did indeed replace several caps, as there are several new style yellow ones installed under it.

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.

Quote:

Originally Posted by Arcanine (Post 3143597)
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.

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


.

Electronic M 09-14-2015 09:41 PM

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.

Arcanine 09-14-2015 09:53 PM

Quote:

Originally Posted by Electronic M (Post 3143604)
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.

Electronic M 09-14-2015 11:13 PM

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.

zeno 09-14-2015 11:54 PM

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:

Arcanine 09-15-2015 12:28 AM

Quote:

Originally Posted by zeno (Post 3143613)
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.

DaveWM 09-15-2015 08:45 AM

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.

oldtvman 09-15-2015 11:29 AM

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.

oldtvman 09-15-2015 11:37 AM

Here are screen shots of the same chassis you have
 
3 Attachment(s)
I always taught my techs, look for the obvious first, a dirty pot can cause lots of wasted time chasing around after intermittent problems.

DaveWM 09-15-2015 11:40 AM

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.


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