View Full Version : Zenith roundie


LADR
08-04-2019, 05:55 AM
Ran across this set the other day on Facebag marketplace. I didn’t hesitate paying the $25 for it on the spot, now I just need to go pick it up, probably in less than a week or so. I’ll have more info and photos when I get it. As far as I can tell, it’s in great shape and it’s in a cabinet I really like. The seller didn’t try powering it up, but it probably at least somewhat works being a Zenith and all.

Electronic M
08-04-2019, 09:08 AM
Probably a 29KC20. If it has 3DG4 rectifier tubes than it is a 29JC20 Zeniths first consumer set. Very good sets when working properly.

kvflyer
08-04-2019, 01:55 PM
Good on 'ya, Mate!

AlanInSitges
08-06-2019, 04:02 PM
Gorgeous! And you're right: being a Zenith of that era you'll probably need to clean the tuner and then start watching it.

Electronic M
08-06-2019, 04:16 PM
Gorgeous! And you're right: being a Zenith of that era you'll probably need to clean the tuner and then start watching it.

These are old enough that you need to change the lytics if you plan to run it regularly....on my 29JC20 it sort of worked as found. I ended up changing the bumblebee caps and the lytics sections that tested leaky and ran it daily for a year or two...as I ran it more sections of lytics failed...in some cases taking out resistors as they died.:thumbsdn:.

They are good sets (the color quality is up there with the best), but the caps can be time bombs if you leave them.

John Marinello
08-11-2019, 09:54 AM
Probably sold it cheap because the picture was sideways... :D

LADR
09-02-2019, 03:35 PM
These are old enough that you need to change the lytics if you plan to run it regularly....on my 29JC20 it sort of worked as found. I ended up changing the bumblebee caps and the lytics sections that tested leaky and ran it daily for a year or two...as I ran it more sections of lytics failed...in some cases taking out resistors as they died.:thumbsdn:.

They are good sets (the color quality is up there with the best), but the caps can be time bombs if you leave them.

I’ll be replacing the caps toot sweet.

tom franco
09-07-2019, 05:37 AM
Nice zenith well built

freakaftr8
09-07-2019, 10:29 AM
Probably sold it cheap because the picture was sideways... :D

Omg I just got that... Haha!!

Nice set! How's the CRT check out?

LADR
09-08-2019, 07:50 AM
Finally got the set. Has 95% of its original tubes. The CRT was low but woke up after cooking for 20 minutes. Has a raster with snow. The audio is a very loud buzz. The fine tuning doesn’t work and that’s because the plastic gear that turns the screw thing thats on the contacts in the tuner is cracked. I took it off to glue it, but being me, I lost it. Do any of you know how I can get a replacement?

Sandy G
09-08-2019, 09:28 AM
One of these days, HOPEFULLY B4 I check out, I HOPE to go to that Majickal place where Things Go When They Get Lost.. My FORTUNE will have been Made... I will find things I've pondered & wondered over for YEARS, along w/stuff I've long since forgotten about..

Sandy G
09-08-2019, 09:31 AM
...MAYBE, just Maybe, I'll get re-united w/my long lost KV-7010U, my Feeble Mind, a few other things..

Electronic M
09-08-2019, 10:54 AM
One of these days, HOPEFULLY B4 I check out, I HOPE to go to that Majickal place where Things Go When They Get Lost.. My FORTUNE will have been Made... I will find things I've pondered & wondered over for YEARS, along w/stuff I've long since forgotten about..

I'd imagine all a us that have been decent people end up in the place all the cool lectronics that are no longer in the world end up after we've checked out..... It'd probably get to be a bit like hell if there wasn't junk for us to play with...

zeno
09-08-2019, 03:10 PM
I hope for a nice bench & lots of OEM parts. A 2 week backlog unless you bought it from us. I will teach my squaw how to do dial cords & mechanical
things & we will work together.

BTW I thew away some of those gears back abt 2010. All new in Zenith pkgs.
Who a thunk ? Looks like its the diaper pin style. Easy to find used. For now
you can set them with a small screwdriver. The grey scale looks great so I thinks you gotta winner.

73 Zeno:smoke:
LFOD !

I'd imagine all a us that have been decent people end up in the place all the cool lectronics that are no longer in the world end up after we've checked out..... It'd probably get to be a bit like hell if there wasn't junk for us to play with...

reeferman
09-08-2019, 05:25 PM
The fine tuning doesn’t work and that’s because the plastic gear that turns the screw thing thats on the contacts in the tuner is cracked. I took it off to glue it, but being me, I lost it. Do any of you know how I can get a replacement?[/QUOTE]

I think I might have one. Give me a few days, send me a PM.
Phil

old_coot88
09-08-2019, 06:34 PM
You can re-use that gear if it's split. Just degrease it and the shaft thoroughly, and epoxy back on. Done many, never had one fail. The teeth still engage just fine despite the irregularity where the split is.

LADR
09-22-2019, 10:56 AM
After reflowing the solder in the focus pin at the CRt, I now have nice stable focus. Tint range is pretty awful, and red seems to be too strong even though the screens are set correctly. CRt is pretty tired but very much watchable in a dark room. Still has this very loud buzz in the audio, and I can’t figure it out.

Robert Grant
09-22-2019, 12:07 PM
After reflowing the solder in the focus pin at the CRt, I now have nice stable focus. Tint range is pretty awful, and red seems to be too strong even though the screens are set correctly. CRt is pretty tired but very much watchable in a dark room. Still has this very loud buzz in the audio, and I can’t figure it out.

The strong buzz is Zenith's trademark sound identifying the set as a Zenith.

As for the tuner, just adjust the channel 3 tuning slug, since you'll always be using the set on channel 3 and changing the program using an external source (converter box, DVD, VCR, Roku, lo que sea).

LADR
09-22-2019, 12:15 PM
The strong buzz is Zenith's trademark sound identifying the set as a Zenith.

As for the tuner, just adjust the channel 3 tuning slug, since you'll always be using the set on channel 3 and changing the program using an external source (converter box, DVD, VCR, Roku, lo que sea).

I know the buzz your thinking of, and it’s definitely not that. Something is really wrong in the audio section. I didn’t mention, messing with the vertical hold effects the buzz. I already adjusted the FT with the tuning slug. I’ll probably end up using my UHF modulator, if I can’t find a replacement for the plastic gear.

Electronic M
09-22-2019, 12:52 PM
The strong buzz is Zenith's trademark sound identifying the set as a Zenith.

As for the tuner, just adjust the channel 3 tuning slug, since you'll always be using the set on channel 3 and changing the program using an external source (converter box, DVD, VCR, Roku, lo que sea).

If the modulator is putting out a correct signal, the IF/sound IF alignment is correct, there are no significant circuit issues and the buzz control is set correctly Zeniths are capable of excellent buzz-free audio.

One sei I have where the buzz control doesn't completely kill the issue I've found that on a tube RF modulator I have that has adjustable Audio carrier freq I can adjust that modulator to make good audio on the set (I may adjust its audio alignment in the future).

If the vertical buzz is in the speaker check the filtering, if it is there with the speaker disconnected then the vertical may have issues...Though some vertical systems just like to buzz more than others.

LADR
09-25-2019, 06:01 PM
If the vertical buzz is in the speaker check the filtering, if it is there with the speaker disconnected then the vertical may have issues...Though some vertical systems just like to buzz more than others.

It’s not there when the speaker is disconnected. I’ve ordered replacements for the filters and that should (hopefully) fix it.

zeno
09-26-2019, 09:26 AM
For the buzz try the AGC adj & buzz control. Next change the
detector tube. If still buzzes you can adj the detector AKA
quad coil. Dont go more than 1/2 turn & flag your stick so you
can go back where it was. If no joy check around the det.
Never had a component failure so no help there. A few sets went
out with just a light buzz on heavily white scenes. Newer content
& lack of OTA make make this a bit of a compromise.

73 Zeno:smoke:
LFOD !