Greetings,

This set is available locally and advertised as "non working." Can anyone ID this set? Is is worth saving? The price is right-- free :thmbsp:

Thanks,

Clark

From the knob layout and green halo, it's a Zenith. A really nice Zenith. Go get it!

Late '60's-early '70's Zenith that's worth saving.

That's a '68 or 9. Nice picture and great performer. Go save it!!

Great, thanks for the feedback! I was hoping that it was a Zenith. This will be my first vintage color set. I'll post when I've hauled it home.

-Clark

If you pass on getting it, I live near milwaukee and love zenith sets enought to save that set(especially if ti is free).

Tom C.

A great first set! Some of the finest TV sets ever built, and that's no lie.

One of my old sets in my late teens that I fixed and later sold and I wish I had kept it was a Zenith similar to this. Was a 1967 Zenith 20Y1C38 chassis. What a great performer that set was.My uncle had the 1969 combo set with a solid state IF module and plug in color demodulator ic. Performed great too. I think that one was a 16Z8C50 ? chassis.The original crt survived 16 years of daily use and it got a Channel Master replacement in 1985 which was still going strong in 2000 when he replaced it with a bigscreen Toshiba.

Around the late 90s I saw a nearly identical set to my old Zenith (could have even been the same tv) being used as a table for one of the cashiers at an auction house in Bridgeville DE. I practically begged them to sell me the tv but they wouldn't.It probably hit the dump when they went out of business.:tears:

a keeper for sure.run as fast as you can to get it!

Looks like it's missing the channel selector knob, but these are/were common sets and I'd bet you could locate one.

This model has the convergence controls behind the speaker grill making for easier adjustments. Should be the 16Z8C50 chassis which is listed under Howard Sams 1074-3 dated 1-70.

A good, solid performing set!

Well, unfortunately the owner has not returned my calls so I may be too late:pity:

Maybe they're just out of town for a while...

-Clark

persistance is the key. I one time chased a free set for weeks. turns out the owner got so many bozos calling (aranging meeting times and then not showing up) that they just stopped responding to calls. eventually after several trys I got thru, then went out and got it immediately.

Also we overplay our hands on these sets, remember its just junk to 99.99% of the people out there, so its not like they are on pins and needles just waiting to respond and spend energy fooling around with them.

I guess I spoke too soon. I just got a call and I'm picking it up Saturday :banana:

It's the "mother in law's" set, so I could get no further details. I'll post a bunch of photos when I get it. I'll need lots of guidance getting it running!

-Clark

:yes:

:thmbsp:

Nice set! IDK but it looks awfully like a 20BC50. Im probably wrong.

Around the late 90s I saw a nearly identical set to my old Zenith (could have even been the same tv) being used as a table for one of the cashiers at an auction house in Bridgeville DE. I practically begged them to sell me the tv but they wouldn't.It probably hit the dump when they went out of business.:tears:

Was that the place behind the antique mall? I bought a bunch of radios one night at the sale there; they had a nice Zenith porthole console but I had to get home for some reason and couldn't stick around. They had a huge Westinghouse combo from the late 50s that must have been the nicest bw set Westinghouse ever built. Between the store and the auction that thing sat around for 5 or 6 years. Last I saw it they had moved over by the back doors and I figured the next step was outside. Often wondered about that thing.

I have a Zenith out in the shed that I think is from somewhere in the 69-71 era. I would give it to somebody if they were to come get it. Not much different from this one.

Was that the place behind the antique mall? I bought a bunch of radios one night at the sale there; they had a nice Zenith porthole console but I had to get home for some reason and couldn't stick around. They had a huge Westinghouse combo from the late 50s that must have been the nicest bw set Westinghouse ever built. Between the store and the auction that thing sat around for 5 or 6 years. Last I saw it they had moved over by the back doors and I figured the next step was outside. Often wondered about that thing.

I have a Zenith out in the shed that I think is from somewhere in the 69-71 era. I would give it to somebody if they were to come get it. Not much different from this one.

Yes it was behind the antique mall. I bought records quite a few times at that auction but never saw really old tvs except that Zenith but then again I wasn't partucularly looking for them then. The RCA CTC 25 will take enough room if I can squeeze out some room after the 1956 Admiral b/w console goes to it's new home saturday. I wouldn't mind looking at the Zenith if it's easy to get to.Maybe if I get a bigger place when I move out of here I might want it. The Zenith is the better set but the RCA has more nostalgia attached since my dad's tv in my childhood was an RCA CTC25.

It's here!

I owe my friend Mike big time for helping me get this sucker home. It was in the second floor bedroom of the mother-in-law's and we were both drenched in sweat by the time we got it to the first floor. We manged to get it in between thunderstorms in my '71 Olds Vista Cruiser station wagon-- how appropriate!

The model is Y4528 and the chassis is 20YIC38. The CRT is a 25XP22 that is a replacement Sylvania. It test good overall, with the red gun being a little weaker. The chassis is very dirty but appears to be unmolested. I did an initial inspection and clean up. I powered it up slowly on a variac and was rewarded with a a raster and sound:banana: The picture is shrunken and monochrome but obviously the vital organs are good! The EC cans stayed cool to the touch. Marty59 is right, the convergence controls are behind the speaker grille-- cool!

Every control in the thing is very dirty so the next step will be to pull the chassis and clean things up. The are photos of when I first got it home, after a little clean up, first raster at 90V, the CRT emissions test (on green) and the raster after some tweaking. The only knob missing in the main tuning knob which shouldn't be too hard to find (I took the other knobs off for transport).

I;m really psyched to have my first vintage color set -- and it's a Zenith:thmbsp:

-Clark

For some reason I had a feeling this was the 20Y1C38 chassis and not the slightly newer 16Z8C50 and I was right. Mine had a a slightly plainer cabinet but you got practically the same set I had when I was starting out with tvs.

Wish I had kept mine.:sigh:

JCFitz, I just reread your earlier post and you did indeed nail it as a the 20Y1C38 chassis. I'm glad to know that it was (is) a good performer. I'm very pleased that the CRT has useful life left and the the fly and yoke are OK. I'll post more pictures soon.

-Clark

I haven't had much time to work on the set but I did finish giving it the once-over. I replaced several weak or shorted tubes, including the burst amp. Each time I was hoping it would restore the color, but no dice. The SAMS for this set is 927-2. Anybody have a scan of this before I shell out $22 to SAMS?

I cleaned the VHF tuner, which is a high quality turret type. The UHF tuning was frozen. I did get it moving but it's still quite stiff. The VHF fine tuning seems inoperative. It's activated by pressing in the spring loaded outer concentric knob around the channel selector. It engages and turns the gear on front of the tuner but it make no change to the tuning. The AFC switch on the front panel also seems to have no effect. I thought that maybe the absence of color was a fine tuning issue but I couldn't get color from my color bar gen when tweaking the output frequency. Clearly, I need to pull the chassis and start looking for bad caps, etc.

Cosmetically, I'm really happy with the shape that it's in. The cabinet is cherry veneer and solid cherry and it's in excellent shape. I found a temporary tuning knob that works until I find an original.

Here are some more photos:

-Clark

I'll snail mail a copy to you for five bucks, if you want. I really don't want to put the time into scanning all that!

Thanks Bryan, that would be great. I'll PM you to work out the details.

-Clark

Thanks to Bryan, I now have the SAMS for this set. One look at the schematic and I realized that in a boneheaded late-night move I had completely missed checking the 6GH8A reference oscillator tube. I had checked every other tube and forgotten to check the most notoriously wretched tube in the set! A quick sub with a 6U8A (I'll put in a 6EA8 soon) and this is what I saw:
http://i1216.photobucket.com/albums/dd366/IsthmusTV/P1020032.jpg
http://i1216.photobucket.com/albums/dd366/IsthmusTV/P1020033.jpg
It's got some purity issues, but it's looking pretty good overall. The white speckled noise in the picture is a result of my cheap "RCA" DTV box. And to think that up until now I had been blaming my Philco 49-1140 :no: I suspect its crappy switching PS.

Last weekend, I inspected the chassis and replaced several electrolytic and what appear to be paper caps. Here's a shot before I did anything. It appears to be all original.
http://i1216.photobucket.com/albums/dd366/IsthmusTV/P1020019.jpg
Those look like paper caps, don't they? I replaced the brown ones. The white Elmenco is rated at 1KV so I'll need to order a replacement for it and a few others. Fortunately, the vast majority of caps are ceramic disc.

Next, I'll check the HV and HOT cathode current and adjust the efficiency coil. I'm looking forward to getting this set back in tip top shape and watching some period-appropriate movies on it. They certainly don't build them like this anymore!

-Clark

I agree on those caps-I haven't run in to many of that exact style. Might as well get them out of there while you have the chassis loose.

You really need the cathode current test adapter socked for the zeniths. What a pita without it.
Replace the white ceramic caps, they get noisy and leaky and cause the vertical to jump.

I wish I had seen this, i have the pdf sams...whatever. I also have a bunch of zenith service bulletins. If you have any specific issues let me know and i will see if its addressed.
I have 2 sets with that chassis. The HV regulation can be a PITA too. Super robust flybacks though.

I sold these new in 1969.

Things continue to improve by degrees. I tested the old caps that I removed and none of them were leaky. But I think I'll go ahead and replace the rest of the paper caps anyway. ctc17-- thanks for the advice. I see what you mean about the HV regulation and measuring the cathode current. I think I'll leave the ceramic caps alone for now since the set is working pretty well. Here are a couple of screen shots from the Anchor Man DVD:
http://i1216.photobucket.com/albums/dd366/IsthmusTV/P1020042.jpg
http://i1216.photobucket.com/albums/dd366/IsthmusTV/P1020046.jpg

The vertical size is still inadequate and there is a green to purple hue shift slowly drifting vertically through the picture. I think it's time to change the electrolytics in the PS! Both cans run cool, but I don't want to push my luck.

Thanks for the help.

-Clark

It looks like you need to tweak the convergence.

That set will make a nice pic. the elmencos will cause vert jitter. The brown plastic caps may be fine, I dont recall have to replace them. I am pretty sure I have a thread in here on that chassis, it was one of my 1st color sets.

The fine tuning may have loose gear on the little gear that engages the tuning slugs in the tuner. If you can see the gear on the outside turning and nothing is happening in the fine tune then thats it. its an easy fix, but you will have to do some dissassy on the tuner. a drop of super glue will fix it. But do take it apart as trying to glue it in place will surely end poorly.

The UHF will need to have the big drum reamed, it swells up and gets stuck.

If you have an old school cap tester you can save yourself a lot of needless cap replacement. Just pull one leg and test for value and leakage.

What dave said on the tuner, but I usually slide the cracked gear off, clean it up really good and jb weld it back on the ribbed shaft. Every zenith I own has that gear cracked.

How was the cutoff on that crt? Were you able to get up to high in the red? What kind of emission do you get at 5 volts? (i have the same crt tester)
That red and green color bleeding can be caused by a semi week crt.

What dave said on the tuner, but I usually slide the cracked gear off, clean it up really good and jb weld it back on the ribbed shaft. Every zenith I own has that gear cracked.

How was the cutoff on that crt? Were you able to get up to high in the red? What kind of emission do you get at 5 volts? (i have the same crt tester)
That red and green color bleeding can be caused by a semi week crt.

I wonder at what age the fine tuning gear started cracking and the UHF shaft swelled up? I sold:nono::tears: my 20Y1C38 in the early 90s and no problems with the tuning mechanism. Worked great.

Thanks everyone for the guidance. You guys are spot on about the tuner. I'll disassemble it and do it right. As for the CRT, I'm afraid it is on the weak side. I couldn't get the red channel up to the "gun bal" line on the meter so I don't know how valid the emissions test is. The green and blue guns seem OK. I didn't test the CRT specifically at 5 volts, but emissions dropped pretty rapidly on the life test. So, I'm not sure how much effort I want to put into this set if the CRT tired. On the other hand, it is making a very watchable picture that seems to be getting better all the time. I do have an old Heathkit C-3 cap checker that I can use.

I may not have much time to work on this set for a few weeks, but I'll post my progress when I do.

Thanks again for the help,

Clark

I have worked on hundreds of this model since they were new. The AFC control does work and make sure it is "OFF" when you are fine tuning it. It will be difficult to fine tune if it is on. It was more of a selling point and fun to demonstrate when it was in the showroom. If it does not fine tune, the little gear that engages the strips in the tuner is split and needs to be replaced which was a common fault in these sets. I may have a NOS one.

...If it does not fine tune, the little gear that engages the strips in the tuner is split and needs to be replaced which was a common fault in these sets.
Yes, that was true even when the sets were just a few years old. We always just epoxied the split gear back on, after first cleaning it and the shaft thoroughly. Worked fine and never had a call back for that problem. Bill(oc)

After being busy with other things, I'm now preparing to replace all the electrolytics in the PS. The cans are rated at 475 Volts. Would it be OK to use caps rated at 450 Volts? It seems that you really pay a premium for electrolytic caps rated at higher voltages. For my Emerson 637 which also had EC's rated at 475 V, I used 500 V caps from Antique Electronic Supply. I later read on ARF that 450 Volt caps would have been fine. Any thoughts?

Thanks,

Clark

Is there a reason to change the caps? Is there a problems or is it just about the popularity of recapicide? I have several of those sets and the cans are good in all of them.
You need to use the 500 volt ones if you have to change em.

Most likely you will create more problems than you will fix, if it works leave it alone!

Hi ctc17,

Thanks for the reply. That's what I was wondering, too. I hate to do a recap if it's not necessary. The cans don't get warm but there are some issues with the picture that might be caused by the power supply: Both the height and width are inadequate (even after tube substitutions) and there is a ripple in the picture that drifts slowly upward. Also, there is a really annoying hue shift that coincides with this ripple. I have subbed most tubes, but not all, so it could still be a tube issue or a leaky cap elsewhere.

Also, I suspect that the 6HS6 HV regulator may be weak, even though it tests OK (I don't have a sub for it). If I turn the brightness up too high, the picture dims and begins to fade away. I have tried two different HV rectifiers. I haven't attempted to measure and set the HV yet, though. I know that this set has HV regulator issues but I haven't heard what that translates to in terms of performance problems.

-Clark

Hi ctc17,

Thanks for the reply. That's what I was wondering, too. I hate to do a recap if it's not necessary. The cans don't get warm but there are some issues with the picture that might be caused by the power supply: Both the height and width are inadequate (even after tube substitutions) and there is a ripple in the picture that drifts slowly upward. Also, there is a really annoying hue shift that coincides with this ripple. I have subbed most tubes, but not all, so it could still be a tube issue or a leaky cap elsewhere.

Also, I suspect that the 6HS6 HV regulator may be weak, even though it tests OK (I don't have a sub for it). If I turn the brightness up too high, the picture dims and begins to fade away. I have tried two different HV rectifiers. I haven't attempted to measure and set the HV yet, though. I know that this set has HV regulator issues but I haven't heard what that translates to in terms of performance problems.

-Clark

Ok, for some reason I thought you said it had a perfect picture. Thats sounds like a reduced value power supply capacitor. You can test them and change the bad ones or replace them all.
They reason they are rated so high voltage is because the voltage is real high before the tubes warm up and load it down. Ill look at the schematic when I get home.

I would replace all the white tube type caps while you have the chassis out.

I bet C1A and or C2A is open.
If it was my set I would jump a 100uf at 450 volt axial accross the bottom. You can test them easily with an esr meter or speaker and audio source.

Insufficient vert height can be caused by low boost voltage, drifted resistors in the height circuit, and a bad height pot. What's HV measure?

I ended up ordering all the electrolytic caps as part of a larger cap order I was placing anyway. I know that I'll use these caps for something if the cans in the Zenith turn out to be OK. But I think I may try your suggestion of jumping C1A and C2A temporarily with 450V caps just to see what happens. I also ordered a bunch of tubes, including a new HV regulator and an HOT.

And miniman82, thanks for the leads on the insufficient vertical. I have yet to measure the HV. I plan to do that this weekend.

-Clark

the white elmenco HV caps (1kv IIRC) should be replaced I think there are two, one up by the damper the other near the front of the chassis, part of the vert, if the vert is a bit jumpy esp. HV regulation with the 6HS5 is not as good as the older 6Bk4, I can see where they made quite a few changes in that circuit over the models. I understand it is better as far as no X ray radiation (loads down the FLY at much lower voltages), but I will take the 6bk4 shunt tube over it every time.

Be very carefull handling the chassis, all those point to point parts can be easy to move with the uncovered bottom, and likely to short something out, I had this happen on some of the larger disk caps, they have relatively thin leads and it does not take much effort to move them around.

I finally measured the HV and it's a measly 16-19 KV. The HV adjust seems to have no effect. Would that likely be the shunt regulator? I swapped out the HV rectifier with no change. Of course, the tube that is out of stock on my order to vacuumtubes.net is the 6HS6 (the HV regulator). The one I have tests OK but as we all know tube testers can be very wrong. Clearly, all is not well with the HV on this set.

Also, I re-tested the CRT and now emissions from the red gun are even lower (in the white area between replace and good). Oh, well. I'll proceed with the PS recap when my order arrives and see where that gets me.

Thanks again for the help,

Clark

Check it with the regulator tube out, i dont think this chassis has the safety to protect against that. If it goes up look for bad resistors. Its not a HV shunt, it regulates the HV by clamping the 900volt boost. There is no danger of running the set with it out.

I had one of these that had a bad resistor and was causing the regulator tube to clamp super hard. It melted the regulator tube.

It could also be due to low b+ from bad caps.

Thanks for setting me straight on the regulator circuit. I got the cap order yesterday so I'll recap the PS and go from there. Unfortunately, I probably won't have time until the 4th of July weekend.

Cheers,

Clark

I finally found the time to work on this set. I replaced all the electrolytics in the PS. The 500 V Illinois Capacitor caps I used were too large to restuff the cans with so I mounted them all under the chassis. The caps were clearly the main issue with this set because it is now making an excellent picture with full width and height and no ripples in the picture. The HV now measures 25 KV. Here are a couple of screen shots:
http://i1216.photobucket.com/albums/dd366/IsthmusTV/P1020089.jpg
http://i1216.photobucket.com/albums/dd366/IsthmusTV/P1020092.jpg

I still need to check the HOT cathode current and touch up the convergence. I'm also hearing static clicks coming from the vicinity of the HV rectifier. It doesn't sound like arcing. It sounds the same as the static discharge you hear right after powering off the set. I've tried cleaning everything but I couldn't get to the underside of the HV rectifier tube socket. Does that white plastic cap just pull off?

Anyway, I'm very pleased at the nice picture on this set and it appears that the CRT has plenty of life left. Soon I'll tackle the broken gear on the fine tuning control.

-Clark

That looks beautiful! Nice job!

looks great!cant beat those old zeniths for a crisp.sharp picture.

I think of all of these I uncrated and set up back in 1968-69!

Yesterday, I finally got a replacement 6HS5 HV regulator thanks to a ham radio friend. The old one tested weak. The picture is now rock stable with changing brightness, not like many newer, cheaper sets. Last night I did a side-by-side comparison of the Zenith and my Sony Bravia LCD HD set. The colors were surprisingly close on the two. But I think the Zenith had a slight edge on flesh tones. Not bad for a 43 year old set!

-Clark

Great, thats a good solid chassis, prob be running strong in anohter 40 yrs.

Finally got around to checking the HOT cathode current and adjusting the efficiency coil. It took me forever to locate the jumper to remove to insert the ammeter. There is no mention of where it's located in the SAMS folder. Of course, I found it only after I cut a lead to the coil to measure the current :nono: That's it next to the damper tube. It was hidden behind that wire bundle.
http://i1216.photobucket.com/albums/dd366/IsthmusTV/P1020100.jpg
As is, the current was about 205 ma. After adjusting the coil it's just over 200.
http://i1216.photobucket.com/albums/dd366/IsthmusTV/P1020105.jpg

I was able to adjust the HV to the SAMS specified 24.5 KV but the pot is just about out of range (on the low side). I replaced the damper tube which helped somewhat. Here's a shot of the recapped chassis. I also changed out all the 1 KV rated tubular caps:
http://i1216.photobucket.com/albums/dd366/IsthmusTV/P1020102.jpg

I managed to snap off the shaft of the horizontal centering pot. Anyone got a lead on a replacement? I'll have to check the value of the pot. Meanwhile, the picture looks great and the set is a big hit with my friends and family :tresbon:

-Clark

200ma looks good. nice set.