I spotted this set on craigslist tuesday, http://losangeles.craigslist.org/sgv/clt/930918497.html , already e-mailed and called the guy and told him I could probably pick it up on sunday morning. My Buick isn't running, but I think tomorrow I'm just going to go and rent a van to bring it back in. After seeing that "cat box" thread in the b/w forum I'm getting worried somebody might just show up tomorrow and have similar plans for this set. Anyway, I've never seen this particular chinese cabinet before, and it looks like it also has space command.

Strike while the iron's hot, Adam ! That's GOTTA be a Rare Byrd... Hope ya get it, get it home & it has Glorious Lollipop Color...(grin)

When I saw the topic heading, I thought this was going to be some abomination of a roundie picture tube inside a black-box cabinet or something (why someone would attempt that, I have no idea, but I guess anything's possible after reading that litter box idiocy). Adam, I hope you get it, since you obviously regard a nice old set the way it SHOULD be.

Doug owns a similar one to this but in black laquer and the restoration came out quite good. Keep us posted as i hope you get it. Definately a rare one.
-Tony

what a find!

Cool to have something like that in your back yard too :yes:

Hope you snag it.

Never seen the white one!!! What a find; Congrats Adam!

Charles

Thats got to be the rarest one! That cabinet is 100% original too, with the artwork painted on it. I have a 1964 brochure and it shows this model as the "orientale". This one has the '65 control panel though, so I bet it has the 25MC33 chassis. Its a space command 400. Maybe you'll be lucky enough to get the space command 400 color remote for it too. Those 400 color remotes seem as rare as the TV's. Great find, even better that it will be saved!

OK. I rented a van, and will be on my way to pick this set up in a few minutes.

I got it back here, now I have to figure out how to get it out of the van, it weighs a ton. The people I got it from didn't even know it had a remote, so no remote. They had their whole house looking like it was the mid50s-early60s. They had even been using this Zenith as a daily watcher until recently when they had problems with it. If it wasn't for the big modern 40" crt set they got to replace this one, in the living room you would have thought it was 1964.

Great news. Glad you saved it. Look forward to seeing the pics. And yes, it is a heavy unit. The cabinet is of extremely high quality on these, no particle board to be found anywhere. The one I have supposedly cost around $1000 new from what the grandson told be through his grandfather who originally purchased it in 1963.

Suprized it was actually in use until recently. Looks like it has the original CRT too. Probably a low hour set.

Figures on the remote being gone. Seems like they never come with the TV, yet we see thousands of them on ebay........

Well, Adam, PLEASE be careful & don't hurt yrself or the TV...(grin)

If it wasn't for the big modern 40" crt set they got to replace this one, in the living room you would have thought it was 1964.

Another CRT set....they must be intelligent :D

Chassis: 25MC33, Model: 6275UD. Here's the pics. It really doesn't look like it was used much, the chassis is very clean and it still has all original Zenith tubes. Also the 21FJP22 tests very good on all 3 guns. The guy I got it from said he only got it a few years ago, I'm guessing it was sitting not being used for most of it's life before that. No cataracts on the crt. The worst thing I see is where the paint came off in a few places on the top, also it is chipped on many of the corners and edges, it looks as if somebody at some point wasn't very careful moving it.

Wow, another Zenith roundie saved. That is in great shape. I bet it looks great when you get it going.

very interesting TV color version. but was produced by ZENITH or was made after by the owner?

That thing is gorgeous! Excellent save! I've never seen a white one, only the black with gold trim.

The cabinet was made by Zenith, they made two different chinese cabinets for their early color televisions that I know of, one was this white one with the designs on the front, the other a black one with just the gold striping on the edges.

Adam,
I'm glad you got it. At least we know its in good hands now. Cant wait to see a picture on it!
-Tony

Good job! You didn't happen to get any pictures of that living room, did you? (Well I guess that the owners might not have approved, but it sounds pretty incredible).

I thought about it but I didn't have a camera on me.

I pulled the chassis. The guy I got it from said that he was using it as a daily watcher for the past few years, until the breaker started going off when the tv warmed up, and this is when he decided to sell it. So the first thing I did was to check the diodes, they were good. Then the 160mfd electrolytics, not so good. I think I'm going to just replace all the electrolytics. I swapped the bumblebee caps out with orange drops this afternoon.(There were actually quite a few in this set - I wasn't expecting them in this late model of a set) I'll replace the electrolytics in a few days.

This is a real 100% Zenith produced at the factory. Zenith contracted with Drexel furniture for the cabinet, but it was all put together at the Chicago plant.

http://www.audiokarma.org/forums/attachment.php?attachmentid=120720&d=1228024739

Heat sinks on the power transformer? Must get pretty hot in normal operation, no margin if there's a leaky power supply cap...

Back then we were not worried about leaky caps. Also Zenith was not replacing transformers either! It was a well designed chassis albeit obsolete for the day. Zenith would not spend the money to "modernize" their assembly line which made an expensively built chassis.

Those transformers do get pretty hot, especially after watching the set all day like I do sometimes.

Oh yes... You burn your hand if you try to carry the chassis by the transformer after the set's been running. Same with CTC-16s et al. Those transformers hold in heat like a Thermos bottle!

Charles

Clean chassis. Did you work on it, or was it that way ?

I've heard that in the prewar era Zenith has trouble with transformers being underrated; I wonder if that was still on their mind?

I've heard that in the prewar era Zenith has trouble with transformers being underrated; I wonder if that was still on their mind?


Not sure, but I do know they had a bad reputation for failed field coils in the prewar radios, since the field coil was also the input choke for the power supply. Any load, such as a leaky filter, would overheat and open the field coil. Shoulda put a fuse!

Charles

That was the way the chassis was when I got it.

I recapped the electrolytics and checked all the tubes. All the tubes were good, and except for the damper they were all original. I would guess this was a very low hour set. The guy I got it from said he had it shipped out to CA from Kansas a few years ago. It probably saw more use in those few years he used it as a daily watcher than it did when it was new.

pics of the chassis after I cleaned it up and recapped: http://www.audiokarma.org/gallery/showphoto.php?photo=5473&size=big&cat=
http://www.audiokarma.org/gallery/showphoto.php?photo=5474&size=big&cat=

Very Nice! So how does it play??

It's not back together yet, probably won't be for another week or so.

I got this back together. The 2 problems it has are with the color and the power tuning. It works on all 3 guns, and does sync the color, but a resistor burned out on the convergence board when I first turned it on, I tried replacing it, but the convergence is still way, way off. I can't even get good separate red, green and blue lines when I flip the service switch. I mostly get a thick bright white line that won't even go away if I turn the controls all the way down. The power tuning is a mechanical problem, I hear something going in there when I flip the switch, but it doesn't actually move the tuner.

I picked up an SC400 remote off of ebay, it arrived today. http://www.audiokarma.org/gallery/showphoto.php?photo=5480

I made some progress on this today. I replaced 2 bad resistors on the convergence board, R192 and R193, if you're following along in the sams. Also replaced the 2 paper caps on the convergence board C124, C125. And replaced the selenium rectifiers (even though they tested ok) Now the convergence is basically good (it still needs adjustment, but it's not way off anymore) That solved one problem...
But the picture was still way too blue. And I still had a large thick blue line in the setup mode, red and green lines were ok. I started checking voltages at the crt. I checked the G2 voltages, all good. I checked the voltages at the cathodes, and they were ok. Finally, I went to check the G1 voltages and noticed that the blue wire was loose in the crt socket, I stuffed it back in the socket, and that fixed it. But I suppose I should take the socket apart (you have to drill out 3 rivets to get in this one) and solder it back on...
I still haven't looked at the power tuning.

I figured out what's wrong with the power tuning. The plastic gear on the end of the shaft coming out of the motor separated and broke in three pieces, allowing the motor to turn inside it without actually moving anything. I might try to glue it on there with some kind of heavy duty epoxy or something, but I don't have anything like that on me, I'll have to make a trip to the hardware store tomorrow. Here's a pic. http://www.audiokarma.org/gallery/showphoto.php?photo=5486&size=big&cat=503 You can see the upper part separated from the lower part on the shaft. It's not visible, but the lower part is also separated into 2 pieces.

Any way to get a part number for that?

The sams has a part number for the entire motor, but not just the gears.

I glued it back together, and it seems to be holding. I glued not just the plastic bits together, but also glued it all to the shaft, thinking that would make it hold together better. Like I said, it seems to work, but if I ever do need to replace it, now it won't come off so easily.

The range on the remote is greater than any other I've had, with the set in the livingroom, I can walk to the back of the kitchen (more than 20' away where there's no direct line between me and the set) and it still works. And I actually kind of like having the transistorized remote receiver, I don't have to turn it on and let it warm up before I can use the remote to turn on the set.

The reception on this set is also better when hooked to the antenna in comparison to my other roundies.

But, the uhf doesn't work at all. Turning the uhf tuning knob has absolutely no effect on the picture. Now I checked to see if there was power getting to the uhf tuner, and there was. I also plugged and unplugged the wire carrying the signal from the uhf to vhf tuner, and this does cause effects in the picture. So I'm thinking the problem has to be internal to the uhf tuner.

...

The problem with the uhf also appears to be mechanical. The tuner was frozen stuck, and rather than turning it, when I moved the controls, it just pushed the tuner at a slight angle to the gear turned by the control. So when I turned the knob, it wasn't actually moving the tuner. I won't know if there's anything else wrong until I take this apart, clean and lube it up so it turns easier, then put it all back together, but I suspect that this is it. I also need to replace the light bulb for the uhf.

I have the same problem with the gear being broken in my avatar set, I have a SC 400 black and white with a rotted cabinet that is to be the donor of a "new gear". If I run across two in my storage area that I am cleaning up this weekend, you can have the extra but there is no promise, I can't remember if I have two or not. When the motor shaft jumps out to turn the tuning gear, sometimes the teeth don't align and it breaks the gear that is now getting brittle with age. I wonder if there are any NOS replacements out there. Good luck with your set, it is a beauty.

I fixed the uhf, it was just the mechanical trouble with the tuner. But the uhf light wasn't going on, not because the bulb was bad, but from dirty contacts in the switch that turns it on.

I often wonder what will happen when the parts for these sets dry up. Now I may be in trouble if I need something like these plastic gears, but stuff like tubes are still readily available. But it's not like they're making more of many of the tubes our sets use. I want to keep using my big old color roundie consoles as daily watchers, but eventually we're all going to run out of 6GH8s and we'll all be in trouble.

pictures of the Zenith working...
http://www.audiokarma.org/gallery/showphoto.php?photo=5493&size=big
http://www.audiokarma.org/gallery/showphoto.php?photo=5492&size=big&cat=
http://www.audiokarma.org/gallery/showphoto.php?photo=5491&size=big
http://www.audiokarma.org/gallery/showphoto.php?photo=5490&size=big
http://www.audiokarma.org/gallery/showphoto.php?photo=5489&size=big
http://www.audiokarma.org/gallery/showphoto.php?photo=5488&size=big

Looks great! :thmbsp:

John

Thanks. Unfortunately it only worked that good for about a day and a half.
Now what it's doing is, when I first turn it on, it pops out of focus about every 2 seconds (out of focus so slightly that I can't really notice it unless there's writing on the screen). When it pops back into focus I see very briefly a single white horizontal line flash across the screen (not always in the same place). After the set warms up for about 10 minutes, it stops going in and out of focus, but the white horiz lines start flashing across the screen at a much faster rate, until it appears that there are several of them at once. (The lines aren't that bright, not really brighter than the rest of the picture, and they don't stay on the screen for long) After the set warms up for 30 minutes or so, the problem becomes intermittent and it will do it for several minutes, then quit for a few minutes, then start up again. Now I won't have time to work on this again till the middle of next week, but anyone have any thoughts on this?
My first thought is to start checking out what's going on around the horiz output tube, but then I've never seen anything like this before. There is no problem with horiz hold, width, linearity, etc. The vertical appears a little jittery in the first couple of minutes the set is on, then stops. But the vert sync is never weak, even when it first comes on. Vert size is fine, vert linearity is not totally perfect, but it's really close. The color is good, the problem occurs exactly in the same way on a color and a b/w picture. It does not effect the sound.

---

Check your focus lead where it goes into the crt socket. These are known to arc, crumble or corrode right at the pin in the socket. I had the same problem with mine and the problem was where the focus wire was connected to the focus pin in the socket was badly corroded. I fixed mine by taking the cover off the back of the socket. I then removed the focus pin and wire. After that I removed the wire from the pin, I cut about an inch off the wire because the corrosion had wicked back into the wire some. Then I cleaned the corrosion off the pin and soldered the wire and pin back together and reinstalled it. I also cleaned the focus pin on the crt and the crt socket while i was at it and checked for carbon trace. It took care of the problem and has been working great for almost two years now.

To get the cover off the back of the crt socket, get a 1/8 drill bit and just drill enough to remove the revit head. There are three of them. Pop the cover off and repair. After the cover is removed, you can remove the rest of the revit by pushing it through to the other side. To re-attach the cover, just find some small screws like you would find in a transistor radio or vcr and screw the cover back on using the original revit holes. Take your time putting the screws in to avoid cracking the bakelite socket. Some of these small screws have cutters made into the tips that will self tap the threads when installing. The good part about doing this is you can install the socket on the crt first and check for any arc's before re-installing the cover and coat with silicone or similar first. Remember that the wire leads just sit in the socket and use the cover to hold them in, so pay attention that the leads stay in the socket while your handling it with the cover off.
-Tony

Interesting... I had that similar problem with the blue G1 wire into the crt socket, but after I just shoved it in more, it didn't give me any more trouble, so I never took the socket apart. But later next week I'll try that first, then look more into the focus circuit if the problem isn't in the socket.

The corroded focus lead in the socket was exactly the problem. It was so corroded there was very little left of the sleeve the pin on the crt goes into. Also all the connections on the left side of the socket (all the blue and green and the focus) were broken right in between where the wire crimps on and the sleeve starts. I tried to solder everything back together, but it didn't hold very well. I eventually cut up a color crt extension cord I had and replaced the socket and wires going to it entirely, this worked.

The intermittent focus and white horiz lines flashing across the screen went away. The intermittent jittery vertical did not. It's very slight (only really noticeable on a still picture) and mostly goes away after the set warms up for a few minutes, so I'm going to leave it for now. I tried cleaning the vert hold/size/lin controls and that didn't fix it. I tried swapping the 6HE5 vert tube, and that didn't either (but the only spare I had tested pretty weak), so I'm going to order another one and try that next.

Despite all the little problems I keep having with this set, it still produces the best picture I've seen on a color roundie, and is easily in the running for best color picture on any set I've had.

I'm glad checking out the crt socket tip helped you. Its funny how i see this alot on Zeniths but not as much on other color roundies. Sounds like your heading down the home stretch now and glad its working pretty good for you now.
-Tony

I thought I had convergence trouble on this set, but it must be something else. I connected up the color bar generator, set it on the cross-hatch pattern, and the convergence is right on. Yet in certain images it looks like the convergence is off, see the left and right edges of the bumper sticker in the picture below. Any thoughts on where the trouble is?

nice zenith.that is not convergence causing your issue.it is in the demod coils.you may have to adjust them to get a good color saturation.i have a zenith with the same chassis.it had a similiar problem.the alignment of the color.just a slight turn of the coil and it is fixed.dont force it and never use a metal tool!!i know some of these guys will scream because of not using a signal generator but a slight turn should get it right.try to get something red on the screen such as a banner or shirt,etc.turn the coil until the red is fully saturating the image.a dvd or a fixed image so you can work.the coils are right beside your demod tubes.there is also a coil near the transformer that will need to be adjusted.good luck on this.

Adjusting those coils could make the same problem worse, but I couldn't get it to improve it much. I can go through the alignment procedure in the sams, it requires a color bar generator and a scope. Is there another procedure with a signal generator? If there's a way to do it with a vtvm instead of a scope that would be better, so I don't have to haul my tek545 down the stairs.

I thought I had convergence trouble on this set, but it must be something else. I connected up the color bar generator, set it on the cross-hatch pattern, and the convergence is right on. Yet in certain images it looks like the convergence is off, see the left and right edges of the bumper sticker in the picture below. Any thoughts on where the trouble is?

My Zenith with the 25MC33 chassis has this same type of color effect. I also have the slight vertical jitter too. It seems to happen nearer the top of the screen. It looks not so much like it is going to roll but that the height wants to shrink a little. I think this might be one of the design quirks in this chassis. It is still a great performer and I too feel that it has one of the best pictures of any color tv.

Two of my Zenith's 23XC36 and 23XC38 sets had that quirk.. Mine turned to be a vertical height and vert lin pot. Squirt them with deoxit..

Adjusting those coils could make the same problem worse, but I couldn't get it to improve it much. I can go through the alignment procedure in the sams, it requires a color bar generator and a scope. Is there another procedure with a signal generator? If there's a way to do it with a vtvm instead of a scope that would be better, so I don't have to haul my tek545 down the stairs.

What you're seeing is a chroma phase distortion. Proof is that it will disappear if you turn the color down to a black and white picture. Can be caused by alignment of tuner (least likely), IF (check sound trap), or chroma circuits.

I adjusted those demod coils a little either way with the color bar generator connected, and it didn't help. So I dragged the scope downstairs and followed what it said in the sams, I still didn't improve the problem. But I noticed the adjustment A23 (coil connected to the cathode of the 2nd chroma bandpass amp), did nothing. So I checked to see if the coil was open, it wasn't. I checked the 6KT8, it was good, tried swapping it anyway, no difference. So I started checking the voltages at that tube, plate voltage is fine, but pin 8 is about 100v low, pin 7 is only a few -volts (supposed to be -30). I check the resistor between pin 8 and the 240v B+, and it's ok. While at the 1st chroma bandpass amp, the plate and pin 8 read about 100v too high. But if I pull out the control which engages the color killer (or turn to a channel that's all snow so the color killer kicks in), all the voltages return to what they're supposed to be.

...
I just noticed it says voltages are taken with "no signal applied" at the bottom of the schematic, which could mean that those voltage measurements are only what they're supposed to be with the color killer working, as it would with "no signal applied", then the set may be working as it is supposed to, and A23 really just doesn't do much?

---

I tried turning the sound trap a little one way, then a little the other, didn't seem to make much difference. Then I tried connecting a dvd player to my ch 5 modulator instead of ch3. Then, if I had the set not on ch 5 but on ch 4, the reception isn't great, but this problem goes away. Fine tuning control doesn't seem to do anything at all, I'll have to take the tuner out and look at that later.

I don't know if adjusting the fine tuning can fix this problem, but I was correct about it not working. The rubber belt that's on there fits too loosely, and the shaft that it eventually turns is all gummed up and won't move. I'll have to take it apart further to see what's going on. But does anyone have a replacement for that belt, or know where I can get one?

It is true that this problem goes away on a b/w picture. If it comes down to IF alignment, I'm just going to put the set back together, and wait until later. I just acquired a complete set of the old RCA sweep/marker generators last month. But first I have get them in working order, and I'd want to try doing a few b/w sets before I messed with color.

A primary rule of good living: fix the obvious things first.
I would not fiddle with anything internal before trying the fine tuning.

Interesting focus problem, I have 2 RCA CTC10 having some focus problem only on the bright parts and sharp white details on the picture. The dark parts of the picture having low contrast are fine. Are they known to have focus or socket problems as well. I would not like to open the socket for no reason. Both sets behave the same way and I thought I had bad CRT's. They check good and one of them is a newly installed rebuilt tube.

I took the fine tuning mechanism apart, cleaned and lubed everything. Like on the power tuning, the plastic gear was broken and turned loosely on the shaft. I glued it back together, glue hardening now. The belt is loose, but it will cause the shaft to turn. But I don't know if it will slip when it's all back together and the has added pressure on it of turning those slugs in the tuner. The sams doesn't give a part # for the belt, anyone have that so I can try to order another one?

I'm putting this back together, and should have noticed better how it went when I took it apart. There's one clip I can't figure where it goes. :no: Picture below, arrow pointing to clip.

Ok I put this back together (minus that clip?), and it works, more or less. The belt will slip a bit when it hits the plastic gear tooth I tried to reconstruct from epoxy, but it will catch again after usually 1/2 turn. For now I'm putting this back together. I also have my 1950 RCA 6T65 console apart, and a 1956 GE portable chassis up on my bench, and I don't like having so many projects going at once. This is going to stay as is until I get either a new belt or a tuner to use as a parts unit to pull that gear from. It seems those plastic gears are a real weak point in these Zeniths.

Being able to adjust the fine tuning did not completely get rid of the problem, but it improved it a lot.

That clip would typically go someplace like on one of the shafts, just inside or outside one of the panels the shaft passes through. The shaft would usually have a smaller-diameter groove machined into it at that point. Look at each of the shafts and any other cylindrical moving part about the diameter of the middle part of the clip.