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Zenith Roundie Progress Update
As you all know I'm restoring my 1965 25MC33 Zenith TV. I thought I'd chronicle the restoration progress here for those interested. As of today, 18-May-2007 the set is in a state of disassembly. Scotty at Hawkeye called me to tell me that he is almost finished rebuilding my picture tube and that the process is going well. I should have the tube back sometime next week.
The cabinet is still at the refinisher's so no progress there yet. I have repaired the broken tube cap since I could not find a replacement. I found an adhesive that is like J.B. Weld for plastic and fixed the cracks. I am going to repaint the tube cap so the repairs are not so obvious. I have cleaned the bezels for the CRT and control panel. The paint is somewhat worn but I am just going to leave it as is. I fixed the magnetic closure on the control door so it no longer flops open. I have got most of the vintage crud off of the chassis and cleaned the front panel controls. I have replaced all the power tubes in the horizontal and HV section. I still have to clean both tuners, the yoke, the convergence panel and the automatic degauser. I still have some capacitors to replace in the power supply. I have to replace the flat lead wires from the antenna connections as well as many other little things. I have to repair a small crack in the volume knob. This set appears to have suffered from years of neglect. I'll post some pics as she comes together.
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Just look at those channels whiz on by. - Fred Sanford |
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wow , thats a lot of time and money into that set . Hope you keep it . After all that work it should be around another 40 years .
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I definitely plan to keep it. I do not have room to "collect" roundies so this is my one and only of this particular species. It is much easier to find places to use and store my collection of Bakelite tube radios than to accommodate a herd of console TVs. I have always wanted one of these sets so to me it is worth the effort. I just hope the end result is all I expect it to be.
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Just look at those channels whiz on by. - Fred Sanford |
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Here is a "before" picture
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Just look at those channels whiz on by. - Fred Sanford |
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Scotty at Hawkeye has finished my tube and has shipped it out. It will be at least two more weeks for the cabinet as the refinisher is busy. In the meantime I have been cleaning the yoke, legs, back cover, etc. When the cabinet is done, I want to have the rest of the set ready for assembly. Since I have to clean all the controls it will take a while to get all the adjustments back to where they should be. Fortunately I have the Sams so I have all the procedures for setup and adjustment. I really think this set is going to turn out well.
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Just look at those channels whiz on by. - Fred Sanford |
Audiokarma |
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Yesterday was a busy day for the old Zenith. I disassembled, cleaned and reassembled both the VHF and UHF tuners. One really has to admire the way these tuners were built. I cleaned all the contacts, removed the turret and lubricated the moving parts. Everything went together well with no pieces left over
I had to reglue the convergence magnet assemblies as they were starting to come apart. The chassis is cleaned up, all controls sprayed with Deoxit and the tubes polished with Windex. This set must have been in a smoker's home because there was brown crud on practically everything. Although I can't hook up the CRT and test it thoroughly because the cabinet is still not ready, I was able to hook up the tuners and speaker. The signal path seems to work (at least the audio portion) as I have sound reception on all channels. The vertical oscillator is running and its pitch varies with the vertical hold control. The high voltage section is operating and I was able to get almost 30 KV out of it. I did not run the HV for too long as I just had the probe hooked up. I know I need to adjust the efficiency coil. When the set is back together I will go through all the setup procedures in the Sams. When I first powered it up I saw a little smoke rising from an opening in the chassis. There was no component burning smell, however, just the smell of tubes and burning dust. I think that is all it was since it has stopped and careful observation reveals nothing out of order. I can't check the video and color circuits as I don't have a scope. I'll just have to wait for the cabinet and really test it when I can install the tube. The sound on this set is amazing. Even with just the small oval speaker, the set has more volume and richer tone than our 27" HDTV with stereo and BBE, etc. I will post another update when I get the cabinet back.
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Just look at those channels whiz on by. - Fred Sanford |
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---
Last edited by andy; 12-07-2021 at 02:12 PM. |
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Quote:
The stereo receiver below is a 1974 Pioneer SX-626 for the audio enthusiasts among us.
__________________
Just look at those channels whiz on by. - Fred Sanford |
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I got the cabinet back and assembled the set. It works!
I do have a question regarding setup. I completed all the procedures and got it looking great. Later I moved the set to where it will reside so I could give it a good run-in before I put the back and bottom covers on. In the new location, I noticed the purity was off. I corrected it only to have the convergence settings change. I have never seen a set so location sensitive. Modern sets, especially portables don't have this problem. Can anyone tell me what it is about these early sets that makes them this way? Or what is it about newer sets that makes them more immune to location changes? So far, I'm quite pleased with this set. It has turned out well. I suspect I still need a couple of tubes because when it is first turned on, the picture flashes and the brightness changes. Tapping the video output tube seems to aggravate the condition. Once it has been on for a while, it is steady. Occasionally the vertical will slightly shrink for a split second also. Here are a few pictures. The cabinet restoration came out well. I added threaded inserts to the screw holes where the bottom plate attaches and where the front cross brace (not shown) attaches. It works great off the ATSC tuner as well as DVD except the copy protection put lines in the top of the picture. Any way to get rid of these? I feel like I have finally joined the roundie club.
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Just look at those channels whiz on by. - Fred Sanford |
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That's a nice looking set. It's always good to see more roundies working. I wonder how many working roundies there are now, it seems every couple of weeks another one of us gets one going. I would think that the number of working round color sets might actually be rising.
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Audiokarma |
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Quote:
__________________
Just look at those channels whiz on by. - Fred Sanford |
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Great job Compucat. Considering the original condition, you brought it back right from "the brink". Hey, I see you found the correct VHF tuner knob! I don't recall hearing the story.
Where is the arc-shaped wooden brace that goes between the two front legs? It's in yout "before" shot. Don't leave it off, it's part of the charm (and maybe necessary for safety). As I recall, the one we had from 1964 to 1976 would split-second shrink the vertical, every time the fridge kicked in. There are filters that will remove the DVD lines. I have one that I built from a kit in 1986 or 87. Still works. Search this forum for macro or macrovision. I haven't touched my '66 since driving to Cleveland to get it. It's working original, but probably needs a whole resto before trusting it. I couldn't be more envious of yours. Excellent work! |
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Quote:
The round tube color Zenith has been the set I always wanted since I started messing with this stuff as a kid. My grandparents had one almost exactly like the one I have in 1974 and I fell in love with it. I only wish they had kept theirs but in the mid Seventies when it needed service, the TV repairman said they should just get rid of it.
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Just look at those channels whiz on by. - Fred Sanford |
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The purity issue you ran into is not uncommon. Not sure if yours has automatic degaussing (I think that was about the time Zenith added it?) but without it you really need the set close to where it will sit when you do the setup. In particular it should be facing in the same direction-moving it front to back won't cause problems. I suspect all the metal in that set, and the relatively inprecise neck components, would make them more susceptible than later model sets. Some of the wildest purity issues I ever saw were on a late model tv installed on a ferryboat. At the dock they turned the set on and it looked great thanks to the autodegausser, but as the boat turned things went all kablooey.
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Bryan |
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Those sets don't have any kind of auto-degauss IIRC, so that's why they are so easily thrown off.
I transported my latest roundie home 100 miles in the back of a truck, purity was only slightly off when I put it in place. The degaussing coil made quick work of it though. On the other hand, a past Zenith roundie I owned had such bad purity that I junked it after I couldn't correct it. This was back when I was young & dumb, and thought I was the only person in the world who liked old TVs.
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From Captain Video, 1/4/2007 "It seems that Italian people are very prone to preserve antique stuff." |
Audiokarma |
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