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  #166  
Old 11-25-2008, 08:44 PM
andy andy is offline
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Last edited by andy; 12-07-2021 at 04:28 PM.
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  #167  
Old 11-25-2008, 08:49 PM
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Loctite-now there is a company with some good products. I have some of their super glue at work in a unique container that works great and is less of a mess. You squeeze-in on 2 tabs built into the bottle.
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  #168  
Old 11-25-2008, 09:38 PM
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Loctite is what i use in the container Bryan describes. I get about a years use out of each bottle and have never had a mishap with it. I never had it plug up either. I guess it has to do with the design of the container. Now that i said that i havent had any problems, i probably now will
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  #169  
Old 11-27-2008, 06:12 AM
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Quote:
Originally Posted by drh4683 View Post
I started to pull it apart this evening. As you can see in the photos, the TV was backed up against a forced air supply duct. This obviously blew a ton of dust into the TV. Grey dust luckily, it was not a smokers set. I can handle that. I was able to tape the tube layout diagram back together. The loose screws were the top screws that mount the TMA to the bezel. Why those were removed was beyond me. Its a simple key slot mount. Thats why I think the home owner pulled it apart, and rubbed his arm against the side of the cabinet while doing so tearing up the layout diagram.

So far, most of the tubes are shot. Since I never had a 25CC50, I was suprized to see a not so common zenith tube. They used a 6JG5 for the 3.58 mhz oscillator which Ive never seen. Thats a one of a kind tube that you never see in other zenith color sets. Zenith almost always used a 6GH8 for that. I can name every tube used in all the color zenith chassis in my sleep except for this one. The 6LB6 is so dead the filament might as well be open. This is very alarming when I see a dud horizontal output. It means it was running way to hot, and this was a replacement sylvania so something is definitly wrong. The belfuse for the cathode is missing too as well as the 6JK5 regulator. Something strange happened to this TV, yet to be determined.
Doug,
I have a 25CC50 in a sort-of danish modern style cabinet that's my main living-room set. It was my parents' 1st color set they bought in late 1971, and has been in near daily use except for a year or two around '95-'96, before they gave it to me. I did all the service on it, until I graduated college and moved away in '83, and then they ran it until it wouldn't go no more, and replaced it with a Sony in '95.

When I got the set, the CRT was shot and most of the tubes tested bad. I had another 25CC50 in a metal cabinet with a good rebuilt CRT, but with several other issues, so I sacrificed that one to get my parents' console working.

Anyway, the 6JG5 isn't the 3.58 oscillator. It does use a 6GH8 for that. The 6JG5 is either the burst amp or the chroma bandpass amp. The other tube is the 6E(H/J)7. The rest of the chroma processing is done in the IC on the plug-in module.

On that chassis, the heaters for the damper and HV regulator are wired in series (probably to keep the HV from coming up if the regulator tube is removed). There should be a label on the HV cage door with two specific regulator/damper pairings because of different heater currents. If your set has a 6DN3 damper, you'll need a 6JH5 regulator (2.4 amp heaters).
I've had two problems with the horiz. sweep in the metal-cased set I had. One of them was a 33 or 39k 1 or 2 watt resistor going to one of the plates on the 6U10 horiz. osc/disch. tube going intermittent, and causing loss of drive to the horiz. output. This would toast your 6LB6. I replaced it on my console as a preventative measure. Also, the VDR in the horiz. output circuit went open, causing insufficient width but not overheating anything.
(Sorry I don't have exact values on these parts, I'm going from memory, and I haven't been inside my set in almost two years.)

Another problem with this chassis is the 1.2 or 1.5 Meg resistors around the HV adjust pot drifting out of tolerance. They are 5% tolerance, and when they drift out, you won't have enough range on the HV adjust pot to get 25kV. If you run out of range on the focus control, you'll have to replace the focus divider. If the original one is still in there, it's probably bad by now. It crosses to an ECG HiDiv-4, discontinued years ago.

Also, I've had trouble with early '80s NOS compactrons cracking where the base is attached to the bulb. I've had it happen on the HO, damper, and regulator tubes over the past few years, both GE and Sylvania-made tubes.
I figured that's from sloppy maufacturing, as by that time those tubes would only be used for replacement purposes.

Good luck with your set, if it has a good CRT it'll have that typical excellent Zenith picture.

Mike
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  #170  
Old 11-27-2008, 09:53 AM
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Thanks for the tips mike. I just checked the chart, and this tube is the 1st color amp. Actually, I started looking for one this morning. ive got thousands of NOS tubes, not one single 6JG5 though, not even in boxes of loose used tubes. It must have been one of a kind for this chassis. I do have a 6DN3 paired with the 6JH5.
I put the set back together last night to try it out, knowing that the 6JG5 needed replacement. I powered it up, and got about 5 seconds of a raster, but bloomed away and the 68 ohm resistor on the 9-49 module went up in smoke, as did a 2.2k under the chassis from cathode to ground of the 6GH8 oscillator. Didn't pop the breaker in the cathode of the 6LB6 though. I useds a sans-a-fuse in its place just in case it wants to pop, and I don't waist good bel-fuses should a problem arise in troubleshooting. I tested the 6JG5 again, and now its got an H-K short, but I can't see how a short there could fry up those resistors if in fact that was the cause for the failure. I checked lead dress, but I did not disturb anything under the chassis. Tint and color leads are proper too, as I had the tuner out. Nothing shorted out there either. Very interesting problem here.

The troubleshooting will need to wait as I have to buy a tube on ebay and go pick up some resistors.
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  #171  
Old 11-28-2008, 06:37 PM
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Went to an estate sale today only because the flyer advertised "several TV's."
Passed on the 5" b/w am/fm still in the box for 5$.
Passed on the GE mid 80's 13" color portable for 10$, although it was in good shape, just a common garden variety tv.
Passed on the hideous Philips 13" color tv with the analog clock under the CRT - not much of a bargain at 35$.
Passed on the 32" Sanyo - too much at 100$ - would have gladly given 50 for it though.
Passed on the 20" RCA Colortrak Plus - although I should have bought it for the niggardly asking price of 27$
Did snag the 27" Sanyo for 40$ with a perfectly good cart/stand and the original remote. Usually find these beat up and missing the remote and sitting on a worthless particle board stand. Didn't really need the beast, and definately not a fan of Sanyo quality, but the price was right.

The find of the day though was a panther on a log tv lamp in perfect condition. Damn thing even had a working C7 bulb. It looks mean as hell sitting on the blonde 1963 Zenith b/w console I got from Doug.
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  #172  
Old 11-28-2008, 09:54 PM
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Doug, I have a 6JG5 to spare if you need it. NOS Zenith. Send me a PM with your address, if so.
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  #173  
Old 12-31-2008, 10:52 PM
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The end of 2008

This concludes another successful year of vintage TV finds at the estate sales. 2008 was a good year for me, many good things happend this year, a promotion in my career and also some extremely freightening moments as well that could have easily ended my life. Lets hope to have another good year with good health. Even though we are losing analog TV in 2009, we alteast have our collections, and hopefully a job and family most importantly. Lets keep finding these old TV's (or any vintage electronics for that matter!) Happy new year everyone!
Doug
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  #174  
Old 12-31-2008, 10:59 PM
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Cheers to that Doug! Happy new year! And good luck collecting in '09!
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  #175  
Old 01-01-2009, 01:08 AM
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Happy New Year Doug and cant wait till your first estate sale find of 2009! These are among my favorite posts in the tv forum.
-Tony
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  #176  
Old 01-01-2009, 06:52 AM
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Sandy G Sandy G is offline
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I wonder how many more old veterans are out there & will get "dumped" this year simply because "They won't work no more..." 2009 could be a banner year for us Mad Monks...
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  #177  
Old 01-01-2009, 01:03 PM
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I wonder who will be the first to start "Estate Sale Finds in 2009"???

Charles
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  #178  
Old 01-01-2009, 02:18 PM
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Can't wait. Hope the TVs keep popping up.

2009 may very well prove to be *the* most important year in TV collecting, since analog sets will be dumped by the truckload due to the transition to digital.....
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