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Old 04-16-2012, 11:14 AM
6GH8cowboy 6GH8cowboy is offline
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Zenith 29JC20 restore

I have restored sets before and know the usual procedures and risks for the hardware. Assessing the task. The CRT is SO DONE and will be replaced. Purity ring assembly disintegrated and convergeng cloverleaf cracked. I slowly brought up the set fillaments only and all was well, brought up with HOT cap off still all is well. Brought up HOT cap on and in a dim room we have sweep and raster. With a signal there is a picture but the vert hold range is at the limit. and very poor horiz lock. Phase 1 is to repair any reasonable issues to restore proper operation. Are there any 'Known" issues with the sync for this beast? Phase 2 is to replace paper caps and black beauties and verify operation along the way. Also checking resistors as suspected or needed. Phase 3 adjust and setup.

This chassis is quite clean under the dust. It does give the impresion of being a high mileage set in a clean environment. Signal tubes are original, sweep tubes are not. No supprise there. There is no degausing coil in the set, that was a supprise.

What should I know about quirky faults for this chassis and why would be a splash of yellow paint on the power transformer?

http://i375.photobucket.com/albums/o...th%2029JC20%20

http://i375.photobucket.com/albums/o...V/IMG_1551.jpg
Color%20TV/IMG_1547.jpg
http://i375.photobucket.com/albums/o...V/IMG_1546.jpg
http://i375.photobucket.com/albums/o...V/IMG_1544.jpg
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File Type: jpg IMG_1544.jpg (62.6 KB, 77 views)
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File Type: jpg IMG_1547.jpg (74.3 KB, 85 views)
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  #2  
Old 04-17-2012, 11:38 PM
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reeferman reeferman is offline
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I used to work on a lot of these and loved them. It should be a good investment of your time and resources.
The yellow paint is to ward off evil spirits Who knows?
I believe I have a purity ring, and I do have a NOS cloverleaf so contact me if you are interested.
Good luck and have fun.
Phil

Last edited by reeferman; 04-18-2012 at 12:56 PM.
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Old 04-18-2012, 03:34 PM
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DavGoodlin DavGoodlin is offline
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NICE TV! I rarely saw those early Zeniths. They didn't seem to need all the maintenance RCA's did.

Would that be Zenith's first color set?
Are those two 5U4 tubes next to the transformer?

Good luck, maybe those beefy tube sockets need de-ox'ed. The tube chart has a sync path shown, maybe concentrate on those tubes first.
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Old 04-18-2012, 04:25 PM
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zenithfan1 zenithfan1 is offline
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Yep, Zenith's first color chassis......
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Old 04-18-2012, 07:48 PM
old_coot88 old_coot88 is offline
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There used to be an aftermarket gizmo to fix that busted 'cloverleaf'. It consisted of a bungee sized to stretch around the outermost periphery to hold the whole assembly snugly to the CRT neck. It should be easy to rig something comparable.
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Old 04-18-2012, 08:13 PM
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miniman82 miniman82 is offline
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Quote:
Originally Posted by DavGoodlin View Post
Would that be Zenith's first color set?
Yep, few and far between those are.

Quote:
Are those two 5U4 tubes next to the transformer?
Nope, 3DG4's.
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Old 04-19-2012, 02:28 AM
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mstaton mstaton is offline
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Damen also has that first model Zenith color set from 1961. 29JC20 chassis
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Old 04-19-2012, 08:41 AM
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DavGoodlin DavGoodlin is offline
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Quote:
Originally Posted by 6GH8cowboy View Post
Are there any 'Known" issues with the sync for this beast?
I successfully restored perfect vertical lock range on a 1965 Zenith 16" BW by replacing some of the resistors in the feedback loop. While the 29JC20 is no clone, it uses the 6EM7 for Vertical osc/out. There are resistors in the range of 560K that needed to be replaced with lower values per a service bulletin reprinted in the G/L Tab Books "Zenith Monochrome Service Manual" IIRC. I will see if I can find it and post.
Good Luck with that Beauty!
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