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Old 04-18-2020, 02:52 PM
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Jeffhs Jeffhs is offline
<----Zenith C845
 
Join Date: Feb 2003
Location: Fairport Harbor, Ohio (near Lake Erie)
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Quote:
Originally Posted by Palinurus View Post
I recently bought a 1979 Zenith Chromacolor II (chassis 25KC45, model K2518M). When I tested it out it had no color, except for a bit of yellow here and there. I adjusted the grey scale and the yellow went away, but I'm still trying to troubleshoot the color problem. Was there a factory reset button on these TV's? I'd like to pursue the simplest possible solutions first.

I'm thinking that I may need another chroma module. Mine is numbered 9-89-H. I watched a Youtube video of a restoration of a 1977 CCII which had a module that looked very similar to mine. Were some of these parts interchangeable, despite the different numbers? Any help would be greatly appreciated. Thanks.
I wouldn't replace any components in your TV just yet. Older color TVs have a circuit called the "color killer", which cuts off the color circuits during b&w programs (this was when TV stations still broadcast black and white shows; the killer is all but unnecessary today, as all network TV shows are broadcast in color now). My best guess is the color killer control on your TV is set too high, causing the killer to work overtime, so to speak, that is, cutting off the color circuits whether or not it needs to. I would readjust the color killer control by first tuning your set to a blank channel, then adjusting the killer until the color just disappears from the snow on the screen. If this doesn't work, try replacing the color killer tube, as it may be weak or dead.
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Collecting, restoring and enjoying vintage Zenith radios since 2002

Zenith. Gone, but not forgotten.
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