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Old 04-11-2018, 01:59 PM
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TheUniversalDave1
 
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Zenith 20Y1C50 broken again

Yesterday, I decided to put the original picture tube back in my 1968 Zenith 20Y1C50 set, and everything went perfectly. Not a single headache, and I had the thing back up and running in an hour, and only half an hour to do purity and convergence. So I get up this morning, and it still works, but when I go to adjust the brightness, the act of simply touching the brightness control kills the luminance. There is very little luminance/brightness. Almost like the potentiometer is stuck at 1/4 of the way up. Again, it was working perfectly when I put it back together yesterday.
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Last edited by TUD1; 04-22-2018 at 03:01 PM.
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Old 04-11-2018, 07:01 PM
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Electronic M Electronic M is offline
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Bad control, tin whiskers in control, bad connection to control...Those would be my first 3 checks.
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Old 04-11-2018, 08:55 PM
old_coot88 old_coot88 is offline
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Loss of luma can be caused by dirty service switch or H-K short in CRT. Hope it ain't the latter. Tap on CRT neck to see.
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Old 04-11-2018, 09:20 PM
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I moved the service switch back and forth and saw no effect, and tapping the CRT neck didn't do anything either.

Also tested the CRT and it tested "adequately usable".
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Last edited by TUD1; 04-11-2018 at 10:12 PM.
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Old 04-12-2018, 12:31 AM
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Crisis averted. A wire, probably soldered in by hand, came loose from the brightness control. Set is working again.
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Old 04-13-2018, 10:42 AM
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So glad it was an easy fix!
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