#1
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Philco 50T-1404
I need advice about the picture on my philco. First, there is a gray bar that is the width of the screen and is about 1.5" from top to bottom. It slowly moves from the bottom of the screen to the top of the screen. About 2 seconds after it is gone another bar appears and does the same thing. The other problem is a "hum" while listening to the set. I try to adjust the tuning knob to minimize the hum but when i do, the volume is minimized. Any advice would be appreciated.
The set has been recapped and works great otherwise. |
#2
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Check the signal source first. Does the bar appear on any other TV running from the same signal. If all is OK, then proceed as follows:
Determine if it is one bar or two. If two, electrolytic caps are likely. If one, a H-K shorted tube in the signal processing circuit is likely. Remove a tuner tube and see if the bar remains. If so, work through to the detector, removing tubes and observe the bar until it disappears, that is the likely shorted tube. If it is not a tube, then start bridging electrolytics until the problem is corrected. Last edited by Don Lindsly; 04-18-2011 at 11:45 AM. |
#3
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Also double-check to make sure that the negative terminals of all the electrolytic caps are properly wired. Some do NOT connect to chassis ground, and accidentally connecting to chassis can cause this kind of problem.
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#4
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Thanks for the helpful advice!
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#5
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I think I figured out the problem with the hum and the gray bar crawling up the screen from the bottom to the top as mentioned above. Here is what happened. I took the back cover off and used a cheater cord to turn the tv on and just observe the tubes and look for anything out of the ordinary. Everything looked ok. As I got ready to put the back cover on, I noticed that the picture tube brightener was resting on the crt neck so I used a rubber band to tie it to one of the picture tube braces as far away from the crt neck as I could . I turned the tv on and to my amazement, no gray bar, no hum, nothing! The tv has a great picture on it and the sound is the way it should be. I don't exactly how the picture tube brightener caused the problems but I am extremely happy that the tv works great now.
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Audiokarma |
#6
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Probably some 60hz hum being transmitted from the transformer in the brightener.
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