matead13
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Aug 27, 2015, 12:16 PM
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Sony KV-XJ29M31 Brightness Problem
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Hi. I have a Sony KV-XJ29M31 CRT TV (Chassis Number: SCC-U44E-A) that works perfectly fine (tube colour is good, tube alignment is good, etc). However, the tube will sometimes darken itself. I find that if I give it a good whack to the side, it sometimes (very rarely) comes back to normal brightness levels. I find whacking it helps once the TV has been running for about 30 minutes (once it's warm).
I have disassembled the TV, and everything looks okay.
I have checked for poor solder joints.
The only thing I can think of is that the tube itself is bad, and one of the IC's is 'auto sensing' the voltage within the tube and compensating.
If that's true, it would be good to know what IC is handling that, and if possible, bypass it or feed it a resistance value that will permanently lock the 'auto sense' signal.
Any help would be greatly appreciated. I don't want to scrap this TV for what could be a simple fix.
If you need pictures or voltage levels checked, just let me know.
I do have an oscilloscope and I am competent with electronics.
Thank you.
- Matt.
(This post was edited by matead13 on Aug 27, 2015, 12:19 PM)
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