Hello all
While this is probably not a "bad caps" problem I thought I'd post here since there are many other threads on this topic.
Buoyed by my success with repairs to LCD monitors, I have been on the lookout for a faulty LCD TV to play with. Last week I was lucky enough (or so I thought) to acquire a 42" LG (42LH3000-ZA) with what I was told had been an intermittent fault which had becoming more frequent. I had hoped it would something nice and simple like dodgy power supply capacitors, sadly that does not appear to be the case.
The picture is mostly OK on power-up but after 30-seconds-or-so the brightness will fade, accompanied by a black horizontal line, and the picture displays a very slow motion blur - like a psychedelic video effect -evenly over the entire screen. The picture may also exhibit this problem immediately on power-up, with no delay.
Apart from the motion blur, the picture is quite clear. I have tried to capture the effect in the attached photographs.
I have fully disassembled it and checked all the connections. I have also carefully massaged all the tab bonds with the TV powered up but have been unable to identify any bad connections there. (The metal frame actually has some factory-fitted rubber blocks which press against the tape)
From what I've read, it sounds like a tab bonding or control board problem (or possibly main board) but since I haven't been able to resolve the problem by applying pressure to the tab bonds it seems unlikely - but not impossible - that's the problem.
My questions is: could a bad tab bond cause this problem across the entire display or is the control board (or even the main board) more likely?
Any advice gratefully recieved.
Thanks.
While this is probably not a "bad caps" problem I thought I'd post here since there are many other threads on this topic.
Buoyed by my success with repairs to LCD monitors, I have been on the lookout for a faulty LCD TV to play with. Last week I was lucky enough (or so I thought) to acquire a 42" LG (42LH3000-ZA) with what I was told had been an intermittent fault which had becoming more frequent. I had hoped it would something nice and simple like dodgy power supply capacitors, sadly that does not appear to be the case.
The picture is mostly OK on power-up but after 30-seconds-or-so the brightness will fade, accompanied by a black horizontal line, and the picture displays a very slow motion blur - like a psychedelic video effect -evenly over the entire screen. The picture may also exhibit this problem immediately on power-up, with no delay.
Apart from the motion blur, the picture is quite clear. I have tried to capture the effect in the attached photographs.
I have fully disassembled it and checked all the connections. I have also carefully massaged all the tab bonds with the TV powered up but have been unable to identify any bad connections there. (The metal frame actually has some factory-fitted rubber blocks which press against the tape)
From what I've read, it sounds like a tab bonding or control board problem (or possibly main board) but since I haven't been able to resolve the problem by applying pressure to the tab bonds it seems unlikely - but not impossible - that's the problem.
My questions is: could a bad tab bond cause this problem across the entire display or is the control board (or even the main board) more likely?
Any advice gratefully recieved.
Thanks.
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