Hi all,
I have recently been trying to save a Philips 50inch plasma TV with a faulty Ysus and lower buffer board. I have found and replaced two faulty MOSFET transistors on the Ysus board, and bought a replacement (second-hand) buffer.
On fitting the parts and powering up, the TV worked perfectly. For about 3 hours. Then the picture went fuzzy, with some ghosting and sparkling, interspersed with very bright flickering of the picture.
I turned the TV off and allowed it to cool for about 30 mins. When I turned it on, it was OK again until it warmed up, when the same problem returned.
I checked the voltages on the power board (VS and VA) and made sure they were correct. The TV continued to show the fault for around an hour. Then suddenly the picture returned to perfect clarity. It stayed perfect for around an hour, then with an audible 'pop' the picture disappeared completely. Sound continued. I switched off and left overnight.
Upon inspection, i found a blown IC on the lower Y buffer. I removed the buffer, and swapped over the blown IC with a good one from the old buffer. I also checked the Ysus board, and was surprised to find all the MOSFETs to be ok. So i fitted the repaired buffer, and switched on. Again the picture was perfect for a couple of hours. Then the same fault occurred, although as of yet it has not blown the IC. I have now switched off, and decided to ask on here what I should do next? My inclination is to fit a complete Ysus repair kit even though the components all seem ok when tested with my multimeter. I cannot see any signs of bulging on any of the caps on the Ysus board.
My question is, What could be causing the fault to occur when the boards get hot? Is there a particular component I should be looking to replace? Has anyone else had this same fault before?
The Ysus part number is LJ41-05120A.
The buffers are LJ41-05121A (UPPER) and LJ41-05122A (LOWER)
Thanks in advance for your thoughts
:-)
I have recently been trying to save a Philips 50inch plasma TV with a faulty Ysus and lower buffer board. I have found and replaced two faulty MOSFET transistors on the Ysus board, and bought a replacement (second-hand) buffer.
On fitting the parts and powering up, the TV worked perfectly. For about 3 hours. Then the picture went fuzzy, with some ghosting and sparkling, interspersed with very bright flickering of the picture.
I turned the TV off and allowed it to cool for about 30 mins. When I turned it on, it was OK again until it warmed up, when the same problem returned.
I checked the voltages on the power board (VS and VA) and made sure they were correct. The TV continued to show the fault for around an hour. Then suddenly the picture returned to perfect clarity. It stayed perfect for around an hour, then with an audible 'pop' the picture disappeared completely. Sound continued. I switched off and left overnight.
Upon inspection, i found a blown IC on the lower Y buffer. I removed the buffer, and swapped over the blown IC with a good one from the old buffer. I also checked the Ysus board, and was surprised to find all the MOSFETs to be ok. So i fitted the repaired buffer, and switched on. Again the picture was perfect for a couple of hours. Then the same fault occurred, although as of yet it has not blown the IC. I have now switched off, and decided to ask on here what I should do next? My inclination is to fit a complete Ysus repair kit even though the components all seem ok when tested with my multimeter. I cannot see any signs of bulging on any of the caps on the Ysus board.
My question is, What could be causing the fault to occur when the boards get hot? Is there a particular component I should be looking to replace? Has anyone else had this same fault before?
The Ysus part number is LJ41-05120A.
The buffers are LJ41-05121A (UPPER) and LJ41-05122A (LOWER)
Thanks in advance for your thoughts
:-)
Comment