Hi all,
I am trying to fix this Plasma TV that doesn't turn on The 5V standby supply delivers fluctuating voltage form 1.2 to 1.5 volt. I replaced the driver IC IEC2A280 without success, checked all caps, nothing looks bad on either HOT or COLD side.
The standby PSU section starts and delivers output power but stops quickly, not allowing enough time to raise the output voltage. It looks that the feedback provided by an opto isolator do not deliver control to the driver IC because the output voltage is not high enough. The VCC voltage of the driver IC is not correctly re-enrgized by the PSU transformer because pulses are too short so the VCC derived from the high voltage raise enough to soft start the PSU but drops when soft start performs due to power needed by the driver IC, droping below 8.5 volts which stops the PSU. And so on.
I found the schematic of the PSU board BN96-01464A at elektrotanya but it is different thant the board I have which is much more complicated on the Stby section (at least).
Does anybody has a correct schematic available or an idea, this failure seems to be common according to other forums but never found a correct solution.
Thanks for any help or advice. Regards. Jean
I am trying to fix this Plasma TV that doesn't turn on The 5V standby supply delivers fluctuating voltage form 1.2 to 1.5 volt. I replaced the driver IC IEC2A280 without success, checked all caps, nothing looks bad on either HOT or COLD side.
The standby PSU section starts and delivers output power but stops quickly, not allowing enough time to raise the output voltage. It looks that the feedback provided by an opto isolator do not deliver control to the driver IC because the output voltage is not high enough. The VCC voltage of the driver IC is not correctly re-enrgized by the PSU transformer because pulses are too short so the VCC derived from the high voltage raise enough to soft start the PSU but drops when soft start performs due to power needed by the driver IC, droping below 8.5 volts which stops the PSU. And so on.
I found the schematic of the PSU board BN96-01464A at elektrotanya but it is different thant the board I have which is much more complicated on the Stby section (at least).
Does anybody has a correct schematic available or an idea, this failure seems to be common according to other forums but never found a correct solution.
Thanks for any help or advice. Regards. Jean