LG Plasma TV;50PC51-ZB;Chassis:LP78A(B) PP78A (B);no picture an OSD;Sound ok

[Sven76225]

Hello,

I am a television engineer and need help.

 

A 50PC51-ZB TV television stands on my desk.

PDP Model : PDP50X40D46


Mistake:

- No picture and no OSD insertions
- Sound available

A visual examination was carried out.

The front LED shines after him switch on permanently green. The screen is getting light for half a second. It appear, on top on the right in the corner to letter. However, these are very difficult to recognise.Complete screen black.

The operating voltages VA, VS, 5 V, 3.3 V exist. The fan works. On the 50X4A_CTAL_256 board all SMD DIODES SMD shine except D1 and D2. These diodes are nearby to IC 101.

I measure on the power board

Plug P800 ( See appendix ) Picture 1

The voltage 3.4V_ON is higher. The voltage value is 4,48 V. Where the voltage is generated. Have a bad circuit diagramm. From it this is not award.  

On the signal processor Board (board name : 50X4A_CTAL_256CH Patr No : EAX37080201    REV : F) is an oscillator (see figure appendix). On the signal processor Board is an oscillator (see figure appendix) I measure To the resistor (R51) 3.3 volts!

I measure to the voltage converter, unfortunately only 5 V and 3.3 V. Where I measure 1,8 V and 2,5V? I need a better circuit diagramm. Please !

Thanks for your help.I wish a nice weekend.

Greeting Sven