Pioneer PDP 504 PG. no picture and 3 blinkling Red LEDs

[JCTech0101]

Firstly, many thanks to Tom66 and the many outstanding contributions which enabled my first diagnosis.

Problem:
When power is turned on, the TV picture is pink (see pic) and powers down after 3-5 seconds, then the Red front panel LED blinks 3 times.

Conclusion so far:
Everything points to this being the 50 scan B, based on the 3 LED blinks, defective looking IC on the board (I missed this in first inspection) and the service manual.

Main question: if it is Scan B, then why do I still get power down with the board disconnected, especially when the scan B board is disconnected? Could there be another problem? Has anyone else had the same error.

Picture of screen & IC attached.

Checks conducted:

1. Disconnected power to drive & scan assemblies, one by one

Disconnected power to Y drive: same power down and 3 red flashes on front panel

Disconnected power to X drive: same power down and 3 red flashes on front panel

Disconnected power to lower Scan Y drive: power down and 3 red flashes on front panel

Disconnected power to upper Scan Y drive: power down and 4 red flashes on front panel

2. Visual inspection:
No obvious blown caps on any of the boards. IC in upper scan Y looks defective (pic attached).


3. Voltage checks from the check points on the power supply:
Vsus : 223v
16.5v output: 16.45v
6.5v output: 6.64v (started at 6.8v then reduced to 6.45v before the power down)
VADR: 16.5v

Note: There is no LED illuminated on the power supply, only a continuous red LED on the Digital Video Assembly board which lights after power down. When power is turned on, 2 other LEDs light up on this board first, then turn off when Red LED turns on.

[JCTech0101]

Re: Pioneer PDP 504 PG. no picture and 3 blinkling Red LEDs

Update to the above - as future info to others:
The y-scan boards are bonded to the screen, so the only way I see for repairing a defective IC is to replace the IC, leaving the board in place. Not sure how easy or expensive that is.

[Truncatedhose]

Re: Pioneer PDP 504 PG. no picture and 3 blinkling Red LEDs

Update to the above - as future info to others:
The y-scan boards are bonded to the screen, so the only way I see for repairing a defective IC is to replace the IC, leaving the board in place. Not sure how easy or expensive that is.

I have two of these models right now and have been sitting on them for a while, debating whether to attempt the repair or not. One has at least two bad IC's and I ordered them, but they've just been sitting there, waiting for me to make up my mind and chance it or not. I'm worried that there could be something else wrong with the set and that of course changing the IC's is kind of a pain if you haven't done it and gotten good at it. The other model only has one visibly bad IC, but again, what if more are bad or what if these also have a bad Y-SUS?