Sony KDE-37XS955 Intermittently Powers Up

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JBullard
Sony KDE-37XS955 Intermittently Powers Up

I recently inherited a Sonly KDE-37XS955 plasma in one of those "if you can fix it, you can have it" deals.  As often happens, I've reached that point where I have to decide if putting any (more) money into my "free" TV is worth it.

When powered up, the TV goes through what appears to be a normal cycle:

  1. The red standby light is on steady.
  2. Press the power button
  3. Red light goes out, green light blinks twelve times then comes on steady.
  4. Wait a few seconds.
  5. ... then nothing.

The green light stays on steady, but there is no picture and the fans are not running.

Sometimes, if I wait, the fans will kick on and I'll have a picture.  At that point, cycling the power is about a 50/50 shot...maybe it will come back on, maybe not.

I opened up the case and measured various voltages (that were marked on the PCB) and several of them (the STDBY5V in particular) were not right.  For example: when I hit the power button, the 5V line would SLOWLY climb up and the fans would come on when it hit 4.something volts.  I thought "A Ha! Capacitors!" and (rather than replacing each individual cap) went and got a replacement G1 board.  Well the 5V now snaps right to 5 like it should...but I still have the same end results.

 

Does anyone have any sage advice on what to look for next?  I have a fairly strong electronics background (leftover from a previous life), so if your advice involves the words "DVM" or "scope", don't be afraid to throw it at me anyway.

Thanks in advance for any help you can give me.

evil
Have you checked in the

Have you checked in the service manual to see if there is an error code list?

JBullard
evil said: Have you checked

evil said: Have you checked in the service manual to see if there is an error code list?

I did look, and there is not a list in the service manual.  I searched the web and found a generic "Sony blink codes" list but I don't think I am even getting an error code: I think the blinking green light is just part of the normal "boot up" cycle.  If there were an error, I think the standby light would be the one blinking the code.

 

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