Any Sony "G" power board gurus out there?

I have a "G" 1-659-752-21 board Q601 and Q602 blown, and replaced, with D648
(150 v protect zener)

Board works, but has almost NO regulation for +130v out...100VAC in outputs
+145V B+
Oddly, the LOAD regulation is good, pix size does not change with
brightness...

Any 1 part that screams "I'M BAD"?

Aaron H.

 

I'm not a TV guy, but from what you say, it's actually regulating perfectly.

The REFERENCE is bad.

Comparing to stuff I actually know, on a vcr smps, if the 5-volt line is
noisy (bad cap) the other voltages will run high.


Mark Z.

 

Do an ESR test on all the caps in the supply and horiz scan circuits.

--

Greetings,

Jerry Greenberg GLG Technologies GLG
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I have a "G" 1-659-752-21 board Q601 and Q602 blown, and replaced, with D648
(150 v protect zener)

Board works, but has almost NO regulation for +130v out...100VAC in outputs
+145V B+
Oddly, the LOAD regulation is good, pix size does not change with
brightness...

Any 1 part that screams "I'M BAD"?

Aaron H.

 

I had one that one of the small transformers on the board in the area of the
2SC4834s was bad causing no regulation. The only way I found it was after
checking virtually every part it was about all that was left, so I changed it.
A very tough problem to diagnose, an ohmeter ain't going to find this problem.
Ron