Re: Sony HCD-DZ880W Receiver Dosen't Power ON



No, wrong ;-)

Sorry for the confusion but I am not the original poster.

I only have a DAV-DZ280 but it has a virtually identical PSU.
I am just reporting how I fixed my own PSU with a similar problem, hoping it may be of help to someone else....

Re: Sony HCD-DZ880W Receiver Dosen't Power ON

Thanks to your help I fixed mine: C912 had failed (short circuit).

More details :-
I have a DAV-DZ280 with a 09DAV-POWER-MR-MP-12 (instead of -13) power supply board which is virtually identical.
The symptoms were similar: it didn't power on and mine had 0 V on all outputs.
I checked the resistors you suggested above and all were OK.
However there was only about 200 mV on the emitter of Q922 and even less on VCC of IC921.
The 320 V rail was OK and I noticed that the heatsink of IC921...

Re: Sony HCD-DZ880W Receiver Dosen't Power ON

Hi guys,



I found the answer to this fron the description of Vin on IC921's data sheet: "Supplies current to Vcc only at startup, and automatically shuts off after startup.".

So 28 V and hence 20 V only appear on the linear regulator once IC921 has started switching; prior to this IC921 supplies its own VCC.

Cheers,
Chris...