A short update ...

After having burn some other fuse resistors and other power IC module, I finally managed to "build" (assemble ?) this "dim bulb tester" as suggested by [USER="6996"]momaka[/USER].. and it definitely helped !
After replacing the fuse and the IC (I think I burned 6 of then ...), when the PSU was powered on, I had no specific issue; but when plugging the main board to it, the bulb was ... blinking. This was a good sign to say that a cap was going mad somewhere;
When I was testing the DC value at the main cap, I was having the...

Re: How does this work ?

Thanks PeteS,
I got these ones, :-)
My question was more about how we get this permanent VCC? When the A/C plug is .. plugged, we should have a permanent VCC “somewhere”, no ?

Hi everyone,

Yes ! How does this switching PS works ? :-)
I understand (not in deep, of course) the switching PS principle; typically, I'd expect to get a VCC just to "feed up" the STR or the Switching regulator, but I cannot figure how this VCC is "created" (on a TV switching PSU, I often see some cascaded resistors, but here, I believe that one of the transformer input should make the permanent VCC, but I cannot figure where )
Thanks for your help. I already wrote some explanation of what I was having and did some measurements here [URL="...

Re: Sony HCD DZ280 PSU

Thanks momaka, so I went around looking for some bulbs and ... hard to find. I will to the test tonight
...
Most of the tests you ask to performed above were already done, but I re-checked the component.
C912 was showing 40uF instead of 47uF, but I replaced it for the other tests, everything is ok.

I wanted to make some continuity check around IC921, but because of the very low value of R922 (0.18Ohm) the tester always bips between pins 3 and 5; and between pins 7(Vin) and 9 (Drain), I have a very low resistance (0.5 ohms) <=...

Hello everyone,

I'm having an issue with PSU;
When I had it in hands the resistor fuse FR929 (1Ohm) was dead. IC921 (MR4020 - Switching reg.) was dead too.
I replaced both; when plugging the AC cord, nothing goes wrong. When switching On the equipment, the display shows something for few sec, and FR 929 blows again. Not sure if IC921 was still ok, so I replaced both again (...)

Now, when I plug the AC cord, ... FR929 blows directly.

When I measure resistance between pin 3 and 7 (Gnd and Vin) of IC921 I have less than 1 Ohm ... So, I changed...

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

Good idea, but I will do it with the transistor, as the diode is a 602 SMD size ...

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

Hello everyone,
So, almost 10 years after the first post on this thread but ... still this DAV Z280 is used by someone around the world :-)
Someone brought me this PSU for repair; at first, the 1 Ohm res fuse was cut. IC921 was shorten too.
When I replaced both, I have all the powers on CN 906; when switching ON the equipment, the front panel switches ON but ... only for few sec; after that, FR929 blows again; IC921 was ok, but I wanted to test it outside the board and ... obviously I damages one of the pin; so I'm...

Re: New Members - please post your introductions here

Hello everyone from switzerland !!!
This place is full of information i canot find anywhere else !
I've been reding a lot without registering but now it's time :-)
Need to learn stuff on troubleshooting devices and as far as I know :there's no age to start !
Thx