Sony HCD-DZ880W Receiver Dosen't Power ON

[tw2005]

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

Hi, I was looking at this quickly and this cct looks similar to another Sony receiver which would not powerup. Equivalent to yours at Pin 4 on IC921 we had low voltage, we injected correct volatge using ext PSU and it fired up. From memory I think equivalent to Q922 was showing short or incorrect voltages but i was a shorted zener that was the fault.

looking at this I'm thinking DZ901 as it sits across Q922

Don't know if this info will prove helpful for you or not. I'm still trying to see if I have the manual for whatever model it was i had.

It was a HCD-S550, I've marked the part that had failed on that. Not quite as similar as I thought but you never know.

[rosbif]

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

But the bottom line is that you are using the board from DAV-DZ280 to fix the HCD-DZ880W, right?

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.

[ortiko]

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

I am back with some updates to report

Yesterday after changing C910 and installing the pcb on chassis by connecting pin 4 with pin2 of CN906 all VOLTAGES are present!!!
At CN904 i have the desired 31,5 Volts but problem remainss...
The front panel doesn't go on although the above readings

I have started searching the panel pcb and found IC5000 that has only VIN 4V and no Vout 3,3V. This IC is not on schematic i have provided but is identical to IC102 on this Schematic

Maybe someone has the Schematic for my HCD-DZ880W ?

Below are posted pics of IC102 that is the same part like IC5000 on my pcb and a picture of my pcb for reference

[Agent24]

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

Can you find a part number for that IC? What does it say on it?

Maybe it has some enable line and it's being turned off?

[ortiko]

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

It says R33 on it

[Agent24]

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

Did you check Pin 1 for 3.6v? If Pin 1 is low then the regulator will be in shutdown mode.

[johnn635]

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

Many thanks to the users of this forum who provided the links to the Schematics I needed to fix a Sony DZ260 that would not turn on reliably following a power outage.https://www.badcaps.net/forum/images/smilies/rockon.gif

It transpired that C926, which gets the startup voltage from IC921 had a high ESR, although it still measured about 20uf on my cheap meter. Interestingly, using a 47uf - which is a value in the range suggested by the MR4000 application note would not allow startup.

Locating this capacitor between the heat sink and the transformer probably accounts for its premature failure. It was also a 85deg C rated unit, so replaced with a 105 deg c device.

If someone has some suggestions to resurrect an expensive Tek 4 channel DSO which I believe is also cap related, then please reply or create a thread ( I can't yet)
John

[mschmitz]

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

With all due respect to everyone involved, nothing said in this post enabled me to find the problem on my 09DAV-Power-MR-MP-12 power board. I followed all suggestions here, but the 32V outputs will not increase beyond 7.8V for the amps, forced on by resistor or not! So far I have 3 units from customers at my shop and all have the exact same problem: Protect Press Power. and no 32V! As far as I am concerned is that Sony built in obsolescence due to failure and only their techs know where to look. Transistors, switching IC,s and diodes are fine - still no power. I hate that everybody uses those garbage switching junk power supplies today - they always fail and damage other components and they are a bitch to fix. I miss my good old brick wall transformer supplies. They never ever failed even when they received a surge, plus they were straight forward. I just went back to my self restored 1960 tube audio system connected to my laptop with blue ray drive and memory card reader. If those fail, the card reader is 10USD and the blue ray is 30USD to replace, versus 300USD or more for this Sony garbage with SMPS!

[Agent24]

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

You did not mention checking any capacitors. The thread mentions at least C912 and C910 having been faulty for some people.

[farux]

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

Hello, maybe actual in 2021)
I had the same problem with low voltage on Q922, C926 and C912 (about 10-11v).
I`ve checked all capasitors and other elements that mentoned above, but they were ok.
There were supply circuit problem in Q922: SMD R992 was damaged, its replacemet made unit work )

[michel74]

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 waiting for a new one
While waiting ... does someone have an idea what I could verify ? C912, C921 and C926 are ok; D921 and 946 too
In diode mode, when I measure DZ901, I have 0.7V but when I reverse the probes ... I get 0.6V. But I believe it's normal when we look at the way it is cabled (between C-E of Q922)
If anyone could help, thanks in advance

[nomoresonys]

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

You could lift a leg and test it out of circuit, if it reads the same it's bad.

[michel74]

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 ...

[duke267]

Hi I bought one of these home theaters for the speakes but when the reciever powered on upon plugging it in I decided to give it a go at repairing it. My problem lies with no output at CN904, I've been probing around and noticed no voltage at pin 4 of IC901, but measured correct voltage at the base and emitter of Q901, could it be that just this bjt went bad? Thanks for the help in advance