Sony HCD-DZ880W Receiver Dosen't Power ON

[vinceroger69]

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

pictures of how you have connected the part to the board may help maybe one of the wires you have fitted maybe to the wrong pcb point?

[ortiko]

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

Actually i didn't use wires to connect the IC.
I cutted old IC pins and then bend them to solder them with new one (Greek patent... ).
See picture below please

Parts and the heatsink was removed to make the soldering accessible and after that of course was back in place before ps was powered on

[vinceroger69]

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

in post 20 i see the part you have used has a diffrent top part of number does this make a diffrence? or is it just a package type marking ie legs bent diffrent maybe budm will comfirm

[Agent24]

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

in post 20 i see the part you have used has a diffrent top part of number does this make a diffrence? or is it just a package type marking ie legs bent diffrent maybe budm will comfirm

That or just a datecode.

The PDF linked was not a real datasheet so it's hard to say. But the photo in there shows the lead forming the same as the replacement that was purchased, maybe the original one was a custom order.

[ortiko]

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

The voltage measurements taken before the IC was replaced and "spark" occurred was exact as with new IC.

After the "spark" and with not replaced IC there was no voltage at all

The above is a clue i think that the IC is ok

[budm]

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

That is why it is really confusing as to why it is able to run at about 1/2 of the Voltage as design (we alredy verify that the 20V regulator is OK using the external power supply.

[ortiko]

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

What about PC903 ?
Maybe it causes the problem ?

[budm]

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

PC903 Opto is for switching on and off the 30V power supply of the amplifiers.
At this point we are not getting enough voltage to run IC901.
You also still have another problem in the main board which is not sending the signal to turn on PC903, we had to use resistor for the force on.

[ortiko]

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

PC903 Opto is for switching on and off the 30V power supply of the amplifiers.
At this point we are not getting enough voltage to run IC901.
You also still have another problem in the main board which is not sending the signal to turn on PC903, we had to use resistor for the force on.

Havent connect the resistor. Mesurments was taken without anything connected to board exept mains plug

[budm]

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

"Havent connect the resistor. Mesurments was taken without anything connected to board exept mains plug" But you did do that earlier as I suggested to find out if the 30V power supply is working or not.
You can short the E to C of Q901 also if you do not want to use the resistor to turn on the Opto to see if tjhe 30V power supply will work with only 11V Vcc.

[ortiko]

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

I used a 120 Ohms resitor to pins 2 and 4 of CN906 and no voltage at all at CN 904.
Removed the resistor and no voltage either.

[budm]

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

I used a 120 Ohms resitor to pins 2 and 4 of CN906 and no voltage at all at CN 904.
Removed the resistor and no voltage either.

That is correct because the IC901 circuit is not functioning when the resistor for force on is applied, and for sure it will not be on if no resistor is connected.'
We use the resistor to simulate EN signal so we do not have the have the main board connected. I believe we need to get the 20V for the IC 901 to work.

[ortiko]

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

Any idea what do next?

[budm]

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

Not sure yet.

[ortiko]

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

I am very disappointed with this PS and don't know what more to do...
Yesterday i removed IC 901 just to see if anything with voltages changes.
With IC901 removed and installed voltage whas the same

In schematic voltage is 152 Volts and i read 320V with my voltmeter on pin 3
(this is like pin 7 at IC921)
The above makes me think that maye the problem is at the very basics of PS ?

[budm]

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

The SCH has many errors in the Voltage indicator, @230VAC input to the bridge rectifier, the filter cap will be charged up to the peak of the sine wave, so the VDC on the cap will be = 230V x 1.414 = 3.25 - 2Vf of the rectifier.
At 120VAC input, the Voltage on the cap will be 120 x 1.414 = 169VDC.
I am still trying to find out how to get the 28VDC feeding the 20V linear regulator circuit, may be there are missing info I am not seeing in the SCH.
I am hoping some one else may have the same board as yours to take some Voltage measurement for us.

[rosbif]

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

Hi guys,

I am still trying to find out how to get the 28VDC feeding the 20V linear regulator circuit, may be there are missing info I am not seeing in the SCH.

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

[rosbif]

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 was pretty warm.
I measured the resistance from VCC to GND of IC921: only about 7 ohms so obviously something was very wrong in the vicinity.
On another forum I read that capacitors in Sony products rarely fail so I thought "shit, IC921 must be dead".
(Particularly as, while searching for IC921's data sheet I saw that someone was trying to sell them on Amazon at £71.00 + £12.00 shipping )
Otherwise C912 seemed the most likely to fail so I unsoldered it and found with relief that it was indeed short circuit.
I replaced it and my DAV-DZ280 came back to life

Thank you all for your invaluable help.
I hope that this account of my experience helps others in turn.

[budm]

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

So the substituted board from DAV-DZ280 has shorted out C912? or the original board has shorted out C912?
If the original board has shorted C912, the that will not make sense because on post 44:
https://www.badcaps.net/forum/showpo...0&postcount=44

We checked the voltage on C912 and it was showing 9~12VDC.
But the bottom line is that you are using the board from DAV-DZ280 to fix the HCD-DZ880W, right?
Thanks for the follow-up.

[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.