Onkyo SKW-591 subwoofer is dead

[tibimakai]

Re: Onkyo SKW-591 subwoofer is dead

I will solder in the final IC, and I will measure the speaker output and I will let you know. Most likely tomorrow.

[tibimakai]

Re: Onkyo SKW-591 subwoofer is dead

OK, I have soldered in Q502 and it is still not OK.
+2V in stand by and -38V, with signal.
I can't imagine why it is so hard to diagnose this amp. There are just a few components.
+/-5V and 12V, from 7805/7905/7812 are there.

[R_J]

Re: Onkyo SKW-591 subwoofer is dead

I would suspect the fet on the negative supply is being turned on, thats why I suggested checking the voltage from q501
I would leave q502 out, and check the voltages on q501, look at the pdf for the ic. It has two drive circuits, HO & LO, I suspect there is a problem with the LO side. You need to check each resistor in that output circuit and make sure they are not open, Then check q501, look at the pdf of the ic and check that the internal fets are not shorted. If all 4 are not shorted.
Check the voltage between VS & VB, then between VS & HO.
Check the voltage between COM and VCC, then between COM & LO

[tibimakai]

Re: Onkyo SKW-591 subwoofer is dead

The fet is a brand new one.

[R_J]

Re: Onkyo SKW-591 subwoofer is dead

What fet are you talking about?

[tibimakai]

Re: Onkyo SKW-591 subwoofer is dead

Q502, that I have soldered in, is a brand new one.

[tibimakai]

Re: Onkyo SKW-591 subwoofer is dead

Also, the Q501 I have solder in a few days ago, is brand new.

[andy1]

Re: Onkyo SKW-591 subwoofer is dead

If you have a scope, you can take Q502 out of the circuit and compare the output wave forms on Q501 pins 11/14. They should be opposite in phase. If there is any DC across D515 or D516, that is what you will see on the speaker terminals. You will then know which half (LO or HO) of the IC is causing the DC voltage on the speaker terminals.

[tibimakai]

Re: Onkyo SKW-591 subwoofer is dead

Thanks Andy, I have one but I'm a beginner. I will try that as well.

[tibimakai]

Re: Onkyo SKW-591 subwoofer is dead

I have looked under the microscope, and I have found two broken traces. Middle pin(GND) of the Q502, and C503.
Now it's working great.
Thank you all for your help, it is very much appreciated.
Now I have to go back to the receiver. It just clicking on and off the relay.
It used to work, but HDMI did not work and it was overheating.
After replacement of that IC it does not turn on anymore, it just clicks.

[andy1]

Re: Onkyo SKW-591 subwoofer is dead

Great to hear that the sub is working now. As for the HDMI issue, I think you are more experienced than me. I am yet to try re-flowing the 609 board I discussed on the other forum!

[tibimakai]

Re: Onkyo SKW-591 subwoofer is dead

Unfortunately, is not the DSP issue. This DSP has legs.