Onkyo TX-82 stereo receiver fault. Suggest possible solutio

On Aug 16, 9:20 pm, "William Sommerwerck" <grizzledgee...@comcast.net>
wrote:

Checking for DC in the speaker terminals. Bank A left reads 8.3mV.
Bank A right reads 5.9mV. Bank B left reads 8.4mV. Bank B right reads
6.1mV.

Have you sat there watching the meter to see if the offset jumps up when the
relay opens? (I'm sure you have better things to do with your time!) Some
DMMs have a trending feature that keeps track of the highest voltage.

Arfa's suggestions are a good place to start.

Right now, I want to figure out what is going on and I have the time
at this moment to do that.

I measured the power and, on the left channel, the offset fluctuates
between a peak of 11.3 mV and 8.3 mV. Is this significant?

Unfortunately, I missed the meter reading right at the moment the
protection relay tripped.

 

... I've just been looking at the protection circuit for a current
model Onkyo receiver (TX-8211) that appears to monitor the load
current in the 0.22 ohm emitter resistors of the output transistor
pair. If either resistor were to intermittently go open, then this
would trigger the protection. I have seen this problem in a car amp.
In that instance, one of the pins of a ceramic emitter resistor
fractured due to vibration.

- Franc Zabkar

Interesting thought.

According to the schematics and parts list, if I'm reading it right,
Q508 and Q509 (transistor pairs for the left) work with R512 and R513,
which are a matched pair of metal plate resistors rated at 2W and .47
ohms. The right channel transistor pair are Q608 and Q609 and their
resistors are R612 and R613. The resistors on the right channel are
identical with those that are on the left, of course.

So, how would I go about testing the resistors? Would I lightly tap
on each one with a plastic probe and see whether or not the protection
relay trips?

 

On Aug 18, 12:09 am, Franc Zabkar <fzab...@iinternode.on.net> wrote:

On Sun, 17 Aug 2008 20:58:49 -0700 (PDT), laseranddvd...@aol.com put
finger to keyboard and composed:

Would it be okay for me to e-mail you a PDF of the service manual?

Yes. I'll upload it to eserviceinfo for the group, if that's OK,
otherwise I'll put it on my web site.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

Go ahead with whatever you'd like to do with the file.