Problem with right channel on Sony STR-D790 Receiver

[Chris L.]

Yesterday I went to turn my receiver on and listen to an album when I
noticed I was getting a lot of distortion in my right channel speaker.
I decided to test out what was going on. I moved the right speaker to
the B output on the right channel and was experiencing the same
static/distortion. I then switched the right speaker to the left A
output and everything worked fine. To be certain, I switched the left
speaker to the right channel to find the speaker was producing the same
sound as the right speaker had earlier. So anyway, it's certainly a
problem with the right channel and not the speakers. Both the A and B
outputs are producing this very distorted static sound. I don't have
much knowledge of audio electronics, but I have worked on electronics
before and can solder, etc. But when it gets down to it, I can't
imagine where to really begin. I imagine since the left channel is
working properly (and I'm assuming both match electronically) I could
easily see where the problem is, if I knew where to begin. I'm assuming
nothing blown, but could something need to be re-soldered? The channel
is still producing sound, but it sounds quite a bit like a blown
speaker, with the static and rattling.

 

[NSM]

| Yesterday I went to turn my receiver on and listen to an album when I
....
| is still producing sound, but it sounds quite a bit like a blown
| speaker, with the static and rattling.

You need a scope and an audio oscillator, or a LOT of experience.

N

 

[Mark D. Zacharias]

Could be a driver IC, or maybe solder connections.

Mark Z.

 

[Jerry G.]

This is most likely some failed components in the audio output stage, and
the pre-driver stages. You will need a lot of experience in servicing this
type of affair, a scope, a DVM, and an audio generator to properly
troubleshoot this. You will most likely also need the service manual for
your reciever. This type of servicing can also get somewhat complex in its
nature.

An intelligent decision would be to give the set out to service center that
is able to service your reciever.

 

[Chris L.]

This is most likely some failed components in the audio output stage, and
the pre-driver stages. You will need a lot of experience in servicing this
type of affair, a scope, a DVM, and an audio generator to properly
troubleshoot this. You will most likely also need the service manual for
your reciever. This type of servicing can also get somewhat complex in its
nature.

An intelligent decision would be to give the set out to service center that
is able to service your reciever.

Good call. Thanks guys.

 

[Don McPherson]

Yesterday I went to turn my receiver on and listen to an album when I
noticed I was getting a lot of distortion in my right channel speaker.
I decided to test out what was going on. I moved the right speaker to
the B output on the right channel and was experiencing the same
static/distortion. I then switched the right speaker to the left A
output and everything worked fine. To be certain, I switched the left
speaker to the right channel to find the speaker was producing the same
sound as the right speaker had earlier. So anyway, it's certainly a
problem with the right channel and not the speakers. Both the A and B
outputs are producing this very distorted static sound. I don't have
much knowledge of audio electronics, but I have worked on electronics
before and can solder, etc. But when it gets down to it, I can't
imagine where to really begin. I imagine since the left channel is
working properly (and I'm assuming both match electronically) I could
easily see where the problem is, if I knew where to begin. I'm assuming
nothing blown, but could something need to be re-soldered? The channel
is still producing sound, but it sounds quite a bit like a blown
speaker, with the static and rattling.

Don't even attempt repairs. One mistake, and you can make matters
MUCH worse. You can look for loose solder, but more likely is a bad
driver i.c. / voltage amplifier, or a blown transistor accompanied by
a shorted transistor. The chances of it being just an open resistor
is remote.

With these type of repairs, you normally have to check all the
transistors, resistors, and diodes in the circuit before even firing
it up.

Or would you like to serve up the classic "Smoke Test"

1/2 of your push pull output circuit in that channel has an open
resistor due to a blown transistor, or the driver i.c. is involved.

Get this one to a pro or suffer the consequences. Except for a quick,
pre-fix voltage check, I don't even turn these on until after checking
all of the normal suspects.

Regards,