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Problem with Onkyo A-8500 (Integra) Amplifier

Hello,

After 19 years playing music very well, my Onkyo A-8500 (Integra line)
amplifier has problems especially when it's cold (just powered-on).
The speakers level is low and there is distortion.
Switching from the Speakers pair A to the B and back to A can lead to a
different result (better or worse output).

I think that the problem could be caused by a relay that is used to
switch the speakers pair that need to be replaced. The series
resistance of the bad contatcs that is added to the load can be the
cause of the distorsion. I see two relays in the middle of the
amplifier (they seem to be protected from dust/humidity) and a small
one on a hardly accessible little board related to speaker pair
switching (!). The last one may be not so protected from external
agents (transparent cover).


So, the questions:

- Have you the schematic / service manual of the Onkyo A-8500?
- Do you agree with me when I blame the small relay?

Best Regards and MERRY CHRISTMAS

Panino
 
A

Arfa Daily

Jan 1, 1970
0
Hello,

After 19 years playing music very well, my Onkyo A-8500 (Integra line)
amplifier has problems especially when it's cold (just powered-on).
The speakers level is low and there is distortion.
Switching from the Speakers pair A to the B and back to A can lead to a
different result (better or worse output).

I think that the problem could be caused by a relay that is used to
switch the speakers pair that need to be replaced. The series
resistance of the bad contatcs that is added to the load can be the
cause of the distorsion. I see two relays in the middle of the
amplifier (they seem to be protected from dust/humidity) and a small
one on a hardly accessible little board related to speaker pair
switching (!). The last one may be not so protected from external
agents (transparent cover).


So, the questions:

- Have you the schematic / service manual of the Onkyo A-8500?
- Do you agree with me when I blame the small relay?

Best Regards and MERRY CHRISTMAS

Panino
You may well be on the right track with suspecting a relay - but I would
suggest that it's going to be one of the big ones. The small one will just
be for signal switching, possibly to switch tape monitoring or something
like that. The big relays will be the speaker protect / select relays, and
it is quite common for them to get bad contacts giving the symptoms you
describe, on all sorts of makes and models. Very often, if you take the
amp's cover off when it is bad, then give the relay covers a sharp tap with
the butt end of a screwdriver, it will come back right. Many speaker relays
have snap-on covers, which come off easily when you slide a scalpel blade in
the crack between the cover and base, and twist. It is quite unusual for the
contacts to be burnt and pitted. Usually, they are just sooty, and all they
need is a piece of cardboard, soaked in isopropyl alcohol, drawn between
them.

Arfa
 
N

Nate Scharff

Jan 1, 1970
0
Hello,

After 19 years playing music very well, my Onkyo A-8500 (Integra line)
amplifier has problems especially when it's cold (just powered-on).
The speakers level is low and there is distortion.
Switching from the Speakers pair A to the B and back to A can lead to a
different result (better or worse output).

I think that the problem could be caused by a relay that is used to
switch the speakers pair that need to be replaced. The series
resistance of the bad contatcs that is added to the load can be the
cause of the distorsion. I see two relays in the middle of the
amplifier (they seem to be protected from dust/humidity) and a small
one on a hardly accessible little board related to speaker pair
switching (!). The last one may be not so protected from external
agents (transparent cover).


So, the questions:

- Have you the schematic / service manual of the Onkyo A-8500?
- Do you agree with me when I blame the small relay?

Best Regards and MERRY CHRISTMAS

Panino

It sounds like you are using 4 ohm speakers. Most amplifiers are only
rated for 8 ohm minimum impedence.
 
L

Leonard Caillouet

Jan 1, 1970
0
Nate Scharff said:
It sounds like you are using 4 ohm speakers. Most amplifiers are only
rated for 8 ohm minimum impedence.

Using 4 ohm speakers on an amp rated for 8 ohms would not cause low,
distorted sound unless something was damaged by drawing too much current
from the amp. Since the system worked fine for a long time, the symtom
described may be just what he suggested, a relay problem.

Leonard
 
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