Hi all,
I am trying to fix this receiver, I replaced the hybrid STK080G
power amp for the right channel, after having checked the voltages on
the pins. Now this power amp goes red hot when powered on.
Any ideas what/how to check ?

Thanks

Francois

wrote in message
...
Hi all,
I am trying to fix this receiver, I replaced the hybrid STK080G
power amp for the right channel, after having checked the voltages on
the pins. Now this power amp goes red hot when powered on.
Any ideas what/how to check ?

The driver ... the circuit that feeds the hybrid.

Thanks Charles,
I checked the voltages(DC) on all pins on both hybrid power amps and
they are the same. I swapped the input to the hybrid power amps (left
and right channels) and I still have the same power amp getting very
hot. Not sure what to check next.






On Sun, 5 Mar 2006 20:07:34 -0500, "Charles Schuler"
wrote:


wrote in message
.. .
Hi all,
I am trying to fix this receiver, I replaced the hybrid STK080G
power amp for the right channel, after having checked the voltages on
the pins. Now this power amp goes red hot when powered on.
Any ideas what/how to check ?

The driver ... the circuit that feeds the hybrid.

On Mon, 06 Mar 2006 13:12:54 -0500, wrote:

Thanks Charles,
I checked the voltages(DC) on all pins on both hybrid power amps and
they are the same. I swapped the input to the hybrid power amps (left
and right channels) and I still have the same power amp getting very
hot. Not sure what to check next.


Without speakers connected,of course?

Speaker connected (switch on or off for them), right channel power amp
still very hot. The sound is good on both speakers but I cant leave it
on for long, I am afraid to fry the power amp ($20.00)


On Mon, 06 Mar 2006 19:37:03 +0100, Damir wrote:

On Mon, 06 Mar 2006 13:12:54 -0500, wrote:

Thanks Charles,
I checked the voltages(DC) on all pins on both hybrid power amps and
they are the same. I swapped the input to the hybrid power amps (left
and right channels) and I still have the same power amp getting very
hot. Not sure what to check next.


Without speakers connected,of course?

wrote in message
...
Speaker connected (switch on or off for them), right channel power amp
still very hot. The sound is good on both speakers but I cant leave it
on for long, I am afraid to fry the power amp ($20.00)


On Mon, 06 Mar 2006 19:37:03 +0100, Damir wrote:

On Mon, 06 Mar 2006 13:12:54 -0500, wrote:

Thanks Charles,
I checked the voltages(DC) on all pins on both hybrid power amps and
they are the same. I swapped the input to the hybrid power amps (left
and right channels) and I still have the same power amp getting very
hot. Not sure what to check next.




If the sound is good, but the hybrid is frying, then I would suggest that it
is hooting, maybe as high as RF. You need to get a 'scope on the output to
check for this. There may be a Zobel network ( R & C in series ) on the
output that was damaged by the previously faulty hybrid. Alternatively,
there may be a defective decoupling cap on one of the bypass pins of the
hybrid, or an open or high ESR supply decoupling cap, and this is allowing
it to hoot, which may be what caused the demise of the original hybrid, and
would ultimately do the same to the replacement, if left.

Arfa