I had the good fortune of garbage-picking a Marantz SR685 surround sound
receiver. However, naturally it doesn't work quite right (or else it
wouldn't have been in the garbage). I can hear audio intermittently. From
what little I know about these things, it seems the power amp is working
but the preamp is cutting in and out. Sometimes it seems to "warm up" for a
short time and the full sound comes out. The rest of the time it is
inaudible unless I turn the volume up all the way, and then I hear just a
little bit. Any suggestions on what is wrong or what I can do?

Thanks for your help!!!
Alex

"Alex" wrote in message
. 136...
I had the good fortune of garbage-picking a Marantz SR685 surround sound
receiver. However, naturally it doesn't work quite right (or else it
wouldn't have been in the garbage). I can hear audio intermittently. From
what little I know about these things, it seems the power amp is working
but the preamp is cutting in and out. Sometimes it seems to "warm up" for
a
short time and the full sound comes out. The rest of the time it is
inaudible unless I turn the volume up all the way, and then I hear just a
little bit. Any suggestions on what is wrong or what I can do?

Thanks for your help!!!
Alex

I've seen several Marantz surround models that had various bad solder
connections. Some involved the vertical pc boards where they connect at the
top, or if there is no connect board, sometimes the DSP board IC's need to
be resoldered. This would be a job for a professional - the IC leads,
hundreds of them, are much too small for the average person to cope with.

Mark Z.

"Alex" wrote in message
. 136...
I had the good fortune of garbage-picking a Marantz SR685 surround sound
receiver. However, naturally it doesn't work quite right (or else it
wouldn't have been in the garbage). I can hear audio intermittently. From
what little I know about these things, it seems the power amp is working
but the preamp is cutting in and out. Sometimes it seems to "warm up" for
a
short time and the full sound comes out. The rest of the time it is
inaudible unless I turn the volume up all the way, and then I hear just a
little bit. Any suggestions on what is wrong or what I can do?

It would be odd for two (or more) channels to go out at the same time as
I'll wager most of the circuitry for the amp is discrete, i.e. you probably
have one transformer feeding two power supplies feeding two amps. However,
it's possible that either the amp or preamp makes use of a dual amp output
chip. A schematic would really help you (or your repair tech) to quickly
ascertain which component(s) are common to both output channels.

On the back of the unit are there "pre-out" and "main in" jacks that have
been jumpered together? Some models have this, allowing you to separate the
preamp from the amp and thus narrow down the problem.

If you have no schematic and limited technical ability, your best bet is
probably to take it to a pro who has both the expertise and the test
equipment to diagnose your problem.

One last thought: a previous poster noted bad solder joints as a recurring
issue with some Marantz models. Try wiggling the peripheral boards when the
unit is powered up and has an input signal and see if this produces any
changes. If it does, solder joints may be the culprit.

Good luck.

Dave

You might also try hooking your source to different inputs (tape, aux, cd,
etc.) on the back of the receiver... a dirty input selector switch or a
switch gone bad may produce the symptoms you describe.

Dave

"Dave" wrote in message
news:nFkhf.129579$y_1.75424@edtnps89...

"Alex" wrote in message
. 136...
I had the good fortune of garbage-picking a Marantz SR685 surround sound
receiver. However, naturally it doesn't work quite right (or else it
wouldn't have been in the garbage). I can hear audio intermittently. From
what little I know about these things, it seems the power amp is working
but the preamp is cutting in and out. Sometimes it seems to "warm up" for
a
short time and the full sound comes out. The rest of the time it is
inaudible unless I turn the volume up all the way, and then I hear just a
little bit. Any suggestions on what is wrong or what I can do?

It would be odd for two (or more) channels to go out at the same time as
I'll wager most of the circuitry for the amp is discrete, i.e. you
probably
have one transformer feeding two power supplies feeding two amps.
However,
it's possible that either the amp or preamp makes use of a dual amp output
chip. A schematic would really help you (or your repair tech) to quickly
ascertain which component(s) are common to both output channels.

On the back of the unit are there "pre-out" and "main in" jacks that have
been jumpered together? Some models have this, allowing you to separate
the
preamp from the amp and thus narrow down the problem.

If you have no schematic and limited technical ability, your best bet is
probably to take it to a pro who has both the expertise and the test
equipment to diagnose your problem.

One last thought: a previous poster noted bad solder joints as a
recurring
issue with some Marantz models. Try wiggling the peripheral boards when
the
unit is powered up and has an input signal and see if this produces any
changes. If it does, solder joints may be the culprit.

Good luck.

Dave



I was able to induce or temporarily fix the problem with a hair dryer
directed at the suspect boards. The DSP generally is the one with the
digital inputs, or where the digital inputs loop over to.

Mark Z.