I have a Harman Kardon PM 955 and the right channel is working
intermittently. It works ok when first turned on, then after awhile it
starts to cut out and then quits working all together. My question is this,
would this be hard to diagnose/repair for a novice? I consider myself
mechanically inclined and I'm willing to attempt the repair if it's not
overly complex. Secondly, if this requires more expertise will it require
genuine HK parts that may not be available (the unit is approximately 20
years old) or could this be repaired with generic electronic components?



Thanks in advance,



Mark

Mark Savoy wrote:

I have a Harman Kardon PM 955 and the right channel is working
intermittently. It works ok when first turned on, then after awhile it
starts to cut out and then quits working all together. My question is this,
would this be hard to diagnose/repair for a novice? I consider myself
mechanically inclined and I'm willing to attempt the repair if it's not
overly complex.

Open amp, prod around gently with an insulated tool to find the spot
most senitive to prodding. You should be able to narrow it down to a
single wire or single joint. Resolder the bad solder joint, which is
what it will be in 99% of cases.

Beware of the live bits in there, dont do if youre not capable of
working on live things safely.


Secondly, if this requires more expertise will it require
genuine HK parts that may not be available (the unit is approximately 20
years old) or could this be repaired with generic electronic components?

99.5% likely all generic parts.


NT

wrote:
Mark Savoy wrote:

I have a Harman Kardon PM 955 and the right channel is working
intermittently. It works ok when first turned on, then after awhile
it starts to cut out and then quits working all together. My
question is this, would this be hard to diagnose/repair for a
novice? I consider myself mechanically inclined and I'm willing to
attempt the repair if it's not overly complex.

Open amp, prod around gently with an insulated tool to find the spot
most senitive to prodding. You should be able to narrow it down to a
single wire or single joint. Resolder the bad solder joint, which is
what it will be in 99% of cases.

Beware of the live bits in there, dont do if youre not capable of
working on live things safely.


Secondly, if this requires more expertise will it require
genuine HK parts that may not be available (the unit is
approximately 20 years old) or could this be repaired with generic
electronic components?

99.5% likely all generic parts.


NT

HK's are fairly notorious for the tape monitor and filter switches cutting
out. Try manipulating (slightly pushing or tapping) these switches when your
problem occurs. I think you'll find your problem is in these switches.

Mark Z.

If your receiver has a speaker protection relay (that clicks on after a
few seconds of powering up) the contacts might be dirty (oxidized).

Mark D. Zacharias wrote:
wrote:
Mark Savoy wrote:

I have a Harman Kardon PM 955 and the right channel is working
intermittently. It works ok when first turned on, then after awhile
it starts to cut out and then quits working all together. My
question is this, would this be hard to diagnose/repair for a
novice? I consider myself mechanically inclined and I'm willing to
attempt the repair if it's not overly complex.

Open amp, prod around gently with an insulated tool to find the spot
most senitive to prodding. You should be able to narrow it down to a
single wire or single joint. Resolder the bad solder joint, which is
what it will be in 99% of cases.

Beware of the live bits in there, dont do if youre not capable of
working on live things safely.


Secondly, if this requires more expertise will it require
genuine HK parts that may not be available (the unit is
approximately 20 years old) or could this be repaired with generic
electronic components?

99.5% likely all generic parts.


NT

HK's are fairly notorious for the tape monitor and filter switches cutting
out. Try manipulating (slightly pushing or tapping) these switches when your
problem occurs. I think you'll find your problem is in these switches.

Mark Z.

wrote:
If your receiver has a speaker protection relay (that clicks on after
a few seconds of powering up) the contacts might be dirty (oxidized).

Mark D. Zacharias wrote:
wrote:
Mark Savoy wrote:

I have a Harman Kardon PM 955 and the right channel is working
intermittently. It works ok when first turned on, then after
awhile it starts to cut out and then quits working all together.
My question is this, would this be hard to diagnose/repair for a
novice? I consider myself mechanically inclined and I'm willing to
attempt the repair if it's not overly complex.

Open amp, prod around gently with an insulated tool to find the spot
most senitive to prodding. You should be able to narrow it down to a
single wire or single joint. Resolder the bad solder joint, which is
what it will be in 99% of cases.

Beware of the live bits in there, dont do if youre not capable of
working on live things safely.


Secondly, if this requires more expertise will it require
genuine HK parts that may not be available (the unit is
approximately 20 years old) or could this be repaired with generic
electronic components?

99.5% likely all generic parts.


NT

HK's are fairly notorious for the tape monitor and filter switches
cutting out. Try manipulating (slightly pushing or tapping) these
switches when your problem occurs. I think you'll find your problem
is in these switches.

Mark Z.

HK's rarely use relays - not sure why, except for cost. They did often use
little black circuit breakers at the amp outputs, but they rarely failed
because they were always ON except when triggered.

Mark Z.