Hi,

I recently came into possession of a 1970 Pioneer SX-9000 receiver.
While trying it out I found that when changing the volume a loud
crackling sound was coming out of the speakers. I researched the
issue and found it was most likely due to dirty contacts, I tried
some tuner spray but it didn't do anything. I also noticed a hissing
sound coming out of the speakers when no music was being played and a
"clunk" noise when turning the unit off. At this point, I contacted a
local electronics repair shop and took it in for an estimate. They
gave me an estimate to clean the contacts and replace a few capacitors
that were bad. Well, I picked up the unit yesterday and 95% of
cracking is gone and no more clunking happens when powering the unit
off. However, the hiss remains. In the google archives, I found the
following:

http://groups.google.com/groups?q=pi... le.com&rnum=1


The problems outlined in this post are mostly what is happening to
mine. The one thing I can add is the hissing gets much worse in one
channel as the receiver warms up. Within 15 minutes, the hiss becomes
noticeable and starts to degrade the sound of the music coming out of
that channel.

Any suggestions on what I should do to fix this? The above repairs
already cost me $65 and I don't want to put much more money in to
this. My electronics skills are minimal (I can solder a bit), so if I
knew exactly where the problem was I could try to fix it myself.
Also, do I have a beef with the repair shop?

Any advice and suggestions would be helpful.

Thanks,

Greg

Most shops would at least credit the prior repair cost, and charge only a
modest additional for resolving the problem. Might even charge only the
additional parts cost. May have a bad transistor or another coupling cap
could cause this. The link you gave to an SX-1010 would not be directly
applicable. Totally different model.
If the problem is appearing consistently, it shouldn't be too difficult for
an experienced tech armed with a schematic. Without a schem it could get
dicey.

Mark Z.


"Greg" wrote in message
...
Hi,

I recently came into possession of a 1970 Pioneer SX-9000 receiver.
While trying it out I found that when changing the volume a loud
crackling sound was coming out of the speakers. I researched the
issue and found it was most likely due to dirty contacts, I tried
some tuner spray but it didn't do anything. I also noticed a hissing
sound coming out of the speakers when no music was being played and a
"clunk" noise when turning the unit off. At this point, I contacted a
local electronics repair shop and took it in for an estimate. They
gave me an estimate to clean the contacts and replace a few capacitors
that were bad. Well, I picked up the unit yesterday and 95% of
cracking is gone and no more clunking happens when powering the unit
off. However, the hiss remains. In the google archives, I found the
following:


http://groups.google.com/groups?q=pi... le.com&rnum=1


The problems outlined in this post are mostly what is happening to
mine. The one thing I can add is the hissing gets much worse in one
channel as the receiver warms up. Within 15 minutes, the hiss becomes
noticeable and starts to degrade the sound of the music coming out of
that channel.

Any suggestions on what I should do to fix this? The above repairs
already cost me $65 and I don't want to put much more money in to
this. My electronics skills are minimal (I can solder a bit), so if I
knew exactly where the problem was I could try to fix it myself.
Also, do I have a beef with the repair shop?

Any advice and suggestions would be helpful.

Thanks,

Greg

"Greg" bravely wrote to "All" (22 Aug 04 09:31:02)
--- on the heady topic of "Pioneer SX-9000 Problems"

Gr From: Greg

Gr Hi,

Gr I recently came into possession of a 1970 Pioneer SX-9000 receiver.
Gr While trying it out I found that when changing the volume a loud
Gr crackling sound was coming out of the speakers. I researched the
Gr issue and found it was most likely due to dirty contacts, I tried
Gr some tuner spray but it didn't do anything. I also noticed a hissing
Gr sound coming out of the speakers when no music was being played and a
Gr "clunk" noise when turning the unit off. At this point, I contacted a
Gr local electronics repair shop and took it in for an estimate. They
Gr gave me an estimate to clean the contacts and replace a few capacitors
Gr that were bad. Well, I picked up the unit yesterday and 95% of
Gr cracking is gone and no more clunking happens when powering the unit
Gr off. However, the hiss remains. In the google archives, I found the
Gr following:

Gr http://groups.google.com/groups?q=pi...l=en&lr=&ie=UT
Gr F-8&selm=d2e5798e.0203062230.7339362e%40posting.goog le.com&rnum=1

Gr The problems outlined in this post are mostly what is happening to
Gr mine. The one thing I can add is the hissing gets much worse in one
Gr channel as the receiver warms up. Within 15 minutes, the hiss becomes
Gr noticeable and starts to degrade the sound of the music coming out of
Gr that channel.

Gr Any suggestions on what I should do to fix this? The above repairs
Gr already cost me $65 and I don't want to put much more money in to
Gr this. My electronics skills are minimal (I can solder a bit), so if I
Gr knew exactly where the problem was I could try to fix it myself.
Gr Also, do I have a beef with the repair shop?

Gr Any advice and suggestions would be helpful.

Gr Thanks,

Greg, the shop didn't do a very thorough job but then again this type
of restoration work isn't very cost effective from their viewpoint, so
I can't really blame them as it probably cost them more than the $65
in time alone. I'm afraid a 70's receiver is a nicely complex piece of
equipment. However, you might try to narrow down the problem as to the
tuner or the audio circuitry. One question is, does the hiss exist only
in FM or also in AM or when set to AUX, or when the volume is at zero?

A+s+i+m+o+v

.... 'Keep the smoke inside.' -- 1st Rule of Electronics.

Gr The one thing I can add is the hissing gets much worse in one
channel as the receiver warms up. Within 15 minutes, the hiss becomes
Gr noticeable and starts to degrade the sound of the music coming out of
Gr that channel.

Gr Any suggestions on what I should do to fix this? The above repairs
Gr already cost me $65 and I don't want to put much more money in to

Greg, the shop didn't do a very thorough job but then again this type
of restoration work isn't very cost effective from their viewpoint, so
I can't really blame them as it probably cost them more than the $65
in time alone. I'm afraid a 70's receiver is a nicely complex piece of
equipment. However, you might try to narrow down the problem as to the
tuner or the audio circuitry. One question is, does the hiss exist only
in FM or also in AM or when set to AUX, or when the volume is at zero?


The hiss is present regardless of what mode (phono, FM, AM, etc) the
receiver is in, which set of speaker outputs are used, and whether the
volume is high or low.

Thanks,

Greg



A+s+i+m+o+v

... 'Keep the smoke inside.' -- 1st Rule of Electronics.

Does this receiver have a separate pre-amp to power amplifier output at the
rear? If so, then check out the signal coming from the pre-amp before it
enters the power amp by using another units power amp. You can usually feed
the signals from the pre-amp output to another units AUX input. If the hiss
is gone, then the problem has been narrowed to the power amp. If the hiss
remains, then the problem is in the pre-amp. Having a schematic and an
oscilloscope would help you find the source of the hiss. Since you have one
good channel and another one that is bad you can compare signals.

The source of the noise could still be a dirty connector, switch,
potentiometer, a coupling capacitor as was previously suggested, or even a
defective filter capacitor or bad ground.

Good luck.

Bob

"Brine" wrote in message
om...
Gr The one thing I can add is the hissing gets much worse in one
channel as the receiver warms up. Within 15 minutes, the hiss becomes
Gr noticeable and starts to degrade the sound of the music coming out
Gr of that channel.

Gr Any suggestions on what I should do to fix this? The above repairs
Gr already cost me $65 and I don't want to put much more money in to

Greg, the shop didn't do a very thorough job but then again this type
of restoration work isn't very cost effective from their viewpoint, so
I can't really blame them as it probably cost them more than the $65
in time alone. I'm afraid a 70's receiver is a nicely complex piece of
equipment. However, you might try to narrow down the problem as to the
tuner or the audio circuitry. One question is, does the hiss exist only
in FM or also in AM or when set to AUX, or when the volume is at zero?

The hiss is present regardless of what mode (phono, FM, AM, etc) the
receiver is in, which set of speaker outputs are used, and whether the
volume is high or low.

Bob Shuman wrote:
Does this receiver have a separate pre-amp to power amplifier output
at the rear? If so, then check out the signal coming from the
pre-amp before it enters the power amp by using another units power
amp. You can usually feed the signals from the pre-amp output to
another units AUX input. If the hiss is gone, then the problem has
been narrowed to the power amp. If the hiss remains, then the
problem is in the pre-amp. Having a schematic and an oscilloscope
would help you find the source of the hiss. Since you have one good
channel and another one that is bad you can compare signals.

I believe(?) that this particular one has pre/main jumpers (they would be a
set of RCA jacks in the back with a piece of wire jumping them together).
Merely removing those would isolate the problem considerably. If the hiss
remains with the jumpers pulled, it's definitely in the preamp section.
Flipping the tape monitor switch 'on' would also isolate part of the preamp.

jak


The source of the noise could still be a dirty connector, switch,
potentiometer, a coupling capacitor as was previously suggested, or
even a defective filter capacitor or bad ground.

Good luck.

Bob

"Brine" wrote in message
om...
Gr The one thing I can add is the hissing gets much worse in one
channel as the receiver warms up. Within 15 minutes, the hiss
becomes
Gr noticeable and starts to degrade the sound of the music coming
out Gr of that channel.

Gr Any suggestions on what I should do to fix this? The above
repairs Gr already cost me $65 and I don't want to put much more
money in to

Greg, the shop didn't do a very thorough job but then again this
type of restoration work isn't very cost effective from their
viewpoint, so I can't really blame them as it probably cost them
more than the $65
in time alone. I'm afraid a 70's receiver is a nicely complex piece
of equipment. However, you might try to narrow down the problem as
to the tuner or the audio circuitry. One question is, does the hiss
exist only in FM or also in AM or when set to AUX, or when the
volume is at zero?

The hiss is present regardless of what mode (phono, FM, AM, etc) the
receiver is in, which set of speaker outputs are used, and whether
the volume is high or low.

jakdedert wrote:
Bob Shuman wrote:
Does this receiver have a separate pre-amp to power amplifier output
at the rear? If so, then check out the signal coming from the
pre-amp before it enters the power amp by using another units power
amp. You can usually feed the signals from the pre-amp output to
another units AUX input. If the hiss is gone, then the problem has
been narrowed to the power amp. If the hiss remains, then the
problem is in the pre-amp. Having a schematic and an oscilloscope
would help you find the source of the hiss. Since you have one good
channel and another one that is bad you can compare signals.

I believe(?) that this particular one has pre/main jumpers (they
would be a set of RCA jacks in the back with a piece of wire jumping
them together). Merely removing those would isolate the problem
considerably. If the hiss remains with the jumpers pulled, it's
definitely in the preamp section. Flipping the tape monitor switch
'on' would also isolate part of the preamp.

OOPS...make the above 'the power amp section.'

jak


The source of the noise could still be a dirty connector, switch,
potentiometer, a coupling capacitor as was previously suggested, or
even a defective filter capacitor or bad ground.

Good luck.

Bob

"Brine" wrote in message
om...
Gr The one thing I can add is the hissing gets much worse in one
channel as the receiver warms up. Within 15 minutes, the hiss
becomes
Gr noticeable and starts to degrade the sound of the music coming
out Gr of that channel.

Gr Any suggestions on what I should do to fix this? The above
repairs Gr already cost me $65 and I don't want to put much more
money in to

Greg, the shop didn't do a very thorough job but then again this
type of restoration work isn't very cost effective from their
viewpoint, so I can't really blame them as it probably cost them
more than the $65
in time alone. I'm afraid a 70's receiver is a nicely complex piece
of equipment. However, you might try to narrow down the problem as
to the tuner or the audio circuitry. One question is, does the hiss
exist only in FM or also in AM or when set to AUX, or when the
volume is at zero?

The hiss is present regardless of what mode (phono, FM, AM, etc) the
receiver is in, which set of speaker outputs are used, and whether
the volume is high or low.

On Mon, 23 Aug 2004 10:37:37 -0500, "Bob Shuman"
wrote:

Does this receiver have a separate pre-amp to power amplifier output at the
rear? If so, then check out the signal coming from the pre-amp before it
enters the power amp by using another units power amp. You can usually feed
the signals from the pre-amp output to another units AUX input. If the hiss
is gone, then the problem has been narrowed to the power amp. If the hiss
remains, then the problem is in the pre-amp.

It has outputs marked "pre amp & mixing record". Setting the SX-9000
on FM, when I run cables from that to my Harmon Karden HK395i
receiver/amp's tape in I don't hear anything (including hiss).
However, if I run these same cables from the SX-9000's "Tape A Rec"
outs to the HK's tape in, I can hear the FM signal (with no hiss).
Does this mean the pre amp is broken? Would I get any sound out of
the Pioneer amp if the pre-amp was shot?

Thanks,

Greg

"Greg" wrote in message
...
On Mon, 23 Aug 2004 10:37:37 -0500, "Bob Shuman"
wrote:

Does this receiver have a separate pre-amp to power amplifier output at
the
rear? If so, then check out the signal coming from the pre-amp before it
enters the power amp by using another units power amp. You can usually
feed
the signals from the pre-amp output to another units AUX input. If the
hiss
is gone, then the problem has been narrowed to the power amp. If the
hiss
remains, then the problem is in the pre-amp.

It has outputs marked "pre amp & mixing record". Setting the SX-9000
on FM, when I run cables from that to my Harmon Karden HK395i
receiver/amp's tape in I don't hear anything (including hiss).
However, if I run these same cables from the SX-9000's "Tape A Rec"
outs to the HK's tape in, I can hear the FM signal (with no hiss).
Does this mean the pre amp is broken? Would I get any sound out of
the Pioneer amp if the pre-amp was shot?

Thanks,

Greg


All it means is the problem isn't in the FM section. The record-out jacks
are right after the selector switch.

Mark Z.