pioneer sx-950 intermittent problem, how to fix.

s saroff

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Jan 1, 2003, 7:53:39 PM1/1/03

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Hello,

I have a Pioneer sx-950 receiver which has the following intermittent
problem:

Sometimes the right hand channel losses most of its volume, or goes
completely dead. Sometimes there is a slight crackling sound on this
channel as well.

I am able to "fix" the problem by lightly hitting the side of the
radio with my hand!

Most of the time the radio works wonderfully and sounds excellent. It
puts to shame my newer, more expensive receivers.

Any advice would be great. I would also appreciate being pointed to a
good source for a service manual and schematic. I also own an sx-580
and sx-939 and need service manuals for these radios as well.

thank you.
steve saroff

D.Cabaniss

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Jan 1, 2003, 8:00:55 PM1/1/03

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"cold" solder joint I'd guess, whip out the iron and start dabbing a few
spots on the board, start with the power capacitors and the wire twist
terminals......
DC

"s saroff" <ssa...@hotmail.com> wrote in message
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RoyB

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Jan 1, 2003, 9:20:06 PM1/1/03

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"s saroff" <ssa...@hotmail.com> wrote in message
news:34987415.0301...@posting.google.com...

Push the "tape monitor" button in and out about 25 times. If this does not
take care of it but improves it, you will need some contact cleaner for the
switch. Cracked solder joints can also cause this malady, sometimes they
will be visible on the circuit board by locating an area that has turned
brown from the heat build-up due to the bad connections, the bad joints will
have an extra "circle" between the lead and the outer edge of the solder. I
think a lot of people are looking for a crack as in "broken glass", but once
you have seen one, they become easy to spot. Just be careful not to bridge
two solder joints together............

Good luck!

Roy

Pete KE9OA

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Jan 2, 2003, 2:27:18 AM1/2/03

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If your receiver has a turn-on delay that uses a relay, that could also be a
cause. If the contacts have become oxidized, it will exhibit this symptom.

Pete

dxqq62

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Jan 2, 2003, 6:50:35 AM1/2/03

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Hey Steve,
Here's the website to obtain the service manuals for your Pioneer Receivers.
http://www.stereomanuals.com/manuals/pioneer/pioneer_all-2.htm
Here's the front page to that site.
http://www.stereomanuals.com/
Enjoy Steve.....
Vince

dxqq62

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Jan 2, 2003, 11:27:25 AM1/2/03

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Here's another site for service manuals.
http://www.tech-wiz.com/index.htm
Vince

Neil

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Jan 2, 2003, 2:28:22 PM1/2/03

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"RoyB" <bias...@prodigy.net> wrote in message news:<qlNQ9.1198$ns3...@newssvr19.news.prodigy.com>...

> "s saroff" <ssa...@hotmail.com> wrote in message
> news:34987415.0301...@posting.google.com...
> > Hello,
> >
> > I have a Pioneer sx-950 receiver which has the following intermittent
> > problem:
> >
> > Sometimes the right hand channel losses most of its volume, or goes
> > completely dead. Sometimes there is a slight crackling sound

Possibly dirt in the controls. This is a '70's receiver, isn't it?
Then there's been plenty of time for dirt and oxidation to be in the
controls. These are typical problems as electronics age. Been there,
done that!

> on this
> > channel as well.

(snip)

> Push the "tape monitor" button in and out about 25 times. If this does not
> take care of it but improves it, you will need some contact cleaner for the
> switch.

I suggest you unplug the Pioneer and disconnect all components from
it. Let the Pioneer sit for maybe 30 minutes. Then remove the top
cover. With some spray contact cleaner (available for maybe $5 USD
from Radio Shack and many other places that sell electronic supplies),
go through the Pioneer and spray all the contacts and switches, volume
and tone controls, everything like that, and all the contacts, speaker
connections etc. on the back of the unit.

Then let the Pioneer sit a few hours so the cleaner can evaporate.
Next, connect the Pioneer to your other gear (or just use headphones
instead) and listen and find out if the problem is gone.

If the above doesn't fix the problem, you may have to go through all
of the above several times. If the contact cleaner doesn't work, then
you may have a bad solder connection or other problem. See below:

>Cracked solder joints can also cause this malady, sometimes they
> will be visible on the circuit board by locating an area that has turned
> brown from the heat build-up due to the bad connections, the bad joints will
> have an extra "circle" between the lead and the outer edge of the solder. I
> think a lot of people are looking for a crack as in "broken glass", but once
> you have seen one, they become easy to spot. Just be careful not to bridge
> two solder joints together............

Good point. With the soldering iron, it's also possible to cause some
serious problems or wreck the Pioneer. If you're not comfortable with
a soldering iron, take the Pioneer to a repair shop.

A newsgroup for repair help:

rec.audio.tech

And remember, when you do anything to fix the Pioneer, make sure it's
disconnected from the wall socket and all of your stereo components!