Help! Crackling noise from speakers.

[Matt Kissmann]

I'm hoping someone can help me! I have a Kenwood KR-9600 with a pair
of Pioneer speakers. Recently, there has been loud crackling and
hissing noises coming from my speakers (usually just one speaker).
This happens when there is no input and happens when each input is
selected with the selector knob. Any ideas? Suggestions for a fix?

[jakdedert]

Matt Kissmann wrote:
> I'm hoping someone can help me! I have a Kenwood KR-9600 with a pair
> of Pioneer speakers. Recently, there has been loud crackling and
> hissing noises coming from my speakers (usually just one speaker).
> This happens when there is no input and happens when each input is
> selected with the selector knob. Any ideas? Suggestions for a fix?

A KR-9600? That's from...what, 1976? That's old enough to be a
candidate for a good going-over. If it doesn't have deteriorating
electrolytics (likely), then at least the mechanicals and connectors
should get a once-over with Deoxit and lubrication. Also, the
protection relay could be getting oxidized and need its contacts dressed
up. One other area of concern; I've seen older units that had dried-up
heatsink compound on the output devices.

That's a pretty cool old machine--Kenwoods initial entry into the
'receiver wars' of the mid-70's. It would be a shame for something
'preventable' to take it out...perhaps irretrievably.

jak

[Richard Crowley]

"Matt Kissmann" wrote ...
> I'm hoping someone can help me! I have a Kenwood KR-9600 with a pair
> of Pioneer speakers. Recently, there has been loud crackling and
> hissing noises coming from my speakers (usually just one speaker).
> This happens when there is no input and happens when each input is
> selected with the selector knob. Any ideas? Suggestions for a fix?

Clean the selector switch. Typically, you need to do this from
inside, it is not something that can be effectively done from
the front panel. There are various specialty products made
for cleaning switches and pots. You could just try the "cheap
stuff" from Radio Shack (or equivalent) to see if that fixes (or
at least reduces) the noise. Then you can use the more serious
(and expensive) stuff if needed.

This isn't Rocket Surgery. Its rather a common disease of older
equipment like that.

[David Nebenzahl]

On 12/9/2008 9:06 PM Richard Crowley spake thus:

> "Matt Kissmann" wrote ...
>
>> I'm hoping someone can help me! I have a Kenwood KR-9600 with a pair
>> of Pioneer speakers. Recently, there has been loud crackling and
>> hissing noises coming from my speakers (usually just one speaker).
>> This happens when there is no input and happens when each input is
>> selected with the selector knob. Any ideas? Suggestions for a fix?
>
> Clean the selector switch. Typically, you need to do this from
> inside, it is not something that can be effectively done from
> the front panel. There are various specialty products made
> for cleaning switches and pots. You could just try the "cheap
> stuff" from Radio Shack (or equivalent) to see if that fixes (or
> at least reduces) the noise. Then you can use the more serious
> (and expensive) stuff if needed.
>
> This isn't Rocket Surgery. Its rather a common disease of older
> equipment like that.

Here's another idea, since I had similar problems with a receiver
(Allied, of the Allied Radio line) of similar vintage: could be that one
or more transistors have gone bad. I had just the kind of noise the O.P.
described, but only when set on "phono". Turned out to be a bad
transistor in the phono preamp section. I found the bad tranny by
tapping; the transistor had gone microphonic and made a large noise when
tapped. Try this with all the transistors. I was able to find a suitable
NTE replacement and the unit still works perfectly, now more than 30
years old.


--
Washing one's hands of the conflict between the powerful and the
powerless means to side with the powerful, not to be neutral.

- Paulo Freire