Re: Erratic output on Kenwood KR-A5030


"Sam Goldwasser" <sam@xxxxxxxxxxxxxxxxxxx> wrote in message
news:6wbq3op978.fsf@xxxxxxxxxxxxxxxxxxxxxx
"David Farber" <farberbear.unspam@xxxxxxx> writes:

"Sam Goldwasser" <sam@xxxxxxxxxxxxxxxxxxx> wrote in message
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"Gareth Magennis" <sound.service@xxxxxxxxxxxxx> writes:

"Sam Goldwasser" <sam@xxxxxxxxxxxxxxxxxxx> wrote in message
news:6w3ap19b1v.fsf@xxxxxxxxxxxxxxxxxxxxxx
This receiver seems to work fine in every respect except that the
volume
knob has to be turned up to a modest value before the speakers
come
on.
This
will occur regardless of whether the speakers are actually
enabled.

After that, it will usually run at any volume until power cycled

It has been sitting unused for about 10 years but don't know if
this
was a problem back then.

Any common issues with this model?

Thanks.



Often this is down to dirty speaker relay contacts. If it has
output
relays. Sometimes you can pop the top off them to spray the
contacts,
others are sealed and need to be replaced.

Signal relays do much the same thing by the way.

If you see any relays inside, try getting it in the state where the
speakers
aren't working and then start tapping them with a stick.

Yeah, that's what I think also. I even seem to recall this very
receiver
having that problem back before dinosaurs.....

There are two relays with covers that pop off.

Thanks! :)

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/

Power it up and don't turn up the volume. Put a scope probe at either
the
speaker relay input or the emitter resistors of the power transistors.
Turn
the volume up slowly. If you see signal before the sound comes on then
you
know it's either the relay, or speaker switch. If you see signal at the
same
time the sound comes on, then you have a different problem.

Intend to do something like that, or just clean the relay contacts!

I'm a little confused by your observation that the problem happens
whether
or not the speakers are enabled. How can you hear anything with the
speakers
disabled? Are you using headphones? Or do you mean you turn the volume
up
and down with the speakers off, then turn the speakers on, and then
everything is ok?

Turn on and no sound. Turn off Speaker A switch. Turn up volume and turn
back down. Turn on Speaker A and it works at low volume.

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

I remember the Kenwood KR-4070 had the power switch piggy backed onto the
speaker selector switch. If yours has the same design, make sure the long,
skinny, metal piece that connects the rotary switches together has not
slipped out of place. That might be contributing to the problem. This is
where hooking up your oscilloscope will answer your question in a matter of
seconds.

Good luck.
--
David Farber
David Farber's Service Center
L.A., CA


.

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