Weird speaker problem

[pepebuho]

Hi
I have a weird speaker problem. These are the speakers of a mini
stereo system.

The speakers are kind of old. We are talking 10+ years.

Generally they work fine. But if I somehow touch/move the table where
they are resting, they turn off. Nothing I do (shake, move, vibrate)
wil make them turn back on.
But if I just turn up the volume, eventually they come back to life. I
can lower the volume back to its former level and they continue
working normally like nothing happened.

What could it be? Other than that, the speakers sound fine. I thought
about a loose/broken wire somewhere but I do not see how turning up
the volume would fix it in such a way that lowering back the volume
does not "unfix" it.

It seems too weird even for google.

 

On 2012-02-24 07:59:10 +0100, pepebuho <pepebuho@gmail.com> said:

Hi
I have a weird speaker problem. These are the speakers of a mini
stereo system.

The speakers are kind of old. We are talking 10+ years.

Generally they work fine. But if I somehow touch/move the table where
they are resting, they turn off. Nothing I do (shake, move, vibrate)
wil make them turn back on.
But if I just turn up the volume, eventually they come back to life. I
can lower the volume back to its former level and they continue
working normally like nothing happened.

What could it be? Other than that, the speakers sound fine. I thought
about a loose/broken wire somewhere but I do not see how turning up
the volume would fix it in such a way that lowering back the volume
does not "unfix" it.

It seems too weird even for google.

surely bad contacts in the volume potentiometer...
a current problem ...
change the potentiometer if possible, of use a contact spray
--
----------
Kripton

the ESR Repository @ http://kripton2035.free.fr/esr-repository.html
the Geiger Repository @ http://kripton2035.free.fr/geiger-repositor.html

 

[Ron]

On 24/02/2012 06:59, pepebuho wrote:

Hi I have a weird speaker problem. These are the speakers of a mini
stereo system.

The speakers are kind of old. We are talking 10+ years.

Generally they work fine. But if I somehow touch/move the table
where they are resting, they turn off. Nothing I do (shake, move,
vibrate) wil make them turn back on. But if I just turn up the
volume, eventually they come back to life. I can lower the volume
back to its former level and they continue working normally like
nothing happened.

What could it be? Other than that, the speakers sound fine. I
thought about a loose/broken wire somewhere but I do not see how
turning up the volume would fix it in such a way that lowering back
the volume does not "unfix" it.

It seems too weird even for google.

It's a high resistance contact somewhere. You haven't given enough
information for a more accurate diagnosis but my guess would be that
there is an output relay or a connector with either tarnished or worn
(low pressure) contacts. Turning up the volume allows the increased
voltage to break down the insulating layer for a while.

Giving a make and model might be helpful


Ron

 

[spamtrap1888]

On Feb 23, 10:59 pm, pepebuho <pepeb...@gmail.com> wrote:

Hi
I have a weird speaker problem. These are the speakers of a mini
stereo system.

The speakers are kind of old. We are talking 10+ years.

Generally they work fine. But if I somehow touch/move the table where
they are resting, they turn off. Nothing I do (shake, move, vibrate)
wil make them turn back on.
But if I just turn up the volume, eventually they come back to life. I
can lower the volume back to its former level and they continue
working normally like nothing happened.

What could it be? Other than that, the speakers sound fine. I thought
about a loose/broken wire somewhere but I do not see how turning up
the volume would fix it in such a way that lowering back the volume
does not "unfix" it.

It seems too weird even for google.

You may be jumping to conclusions. Is the entire stereo sitting on the
table or are just the speakers? If the entire stereo is sitting on the
table, then I agree with the other poster that th volume control wiper
may not be making good contact. When you hit the table the wiper may
move over a dead spot on the pot.

 

[pepebuho]

It is a Panasonic SA-AK15 mini system. The body (cd changer, tape
deck, tuner) is on a shelf and the speakers (two) are hooked through
long cables on another shelf, atop my bed headboard.

 

[Ron]

On 25/02/2012 07:10, pepebuho wrote:

It is a Panasonic SA-AK15 mini system. The body (cd changer, tape
deck, tuner) is on a shelf and the speakers (two) are hooked through
long cables on another shelf, atop my bed headboard.

If, after a couple of second after you switch the unit on, there is a

quiet mechanical click. that would indicate a relay (which generally
isolates the speakers). That would be my first port of call, checking
for low contact pressure or tarnished contacts.
Tapping this relay often provides a clue. If the fault always occurs on
both channels simultaneously, then I would suspect that the relay isn't
the cause

It's easier usually to replace the relay than fiddle around trying to
improved the contact arrangements.

I would inspect any ribbon cables especially the flat 'printed' type for
tarnished contact areas on the ends.

Another area in which it might be fruitful to look, is any mechanical
push switches, tho these are becoming rare on modern equipment.

The other possibility is a dry joint (cold solder joint), which would
probably be anywhere in the signal path after the volume control, and
somewhere common to both channels.

HTH

Ron