Giving this another shot...Labtec LCS-2412

[Mr. Land]

About 2 years ago I posted here trying to find someone who might have
schematics for a Labtec (now Logitech) LCS-2412 computer speaker
system.

Despite repeated requests from me, Labtec refused to supply them (they
were "proprietary"). When Labtec was subsequently purchased by
Logitech, whatever service materials they had on file for this unit
were apparently lost, as Logitech support informed me they were not
available.

Any suggestions on where I could look (e.g. online schematics sites)
would be much appreciated, or if someone actually has these, I'd be
willing to pay you for a copy.

Thanks.

 

[Meat Plow]

About 2 years ago I posted here trying to find someone who might have
schematics for a Labtec (now Logitech) LCS-2412 computer speaker
system.

Despite repeated requests from me, Labtec refused to supply them (they
were "proprietary"). When Labtec was subsequently purchased by
Logitech, whatever service materials they had on file for this unit
were apparently lost, as Logitech support informed me they were not
available.

Any suggestions on where I could look (e.g. online schematics sites)
would be much appreciated, or if someone actually has these, I'd be
willing to pay you for a copy.

Good luck. I would venture to say it is going to be next to
impossible to find service literature on things like your speakers which
likely would never get serviced by a third party facility. I've come to
terms that for many items there is just no service info available unless
you are a factory authorized repair center.

 

[jakdedert]

About 2 years ago I posted here trying to find someone who might have
schematics for a Labtec (now Logitech) LCS-2412 computer speaker
system.

Despite repeated requests from me, Labtec refused to supply them (they
were "proprietary"). When Labtec was subsequently purchased by
Logitech, whatever service materials they had on file for this unit
were apparently lost, as Logitech support informed me they were not
available.

Any suggestions on where I could look (e.g. online schematics sites)
would be much appreciated, or if someone actually has these, I'd be
willing to pay you for a copy.

Thanks.

I'd give it up, myself. That kind of unit is unlikely to have anything
very complicated inside anyway. If you're really set on repairing them,
buy a few 'chip amp' kits which use the same supply voltage and
substitute those for the original circuitry. Couldn't cost more than
ten or fifteen bucks. If you can ID the particular chip amps contained
in the original circuitry, buy a one of the chips and sub it out.
There's very little else to go bad in such gear.

jak

 

[Mr. Land]

Good luck. I would venture to say it is going to be next to
impossible to find service literature on things like your speakers which
likely would never get serviced by a third party facility. I've come to
terms that for many items there is just no service info available unless
you are a factory authorized repair center.

Yeah, that was the answer I sort of expected, but I thought I'd give
it
one last try. Thanks for taking the time to reply.

 

[Mr. Land]

I'd give it up, myself. That kind of unit is unlikely to have anything
very complicated inside anyway. If you're really set on repairing them,
buy a few 'chip amp' kits which use the same supply voltage and
substitute those for the original circuitry. Couldn't cost more than
ten or fifteen bucks. If you can ID the particular chip amps contained
in the original circuitry, buy a one of the chips and sub it out.
There's very little else to go bad in such gear.

jak

This unit uses multiple-op-amp DIP chips. If one or both
channels were completely dead, I think I'd be in better shape from
a troubleshooting perspective.

But it's exhibiting some weird behavior: the volume control works
normally for the right channel, but the left channel output level
remains very low as you rotate the knob. During roughly the
last 20% of the rotation of the volume control, the left channel
output level will "jump" up to match the that of the right. I've
cleaned all the pots.

The (single) tone control increases the treble of the right channel
properly, but the left channel remains "muffled" until again you
approach the maximum treble setting, at which point the left
channel emits a soft thump followed by a constant, quiet hiss
that sounds like pink noise - almost as if the tone circuit is
entering into hard oscillation at a frequency higher than I can
hear.

I guess my best bet's going to be to find some typical circuit
diagrams involving the same chips, and use those as a
troubleshooting guideline.

Thanks very much for the reply.

 

[msg]

Mr. Land wrote:

About 2 years ago I posted here trying to find someone who might have
schematics for a Labtec (now Logitech) LCS-2412 computer speaker
system.

Despite repeated requests from me, Labtec refused to supply them (they
were "proprietary").

<snip>

Unless this is some digitally controlled complex audio system, and
suspecting it is a set of conventional "computer speakers", why not
do what we all must do from time to time; open the devices, remove
the PCBs and trace the schematics. Often the time incurred is less
than the fruitless efforts at searching for the schematics
elsewhere.

Regards,

Michael

 

[Mr. Land]

<snip>

Unless this is some digitally controlled complex audio system, and
suspecting it is a set of conventional "computer speakers", why not
do what we all must do from time to time; open the devices, remove
the PCBs and trace the schematics. Often the time incurred is less
than the fruitless efforts at searching for the schematics
elsewhere.

Regards,

Michael

I thought it would be worth one more attempt at acquiring a schematic,
before I begin doing exactly what you've described.

Thank you for replying.

 

[Meat Plow]

Yeah, that was the answer I sort of expected, but I thought I'd give
it
one last try. Thanks for taking the time to reply.

Sorry I didn't have better news. But spending a majority of my adult life
as a tech I have experienced your dilemma countless times and spent
countless hours searching for solutions fruitlessly.