repair help needed for Stereo (Sharp)

[Svante Karlsson]

Please help a technical idiot. I have an old Sharp stereo and one of
the channels in the amplifier doesn't produce any output signal. I
seem to remember that this is a common problem that is relatively easy
to fix even for an amateur such as myself.

If any one has a clue of what to look for, please tell me.

Regards
Svante

PS. Yes, I know I should get a new stereo but for economic reason I
can't do that right now.

 

[Franc Zabkar]

Please help a technical idiot. I have an old Sharp stereo and one of
the channels in the amplifier doesn't produce any output signal. I
seem to remember that this is a common problem that is relatively easy
to fix even for an amateur such as myself.

http://repairfaq.ece.drexel.edu/REPAIR/F_audiofaqa.html
http://repairfaq.ece.drexel.edu/REPAIR/F_Pwr_Amp.html


- Franc Zabkar

 

[Richard]

Please help a technical idiot. I have an old Sharp stereo and one of
the channels in the amplifier doesn't produce any output signal. I
seem to remember that this is a common problem that is relatively easy
to fix even for an amateur such as myself.

If any one has a clue of what to look for, please tell me.

Regards
Svante

What's the model # on this Sharp?
Richard

 

[Svante Karlsson]

What's the model # on this Sharp?
Richard

It's a CMS R 330 (BK)
/Svante

 

[Svante Karlsson]

http://repairfaq.ece.drexel.edu/REPAIR/F_audiofaqa.html
http://repairfaq.ece.drexel.edu/REPAIR/F_Pwr_Amp.html


- Franc Zabkar

Perhaps a bit to advanced for me, but thanks anyway.
- Svante

 

[handyman20]

If you open it up you should see an aluminum heat sink (a large piece
of aluminum with fins for cooling) attached to it should be a
transistor with multiple legs. It is actually an IC chip. It is the
Amplifier for both the right channel and left channel. It is probly
bad. They are cheap About $20.00 for most. look at the # on it and
order one before removing the old one. Once you have a new one you can
cut the old one out and clean all the holes in the board one at a time.
then slip the new one in place and bolt it to the heat sink first
before soldering the connections. This way the soldering iron won't
overheat the new piece. The heat sink will help keep it cool!! Good
luck!

 

[Leonard Caillouet]

Actually, the reason to attach devices to the heat sink before soldering is
to avoid stress on the solder connections at the pins. You are soldering
ICs, not pipe. If the IC is getting hot enough to need the heat sink from
soldering, you need to get some lessons in soldering technique, especially
on an output IC.

Leonard

 

[Asimov]

"Leonard Caillouet" bravely wrote to "All" (08 Dec 04 20:19:08)
--- on the heady topic of "Re: repair help needed for Stereo (Sharp)"

If one can manage to make a slight bend to all pins before inserting
the IC then the cycles of thermal expansion and contraction won't
stress the IC's internal connections as much as a straight pin would.
Some IC's already come with the pins already pre-bent for this reason.

A*s*i*m*o*v


LC> Reply-To: "Leonard Caillouet" <[email protected]>

LC> Actually, the reason to attach devices to the heat sink before
LC> soldering is to avoid stress on the solder connections at the pins.
LC> You are soldering ICs, not pipe. If the IC is getting hot enough to
LC> need the heat sink from soldering, you need to get some lessons in
LC> soldering technique, especially on an output IC.

.... Life is just an eddy in the 2nd Law of Thermodynamics.