Help needed fixing Sansui AU-101 amp

[Asimov]

"Alisdair" bravely wrote to "All" (13 Sep 03 18:38:54)
--- on the heady topic of "Help needed fixing Sansui AU-101 amp"

Being an old amp and assuming it has been sitting unused for a long
while, I would highly suspect the most typical problem being marginal
aluminum can electrolytic capacitors. You have to ESR every electro in
the amp and change all that turn up bad. Only then you can go on to
diagnose other faults. Everyone here will offer the same advice.


Al> From: Alisdair <[email protected]_spam_me.me.uk>

Al> hi,

Al> I've just got an old Sansui AU-101 amp, and it has a few problems:
Al> - there's no output on the right channel until it's been on a few
Al> minutes - both channels (but particularly the right) crackle when
Al> balance or volume are adjusted. Once the unit has warmed up the
Al> problem with the volume goes away.

Al> The sound quality is ok though once it's warmed up.

Al> I've done some searches and found suggestions for similar situations,
Al> like freezing transistors or replacing caps (largest first), any idea
Al> what to try first? I've done some electronics in the past so I'm not
Al> completely ignorant, never tried to recondition a hi-fi before though.

Al> I'd appreciate any suggestions as to what to try, especially related
Al> to the AU-101 in particular.

Al> Thanks,

Al> Alisdair

.... A fail-safe circuit will destroy others.

 

[Mark D. Zacharias]

Smaller caps near a heat source, yes. Others, probably not.

Dirty controls & switches, number one.
Solder connections, number two.

Other, more obscure sources of bad connections, number three. I worked on an
old Sansui integrated (sorry-don't remember the model number) on which the
B+ voltage for the outputs was lost intermittently due to bad physical
connections to the TO-3 devices.

A tech could probably fix it in pretty short order. A do-it-yourself-er,
well, maybe, maybe not.

Mark Z.

 

[Alisdair]

Smaller caps near a heat source, yes. Others, probably not.

Dirty controls & switches, number one.
Solder connections, number two.

Succinctly put, will do.

A tech could probably fix it in pretty short order. A do-it-yourself-er,
well, maybe, maybe not.

Well, I'll learn something, whichever way it goes. Thanks for the advice.

Alisdair