Phil Allison wrote:
David Farber wrote:

------------------------

This Rickenbacker RM112P monitor amp came to me with the complaint
that it randomly crackles and pops. I plugged it in this afternoon
and of course it didn't make any pops or crackles. I disassembled it
and cleaned the controls. They were only slightly noisy. I was
unable to locate a schematic for it. If it does decide to break down
and make the noises, I would like to be able trace the signal. Does
anyone have a link for a schematic? It's very clean inside. There
are a few potential problem places that I see. One is that there is
double sided sticky tape holding the filter capacitors in place. The
p.c. trace is not insulated and I was wondering if that could be
causing a problem. Secondly, there seems to be some type of chemical
reaction happening leaving a flakey orange substance where some of
the components are connected to the circuit board.

http://webpages.charter.net/mrfixite...-terminals.jpg

http://webpages.charter.net/mrfixite...ilter-caps.jpg

Thanks for your reply.


** Good servicing practice requires that you FIRST observe a fault
before delving inside to find the cause.

Consider that the unit may have no fault at all, the reported noises
being fed in from an external device and / or are due to AC supply
transients.


.... Phil

Hi Phil,

I would agree with you up until the point where after several days of
waiting, and no faults are exhibited, then a peek inside the unit might give
you a clue. Maybe something spilled inside, or perhaps another tech might
have done some creative repairs. I haven't mentioned until now but I did
find this (photo links below) sitting in the wide open space below the
speaker inside of the amp box. I don't think it belongs inside the amp. But
even if it's loose inside, I still don't think it would cause popping and
crackling noises. Can you identify what it is? It looks to me like it is
from a wall attachment for a telephone.

View 1
http://webpages.charter.net/mrfixite...y-object-a.jpg

View 2
http://webpages.charter.net/mrfixite...y-object-b.jpg

Thanks for your reply.
--
David Farber
Los Osos, CA