Mark D. Zacharias wrote:
Jumpster Jiver wrote:
Dan_Musicant wrote:
My 5 year old Sony MHCMG110 mini stereo has a problem:

The volume knob control doesn't always work properly. Before I open
it up I thought I'd post here and get some guidance.

The volume level heard appears to correspond correctly with the
digital level displayed, which goes from 1 to 30, maybe higher. I
never have it higher than around 20. However, when spinning the
volume knob those numbers don't always advance or decline as
expected. Sometimes they even go backwards briefly!! When using the
remote control, the volume changes smoothly and properly.

My first thought was a slipping pulley, but how would that make the
volume go the wrong way? It doesn't go the wrong way a lot and not
much - generally one digit and only momentarily when spinning the
dial. Maybe it IS a spinning pulley. Anyway, this thing is pretty
big and complex what with all the features (and I'm therefore
hesitant to open it): 60 CD changer
2 cassette bays, one recording auto-reverse
AM and FM

The speakers are separate (this is the stereo version, not 5.1 or
4.0) I bought the service manual yesterday online (they emailed it to me)
and I printed it out. It's mostly full of the schematics, but there
are parts diagrams and 3D assembly/disassembly diagrams. Looking
through the whole thing I didn't spot anything that would directly
relate to this problem. I figure I can either live with it or open
it up and try to find the problem, maybe replacing a pulley or
applying a rubber rejuvenator (recommendations?). Or, I could get a
learning remote and use IT to change the volume (the one that came
with the Sony has a kind of weak signal). I'd rather fix the
spinning control than have to use a remote. Thanks for any
guidance/help. Dan
That type of volume control uses LEDs and light sensors to detect
movement of a flat wheel with little holes in it. Either the holes
have become clogged with dust or the LEDs have gotten weak or coated
with dust. If you disassemble the control to clean it you may never
get it back together correctly or may cause it to stop working
completely, so your best bet is to use the remote control for volume
adjustments.


It's a rotary encoder constructed much like a vcr mode switch. No LED
involved. The encoder needs to be replaced, that's all.

$13.24 list from Partstore.com. Part number 1-473-392-11

Mark Z.


Yep, no leds just a real cheap multiple on off rotary slider which gets
dirty with time. Generally sealed so no air or cleaner will help. And
usually requiring just about complete disassembly of the entire unit to
get at. Have fun