I have an MCP 5500 that needs some TLC as the volume wheel (and thus bass, treble and balance) does not work .  The rest works perfectly - it was used to set up my BM7000 to act as an alarm a couple of weeks ago.

I have taken it apart and cleaned it (finding some fluff in front of the infra red Optical sensor that detects the black or white on the wheel).

I have also checked that the "cherry" microswitch (95 S1 part number 7400356) is working.  I have even tried to hold the switch on to increase or decrease the volume (not stepped as provided byt the optical switch) but to test if it works. 

Why will the volume on my BM 5500 not change when I make the switch?  Is there a feedback loop to stop the volume going to maximum if the optical sensor fails?   

Finally does anyone know if I need a new optical switch (PE1 - SFH900), micro switch or is there something else?

Brian

Sounds like the opto is gone. I have a few new ones in stock.

The switch merely tells the direction, it doesn't give pulses. The opto produces the pulses that counts the volume up or down.

Activating the switch in either direction, however, should light up the MCP without changing the volume setting, if this happens the switch is OK.

Martin

Mange tak,

The switch does not seem to activate the MCP!  Is there any way to test if it is just the opto or just the switch or both?

Brian