"N_Cook" wrote in message
...
I don't remember seeing this since the days of wired-in VCR remotes. A
chain
of R varying from 680R to 10K for 11 of the main key switch sensing, not
diode array. That single resistance-set control line goes through the 14
pin
lift-off front panel connection to the main micro. Was thinking if outside
the allowed range, or dirty contacts, then perhaps an illegal mode, but
they
check out true considering E12 series. High probability of a break
somewhere
in such a chain of SM resistors.



I have seen this scheme of button sensing on many audio units, particularly
of Sony manufacture. Makes for very simple software to determine which
button has been pressed. The CPU only needs to read a single A-D input pin,
and then compare the result to a lookup table programmed with what function
belongs to what sensed voltage.

Arfa