Rotel RA 312 from 1974
3 up/down pivoted arms opereate 3, 2 way slide switches for tape monitor
selection etc.
All 3 are now malfunctioning due to being knocked.
Its easy to slide out the slide bar of each switch and each contact is set
as manufactured,to bridge A and B , B and C but a mid position would seem to
be used.
For this amp when made the detent bits have been removed from each switch
before being used and the pcb wiring to these swutches shows that the switch
action actually used is with contacts between A and B and B and C then B-C
for off which is of course a bit iffy even when new. The 2 limit-positions
seem to be set by plastic inserts that define the upper and lower limits of
the pivotting arm in each case. Anyone come across this situation before as
it seems impossible to set one set off contacts without disturbing its
neighbour and all very iffy anyway. The contacts don't seem to be worn or
bent other than they should be.

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Diverse Devices, Southampton, England
electronic hints and repair briefs
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