>Occasionally I've come across PTH where the plating has become damaged
and the two sides of the board are no longer connected.
This PCB is printed on one side only. Its lower side is in direct
contact with the metal plate on which it is screwed.
> It could well be that the resistive print in that area is faulty
either due to wear and tear, or just plain old age.
That's what I fear. I'm surprised however that only this part of this
board is concerned.
> Looking at the service manual it suggests that on either side of the
contact resistor (topologically speaking) are some resistors.
The overall circuit diagram seems wrong. Look here for what could be a
more faithful diagram AT-sensor resistors
<
http://groups.yahoo.com/group/yamahacs80/photos/album/1863574374/pic/12\73145453/view>
> If you're feeling brave you try adding a new resistor into the path to
compensate for the error?
I'll probably try that between T3 and -15.
Thanks,
Joachim
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