Hi everybody,
I've got a 87A that I bought already broken. Together with a friend I am
currently trying to get it back to life.
From our first diagnostics it looked like almost all logic on the motor
driver board was broken. We think that the reason was that in the past
somebody connected Jumper J3 on the motor driver board shifted by one
pin and in that way connected the +5V of the logic to the +36V for the
motors.
We replaced all the logic on the motor driver board and on the switch
board including two PALs that I ordered from RFConcepts. For now it
looks like the motor driver board is ok. Unfortunately the amp still can
not be controlled by the switches on the front panel.
The two PALs on the motor driver board that we already replaced seem to
do some multiplexing for the keys and are alternately polled by the two
signals PAL1 and PAL2. These signals are generated by the PAL U10 on the
microprocessor board. It looks like that this PAL (and hopefully only
that one) also has been damaged.
Sure I can ask RFConcepts to also send this PAL, but as shipping of the
IC is almost twice as expensive as the IC itself I'm looking for the
sourcecode of this PAL (or even better of all PALs). I have empty PALs
and a programmer at hand and so that would be much more convenient.
Maybe there is someone on the list who has the sourcecode available.
Thanks in advance es vy 73
Simon, DJ4MZ
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