Setting Up Alpha 87A Communications to PC
Please unplug the 87A for 1 minute and then plug it back in
to the 240v. This will reset the microprocessor and can
sometimes correct erratic operation (possibly caused by stray
RF), although it will NOT clear hard faults or remove them from
the fault log.
The 87A should 'talk' to the PC anytime it is plugged into mains
power, even when it is turned off. This is the best
troubleshooting tool that we have. Note that the 20A fuses must
be good.
Below are some notes about the 87A fault protection.
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Please remember that when the 87A gets a hard fault and
then the power is turned back on, it will report the fault for 30
seconds and then clear automatically. You must not turn off the
power before the fault clears (about 30 seconds), or it will log
another hard fault the next time the power is turned on.
Also remember that six of the SAME hard fault shutdowns over
ANY period of time (with no other kind of Hard fault) will then put
the 87A in Fault 99 which locks it up. This function was put in the
amplifier to prevent any further damage if operation was
attempted after a failure had occurred.
If you keep turning off the power before a hard fault has
cleared, and this causes 6 of the same hard faults to be entered in
the fault log, the 87A will then go into Fault 99 and will not turn on.
Also, if the 87A is turned on 6 times when it keeps shutting
down immediately because of a hard fault, it will go into Fault 99.
Once the 87A is in Fault 99 condition, each time the ON switch
is pressed it logs another Fault 99. After 8 times, the original
hard fault will have been shifted out of the fault log, it will only
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