Tom,
The symptom you describe could be caused by a bad ON switch or by a problem
with the microprocessor. Try unplugging the AC power from the amp, waiting a
minute or two, then replugging. If there's a problem with the
microprocessor, this might reset it.
If that doesn't work, try communicating with the microprocessor through the
RS-232 interface using either a comm program like HyperTerminal or
AlphaRemote. If you haven't used the RS-232 port before, check the manual
for proper cable pinout. Once you have the 87A connected to your PC, run
AlphaRemote and configure it for the COM port and baud rate (4800.) If the
microprocessor is dead or is not communicating with AlphaRemote, the program
will show zeros for all parameters, like TUNE, LOAD, FREQ (check the cable,
COM port configuration, baud rate, etc.) If the program shows values for
these parameters, then it is communicating with the microprocessor. You can
then use the power on button in AlphaRemote to turn on the amp. If this
works, then the ON switch probably has a mechanical problem and you will
have to remove the front panel to fix or replace (it's not difficult to
remove the panel.) If the amp does not turn on, then something more
fundamental is going on.
If you don't have AlphaRemote, run HyperTerminal and configure it for the
appropriate COM port and 4800 baud. When you hit <ENTER> the amp will
respond with "SYNTAX ERROR". If it does that, the microprocessor is OK. If
not, then either the microprocessor is dead or is not communicating with
HyperTerminal (check the cable, COM port configuration, baud rate, etc.)
Type AC ON<ENTER> to turn on the amp. If this works, then the ON switch
probably has a mechanical problem and you will have to remove the front
panel to fix or replace (it's not difficult to remove the panel.) If the amp
does not turn on, then something more fundamental is going on.
73, Dick WC1M
> -----Original Message-----
> From: TNeill1648@aol.com [mailto:TNeill1648@aol.com]
> Sent: Sunday, February 06, 2005 2:30 PM
> To: amps@contesting.com
> Subject: [Amps] Alpha 87A Problem
>
>
> I am experiencing my first ever problem with my 87A. The
> problems appears to
> be the "ON" switch not functioning properly.
>
> The amp was working fine when I turned it off but failed to
> turn ON the next
> day. Fuses are OK and the amp is getting AC power. The
> internal fuse by the
> AC strip next to the rear panel is OK also.
>
> Wonder if anyone knows of a method of checking the "ON"
> switch without
> removing the front panel or if you might know of something
> else to check.
>
> Thanks for the assistance.
>
> Tom K4XG
>
>
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