[Amps] Alpha 87A - strange power related issue

[w5cul at sbcglobal.net]

Eric,

There is an 87A Email Group.  You can find them here:

Alpha87A at groups.io

You will have to sign up for an "groups.io" account and after that you
should be able to query for the Alpha 87A group and request access.  

https://groups.io/

Hope this helps.

Thank you,

Mike
W5CUL

-----Original Message-----
From: Amps <amps-bounces at contesting.com> On Behalf Of Eric Dobrowansky
Sent: Sunday, October 9, 2022 7:26 PM
To: amps at contesting.com
Subject: [Amps] Alpha 87A - strange power related issue

It's been a long time, and I'm not sure if there is a dedicated Alpha 87A
related mail list in existence any longer, so I will go ahead and ask here.

I have an 87A that started exhibiting a strange problem.

When the amp is plugged in, the blower automatically starts, and various
band and segment LEDs illuminate, but the amp does not start up. The LEDs
which illuminate vary each time the amp is plugged in. 

If I try to push the POWER OFF switch, the amp will turn off the blower and
LEDs, but as soon as I release the switch, it returns to the state where the
LEDs and blower are on.

If I push the POWER ON switch, the amp starts up normally. The amp works
fine once it completes the warm-up period. 

If I then press the POWER OFF button to turn the amp off from when it is
fully running, it shuts down properly. IE - all the LEDs turn off, and the
blower stops.

However, if I leave it plugged in, out of nowhere sometime later the above
symptom repeats, and I have to pull the AC plug to get it to shut down
completely. 

Any recommendations as to where to start troubleshooting?  Maybe a cap going
bad somewhere is pulling down a particular control circuit?


Eric
K2CB

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