[CQ-Contest] Root cause to AL1500 band switch arcing?

[Jukka Klemola]

Hi all,
My AL1500 band switch arcs.

The symptom is similar to this video:
https://www.youtube.com/watch?v=XQRNehAJSKg

Can anyone tell me the root cause so when I fix my amplifier, I do not want
that failure to return.

Parasitic suppressor is of course missing; I am not sure parasitics are the
root cause.

My amp arcing happened when it was stand by, my left radio, band selection
40.
The amp had been stand by for some time as I was QRV on my right radio.

Symptom was some snap sounds and then it started arcing.
I switched the amplifier off really fast.

The amplifier has given me great service for a dozen contests but decided
to QRT last CQWW CW.

I have been trying to find any other failure in the amplifier - this is the
only thing I have found, so far.


73,
Jukka OH6LI