About 6 mos ago I obtained a 1997 Alpha91b from a guy that hadn't used
it since 2008 and had stored it down in his basement.
It appeared in very nice shape inside and out. Everything tested out well.
A couple of months ago, while running a contest it started it faulted
out with a high reflected power indication. I shut it down and the
following morning found that some ladderline from a 135' doublet had
shorted across one of the DX Engineering's type splice joints.
More recently it's started faulting out randomly with the same max
reflected power indication. Sometimes it'll run fine for a few hours,
sometimes right at the start. I completely disconnected the amp. from
everything and connected it to a dummy load. It did the same. Then
changed another coax and connected to another dummy load. Worked fine.
Connected it back up to the antennas and worked fine another few hours.
I was making sure it wasn't any coaxes or bad dummy loads. Faulted out
again!
I'm convinced it's the amp and not anything external now.
I haven't pulled to cover off yet to look for any physical damages.
Never heard any arcs or strange noises or smelled anything unusual. It
does this on all the bands.
What might be causing this?
thanks 73 Dwight NS9I
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