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Re: [Amps] Alpha 77SX forward & reverse W not working

Subject: Re: [Amps] Alpha 77SX forward & reverse W not working
From: Martin Sole <>
Date: Sat, 30 Mar 2019 22:45:03 +0700
List-post: <>
I had the same problem with my early 77D, so early the fwd ad rfl meter is open wired on tag strips, no pcb. I just replaced the diodes, seems they have a finite life. Likely you have a similar problem. I had the detector diodes go in my Alpha 78 as well a while ago.

Martin, HS0ZED

On 29/03/2019 09:34, Gary Smith wrote:
Another hiccup in getting this old girl
back into shape. I rarely use the watt
meter in the amp, I use the one in the P3
and on top of the amp is a LP-100A, those
always handle my needs. As a general rule
I leave the multimeter in the Grid setting
and always use that.

When I had a look see in the amp to see
what was what was going on with the
padding caps, all seemed to go well, no
unexpecteds happened but with reassembly I
tried using the watt meter and found it's
barely working; the meter moves but very
little. The last time I used it 4-5 months
ago, it worked well.

No telling if I somehow bumped something
but is there a likely first thing to look
at? The meter movement is fine, works
seamlessly with grid current.



P.S. I received all the new  High Energy
7.5KV 9A doorknobs to replace the old
Jennings and Centralab 1A variety. Waiting
for the Ameritron choke and some silver
plated flat wire to come in and I'll get
them installed. It'll be nice to have the
tank upgraded.
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