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

MU 4CX250B 4cx250b at miamioh.edu
Sat Mar 30 10:40:21 EDT 2019


As I recall (and maybe I don’t!),the 77SX has the same tank circuit as
the 77DX, which means the plate load Z is too low for the tank
components. The amp tunes to resonance, except on 10m, but not certain
how good the harmonic suppression is.
Jim W8ZR

Sent from my iPhone

> On Mar 28, 2019, at 8:34 PM, Gary Smith <Gary at ka1j.com> 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.
>
> 73,
>
> Gary
> KA1J
>
> 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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