Don't know why you'd smell anything if it was a "tuned input"
problem...although I suppose the little slug-tuned inductor could go "poof,"
or the mica caps could flash -- but I'd think that would happen just once,
and stop happening, and there isn't much material there to burn.
Sounds more like an output tank problem.
What does the 3CX1200 plate current and grid current indicate when he
*tries* to operate on 80m (apply just a little drive, to see if Ip and Ig
rise to indicate anything)?
Normally a "bad smell" is from stuff burning up due to lots of DC input
power with very little or no RF output power, so all the power consumed is
dissipated in the box....
-WB2WIK/6
"There is no reason anyone would want a computer in their home." - Ken
Olson, Chairman & Founder, Digital Equipment Corporation (1977)
> -----Original Message-----
> From: K9RT@aol.com [SMTP:K9RT@aol.com]
> Sent: Wednesday, September 22, 2004 8:40 AM
> To: amps@contesting.com
> Subject: [BULK] - [Amps] AL1200
>
> Have a friend with an AL1200 that recently stopped transmitting on 80
> meters
> only. Works fine, full output on all other bands.
> He said he heard a hiss and then it stopped working on 80. I looked at the
>
> bandswitch contacts and loading coil and can see no evidence of
> burned/arcing.
> We tried to load it again yesterday and a nice burned odor permeated the
> room. No output again on 80 only.
> Any suggestions? I am leaning towards the input circuitry but he is
> dreading
> shipping it back to Ameritron.
> Any suggestions as to reputable amp service work in the midwest in the
> vicinity of Louisville, KY? He would much rather drive a little and
> deliver the
> amp rather than risk shipping this beast.
>
> Thanks for any help/advice and will pass it along as received.
>
> Dick K9RT
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