Date: Sat, 4 Jun 2022 13:26:32 +0000 (UTC)
From: "gudguyham@aol.com" <gudguyham@aol.com>
To: Shane Youhouse <kd6vxi@gmail.com>, Victor Rosenthal 4X6GP
<k2vco.vic@gmail.com>
Cc: Amps reflector <amps@contesting.com>
Subject: Re: [Amps] Why does power output increase?
## what is the idle current ??? Try it on SSB (hi voltage)...and also on
CW (low voltage). IE: put xcvr on SSB, mic gain on zero, key the PTT.
## IF the resistor in the fil primary heated up, it's resistance would
INcrease, not decrease. Tube emission would decrease. PO would drop, not
increase.
## Your bias vdc may be screwed up..and changing with a load applied.
Even this doesn't make sense. Typ, when zeners fail, I believe they typ
fail shorted....which would result in sky high idle current. Which would
make it easier to drive the amp.
## But in this case, it's as though the zener V starts off normal, then
decreases, and I find that hard to believe. Something else is amiss, and
it maybe one or both tubes has gone wonky.
## do u have a dead on wattmeter to test with....or a scope ?
## The zener has to handle cathode current....which is the sum of the plate
and grid current. I'd replace the zener with a string of 1N5408's. I
have had no luck with zener's.
Jim VE7RF
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