----- Original Message -----
From: "Rick Stealey" <rstealey@hotmail.com>
To: <amps@contesting.com>
Sent: Sunday, April 24, 2011 1:08 PM
Subject: Re: [Amps] Blown anode choke in TL-922
>
> The slow roast is indicative of a resonance that is far enough away that
> it
> doesnt instantly blow apart.
Carl,
By this you mean when he is operating on a band near where the choke is
resonant
the choke is taking some of the RF and heating up? Makes sense.
** Thats what I suspect, Ive seen similar with other amps when the WARC
bands opened.
But how do you account for the fact that it popped when he wasn't even on
the air?
The amp was just idling, not even keyed up, and he hit the LV/HV switch.
Where
was the path for B+ to ground?
I'm thinking he has two issues, possibly. One related to the RF choke and
another
which could be a gassy 3-500 or a failing coupling cap.
** Tube arc likely, excessively high current took it out. Tube may still be
OK but when they are run a long time without degasing by running the anode
red its harder to restore them. Thats when I run them at much lower HV and
run the grid bias positive in order to raise the plate current.
A leaky plate blocking cap would take out the safety choke, its something to
check.
Carl
KM1H
Rick K2XT
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