Will -- It was bandswitch arcing. Tube arcing was due to
"barnacles" - which sounds like a sea story to me after having
autopsied tubes that supposedly arced from this malady. .
- Someone -
On Jul 7, 2004, at 3:56 PM, Will Matney wrote:
Well,
I'd say it was the tube arced internally first thought. I wouldn't
discount parasitics causing this either. There's not too many things
that cause a loud pop in an amp. If it were an electrolytic capacitor,
you'd smelled a real sour smell coming from the amp and foil with
paper would be everywhere it "once" was. If the coupling cap shorted,
it should have blown a fuse. If the tube did arc, it would have blown
a grid resistor if that amp has them. Some uses a choke and some none
at all. Let's put it this way about parasitics, MFJ the manufacturer
of your amp threatened a law suit over someone even mentioning
parasitics causing tube and band switch arcing! Now that should tell
you something about it.
Will
"Subject: [Amps] AL-1200 Pop
I just finished replacing the open frame relay in my old AL-1200 with
the Ameritron relay PCB mod. Put it all back together, seemed to work
fine,tuning on 40m. Moved to 160m, had the Amp in Standby while I set
the output power on the exciter. Heard a loud Pop - exciter power
only.I turned the Amp off for awhile, then tried it again. It still
works fine.I opened it up looking for a visibly bad component, none
found. Any ideas what this might have caused a Pop in Standby? Should
I worry?"
Dana
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