Whoops I'm not paying attention,
Hello John,
The metallic tink noise could have been the glass envelopes getting very
hot. Or the bias relay clicking.
I used to own a centurion, My front panel switches were a little wacky but
it didn't do exactly what yours is doing.
What it sounds like is the B- lead is going to ground. That will make the
plate meter read ZERO (B- metering) and it will draw NON-Biased resting
plate current. Total ZERO BIAS like 300-350 mils.
Suspect the BREAKIN KEYING MODULE and the selector switch. Ten-Tec switches
are crap and if you had a short in the Breakin module and it decided to
select breakin keying, it could do something like this.
I don't have a schematic laying around here for it anymore... But I could
look through one if I had it.
The AMPLIFIER is straight forward ham stuff except for the breakin module...
SO suspect it first, HAHAHAHA
BOB DD
-----Original Message-----
From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] On
Behalf Of Mike McCarthy, W1NR
Sent: Friday, March 09, 2007 1:47 PM
To: john
Cc: Amps@contesting.com
Subject: Re: [Amps] Centurion problems....
What is the grid current? Maybe a grid-cathode short? Maybe a weak
output relay?
Mike, W1NR
john wrote:
> I've had a recent failure with my Centurion... was operating it about 600
> watts out, when I heard a "TICK" noise (sounded mechanical, not
electrical)
> and noted that output power dropped. Plate voltage was still normal, but
no
> indicated plate current).
>
> I happened to look into the grill on the top and the PA plates were
red.
>
> Turned everything off, then back on a day later, at first all was
well,
> then the same thing happened again ...amp was normal, then output power
> dropped to exciter levels, and the plates began getting hot as
> before. I've looked beneath the sockets, and nothing seems to have gotten
> too hot here (or anywhere else)
>
> Ideas?
>
> John K5MO
>
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