Same problem here with the meter resistors.
John G4ZTR
-----Original Message-----
From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] On
Behalf Of Mike & Becca Krzystyniak
Sent: 16 July 2009 16:33
To: 'Doug Ferguson'; amps@contesting.com
Subject: Re: [Amps] Commander HF-1250 problems
Doug,
I have an early model Commander amp with a similar HV problem. Turns
out they used a type of 1 Meg metering resistors that ages. Over time the
1Meg Ohm value shifted some up 40-50% and the 1 Megs shifted up to 1.5Meg
ohm. I bought some new 1 meg ohms from Mouser, replaced all the old ones,
and my reported 1800V went back up to 2700V more or less. Caveat emptor:
This may or may not be your problem.
Regarding your power output, going to 220v might help some. Don't give
up on the amp. Aside from the resistor problem, mine has not skipped a beat
in 15 years...
73's Mike K9MK
-----Original Message-----
From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] On
Behalf Of Doug Ferguson
Sent: Thursday, July 16, 2009 1:30 AM
To: amps@contesting.com
Cc: thenewt@msn.com
Subject: [Amps] Commander HF-1250 problems
I'm new to HF amps. and have a couple questions about a Commander HF-1250. I
just bought
one, used of course, with no manual. Found one online and it says the plate
current at idle
should be about 2800V. My meter is reading about 1800V and I'm only able to
get about 850W
output on 20m CW with 60w of drive. The specs say I should be able to get
1000w out with 40-60W
of drive. Does anyone have any experience with this amp and do I have a
problem somewhere?
I'm also using the 120v setting. I would like to use the 240v setting but
the jumper block on the back
doesn't match the diagram in the manual. Mine has 6 terminals on it and the
diagram only shows 5.
Again, would anyone know how to wire this thing for 240v?? And finally,
does anyone have the
factory data sheet showing the initial tune/load setting for each band so I
have a starting point for
tuning it up?
Thanks for any help!!
73's
Doug - N7NM
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