[AMPS] Collins 204H-1/GRT-12 HF Amp (2x4CX1000 2-30 MHz)

[Lance Collister]

Hello Amplifier gurus!  I am interested in selling my HF amp to help
contribute toward the costs of my 6m EME antenna project.  I don't use HF anymore,
so I really can't seem to justify hanging onto it.  It is big, and would have to be
picked up by somebody in the Pacific Northwest.  It is approximately 22"W x 22"D x
5.5' high and weighs a few hundred pounds.  It does no longer have the auto tuning
circuitry in it.  It does not currently work, but I am fairly confident it only
requires a simple repair to restore either the bias or screen voltage.  A loose
screw fell down into the circuitry years ago and I haven't had the time, interest or
need to repair it.  I have a couple of manuals for it that come pretty close to
matching this unit's circuitry (although the part humbers referenced seem to be
different).

Just prior to its failure, I removed the driver stages from it and installed a 50
ohm load across the grids, so it could be driven directly with a 100w transceiver
without all the various attenuation pads that were previously required.  It worked
GREAT in this mode (until the missed loose part fell into the works - HI!).  (B+
supply is still all OK).

Needless to say, the amp runs plenty of power!  It was manufactured by "Republic
Electronic Industries", obviously subcontracting under Collins.  It has an HN
connector for output, and a built-in wattmeter.  Of course, I have never actually
put such a signal out on the air (!), but I have seen it very easily go up to 4 kw
PEP output.  It has no loading control, so requires either a really huge antenna
tuner or needs to be run into resonant antennas (which is what I did here, on 75m,
40m, and 20m). It runs anywhere between 2 and 30 MHz.  I think with the addition of
another mylar capacitor in the lowest bandswitch position, you could get it to go
down to 160 meters, which is where I really wanted to use it if I keep it. 

I also have a couple of spare 4CX1000A's I will include along with the amp, since I
don't need them for anything else.  I am asking $2000 for the amp AS-IS.  If I have
time to get it throwing flames again, it should be worth much more than that.  I
would appreciate hearing from anyone in the Pacific Northwest seriously interested. 
MNI TNX and VY 73, Lance

-- 
Lance Collister, W7GJ (ex: WN3GPL, WA3GPL, WA1JXN, WA1JXN/C6A, ZF2OC/ZF8)
P.O. Box 73
Frenchtown, MT  59834  USA
QTH: DN27UB
TEL: (406) 626-5728   FAX:(406) 728-6320
URL: http://www.bigskyspaces.com/w7gj

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