[Amps] Alpha 9500 problem

JTB jerryjtb at comcast.net
Sun Nov 25 17:13:46 EST 2018


Fellow Amp Aficionados,

Was looking for some new countries on CW during the weekend contest and
developed an Alpha 9500 amp issue. I was calling a fellow on 15 meter CW
with about  a KW output through an HF auto tuner to a matched Yagi (VSWR 1.2
). I looked at  my Power Master II wattmeter and noticed zero output. Looked
up at the amp and saw the Red LED gain flashing as I keyed the amp. A 1 was
present on the Green digital readout. Looking at the manual and checking all
the recommendations didn't fit my problem. All voltages were in the
acceptable level on the Alpha Remote control software. HV about 3800 checked
with Fluke VOM and HV probe. I can key the amp but nothing out. The FT-5K
SWR indicator flashed high SWR with 15 watts out to the keyed amp. I swapped
the 8877 tube out just to see if the heater had gone open reasoning the high
input SWR.  Same issue with  the new tube ! The heater in the removed tube
checked with a Fluke digital VOM. The issue is present on all bands. When
the amp is on standby the exciter's 10-15 watts is indicated on the
wattmeter with a flat SWR indicated. It looks to me that the amp is not
selecting and closing the tuned input relays. 

Has anyone else run into this problem? Where is the tuned input board
BCX_X430 board located in the amp?

Missing DX OUCH ! ! ! 

Jerry W0ZD/3





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