[Amps] Alpha 89 question

[Rob & Terri Sherwood <rob@sherweng.com>]

I may have a keying / PIN diode switch problem with my Alpha 89.  There 
are key down make and key up break noises (pop or click) that did not 
exist before.  Can anyone confirm whether the following observations are 
normal?

Setup:  Rig in CW mode, set for minimum drive / output power.
RF cable from rig to input of Alpha 89 disconnected (no drive to amp).
(If concerned about no load on rig, hook it to a dummy load.)
Amp connected to antenna or dummy load, does not matter.
Amp keying line from rig to Alpha connected (normal setup).
Amp in SSB mode (ssb bias). 
Key down, static conditions, 1 grid metering LED lit.
Key down, static conditions, 1 plate metering LED lit.
On key down make, 2nd plate LED lights briefly.
On key up break, 8 plate current LEDs light briefly (600 mA reading).
(Amp can be in CW bias mode, and the 8 LED key up break spike 
identically occurs.)

With the rig coax hooked up normally to the amp input, the following 
occurs.
When the rig releases the keying line on the Alpha, the 600 mA spike 
occurs and I get a loud pop in the receiver.
I do not see a similar key break spike on my Alpha 99.
On a rig like the Orion, where almost any parameter can be adjusted, the 
amp key line can be delayed far after the RF drive quits on key up.  In 
this case, the pop in the receiver clearly occurs when the amp key line 
is released, not when the RF quits. 

73, Rob Sherwood
NC0B
303-722-2257






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