>I recently purchased one of these amps and just brought it home yesterday.
>This morning when I took it out to the ham shack, it slipped out of my hand
>and dropped onto the operating table. Everything seemed physically intact
>but when I try to load the amp with about fifty watts drive the plate cap
>starts to arc. I don't know yet but may need to replace the cap or other
>parts.
If the Tune capacitor's plates are not bent from being dropped, the
arcing may be due to an intermittent instability problem around 100MHz.
You can check this out by placing a wavemeter near the Tune C. To find
out where to set the wavemeter, pull the mains plug, couple a dipmeter
the the hv dc blocking C. You should find a sharp dip. Read the freq.
and set the wavemeter accordingly. If and when the Tune C arcs, you
should see a large indication on the wavemeter. // Another way to check
this out is with a vhf field strength meter/spike ant. like you would
use to check out a 2m handytalky. If the vhf FS meter pegs out when the
Tune C arcs, chances are you have a vhf oscillation present.
>does anyone on this list know where I can locate parts for it?
Maybe you don't need replacement parts. Maybe you need lower vhf Q
parasite suppressors, Kevin?. Doing so would reduce the vhf
amplification at the anode circuit resonance by about one half.
- later -
cheers
Rich...
R. L. Measures, 805-386-3734, AG6K
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