I'd previously posted how I discovered the nasty hum problem we had
at N4N on 80m and sometimes on 15m was caused by the failure of three
out of five 4700 uF capacitors in the unregulated part of my 12V
supply -- a 25A CB-style supply from 1989.
I got my shipment from Mouser today and replaced all five caps with
new units. I also added three extra caps to the backside of the
board. This makes for eight 4700 uF capacitors or 37600 uF.
I also replaced the regulated side capacitor, a 2200 uF unit with a
4700 uF cap.
From my tests, I can pull 20 amps at 12 volts, and the supply only
has 1-2% ripple, tops. The K2/100 typically draws 16 amps at full
output, although it wants a bit more on 80m and 160m.
Bill Coleman, AA4LR, PP-ASEL Mail: aa4lr at arrl.net
Quote: "Not within a thousand years will man ever fly!"
-- Wilbur Wright, 1901
|