[Elecraft] KPA100 D1-D8 voltages
Ben Hofmann K1NT
benkb1ahr-elecraftlist at yahoo.com
Thu Jan 11 08:00:27 EST 2007
I've completed construction of my KPA100 and am doing
final voltage checks listed in the manual on p.46. My
KPA100 as bought was a rev. C kit, but prior to
construction I purchased parts to build it as a rev.
D. Apparently I was not thorough enough in annotating
my manual, as I was looking for the high voltage from
the bias supply at the cathode of D13, but in the rev.
D manual, the test point is changed to the junction of
C77 and R11. Before realizing this, I had the heat
sink removed and was testing voltage on D1-D8.
Although the voltage at junction of C77 and R11 was
within spec, many of the voltages at D1-D8 are
significantly different from the tables in the manual.
I don't know if I should be concerned about this or
not since the final high voltage is within spec (now
that I'm measuring at the right test point), as is the
negative supply for the RS-232. Here's a list of my
measurements at D1-D8.
Spec Mine
Diode Anode Cathode Anode Cathode
D1 32 130 21.1 138
D2 84 32 89.0 20.9
D3 21 84 18.1 88.7
D4 36 21 38.2 17.1
D5 24 36 15.9 38.2
D6 13.7 24 13.5 16.0
D7 -22 -8.8 -24.1 -1.1
D8 -8.8 0 -1.1 0
Any insight would be appreciated.
-Ben K1NT
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