[Elecraft] Help Needed for KPA100 Amplifier

[Lyn Norstad]

Have you checked the voltage at the lower set of PowerPoles with the amp turned on?

I've seen issues with bad PowerPole connectors in the past.  Maybe something happened to them in the move.

73
Lyn, W0LEN


-----Original Message-----
From: elecraft-bounces at mailman.qth.net [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Carter Craigie
Sent: Thursday, August 12, 2021 11:43 AM
To: Elecraft List Members
Subject: [Elecraft] Help Needed for KPA100 Amplifier

 My problems all started when I moved my Elecraft KX3, PX3, and the ASTRON
RS-35A PS from the garage upstairs to the second floor. At first I noticed
that my Amp would put out only about 70-80 Watts. Then the output went
lower and lower until the Amp would not turn on. See below.

Here follows what I know at this stage:

The AWG 10 power cable from my ASTRON 35A PS to my Elecraft KPA100 amp is
about four feet long. At the terminals on the PS I measure 13.83 v and I
measure exactly the same at the cable’s end’s Anderson PowerPoles. (The
back of the amp accepts only Anderson PowerPoles.) There are two sets of
these PowerPoles, and the manual for the amp suggests using the lower set
for the Amp, and that’s what I have done. The manual recommends plugging in
the KX3 on the upper PowerPoles, and I have done that as well. And the
radio turns on, no matter whether the Amp is working or not.

To turn on the Amp I have to go to the Menu on the KX3, and rotate the knob
above the Menu button until I see “PA OFF.” Then I turn the main VFO knob
until the OFF changes to “ON.”

Some Indicator LEDs on the amp turn on:

ON (indicating the Amp has been turned on)
ANT 1 (indicating Antenna 1, the one I use to go to the antenna)
Mode MAN (indicating manual control—which I wish indicated Auto, for
automatic control)
FAULT (indicating SYS (I presume this stands for System) for which I could
find no helpful explanation in the manual).

After about 10 seconds the Amp turns off!

I need the Amp to turn on so that I can use the KPA100 Utility Program to
do any troubleshooting, but that is not possible, since the Amp will not
remain on for longer than those ten seconds I mentioned above.

Without the amp I can use my KX3 rig at up to 15W and can use the KP3
panadapter as well, so all is not lost! The harnessed set of cables
connecting the Amp, the KX3, and the KP3 all go through the Amp, and they
show they are doing their job of connecting the KX3 with the KP3. I just
had a very nice CW QSO with a station in Massachusetts and the reports were
599 both ways. Joy!

All of my cables are fairly well dressed, with no desktop clutter.

I don’t know what to do next.

Any suggestions or questions, please?

73,

Carter, N3AO
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