[Elecraft] A fluke may have fried my KX3 and KXPA100 I need advice

[Raymer, Timothy]

Now that you know it is the Power Supply, a couple of things to check.

Unplug it and let it clear out the cob webs.  There are some fault
protection modes that only clear with removing power and letting things
discharge.  Specifically, the crowbar circuit may not "uncrowbar" until
everything is discharged.

Second, you may have to do surgery.  I have replaced transistors and LM723
chips before.  

The resource that Andy, K3WYC, posted is invaluable for getting your power
supply back to the land of the living.

Good luck.
Tim Raymer
73 de KA0OUV


-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of n7tb at comcast.net
Sent: Thursday, May 21, 2020 22:46
To: elecraft at mailman.qth.net
Subject: [Elecraft] A fluke may have fried my KX3 and KXPA100 I need advice

I power my KXPA100 with an old reliable Astron RS35A power supply that I
have used for years.  I have it up on a 3/8 in spacer above the carpet to
keep it a bit cooler.

I power my KX3 from the back of the KXPA100.  I had the amp and KX3 on when
a loose usb cable that was normally connected between my computer and my
Signalink, had been disconnected to connect the signalink to my Raspberry
Pi.  While the USB cable connected to the computer was loose, it curled
around I accidently kicked it and it slid under the power supply and
contacted one of nuts on the bottom of the power supply and sparked.  My KX3
stayed on for a few seconds, then shut off.  When I tried to power it up
again, it stayed on for about a second or so, then powered off.

I checked the Astron power supply and it continues to put out 14.5V. I
connected it back to one of the two Anderson PP connectors on the KXPA100
and there are no led's lighting up when the KXPA100 is on.  I put a volt
meter to the other Anderson Power Pole at the back of the KXPA100 and it is
showing 4.6 v. output, not the normal 12 + V.

I connected the 14.5 v. supply directly to the KX3 and it behaves the same;
stays on for a second or so, then powers off.

So, it appears that usb cable that found it's way under my power supply, has
done some kind of damage to both my KXPA100 and KX3.

I know there is no service currently at Elecraft, and when service resumes,
it may be months before I can get the equipment repaired.  To say I am
frustrated would be a gross understatement.  I can use my K2 and KX2, but
both will be QRP.

I am turning to the group to get any advice you might have at this point.

Thanks so much!

73,

Terry, N7TB