[Elecraft] KPA-100 PS

[Doug Faunt N6TQS +1-510-655-8604]

   From: "Don Brown" <DolfinDon@msn.com>
   Date: Sun, 14 Mar 2004 10:40:04 -0600

   Hi

   I have had good luck with the MFJ-4125 and 4225. The 4125 is a
   basic switcher rated at 25 amps with no meters. The 4225 is the
   same with lighted volt and current meters, a front panel voltage
   adjust and a cigarette lighter type socket in addition to the 5 way
   binding posts. I have not had any problem with switcher RF from the
   power supplies. The 4125 has a quieter fan and is very small about
   the same size as the K1. I also have a Astron SS-25M that works
   well but is bigger and has a louder fan.

This is a good place to bring up what I found in my MFJ-4125 after it
failed for the third time.  The negative connection to the PC board
was made by a ground lug on TOP of the single sided board, and the
actual trace is on the bottom.  This means that the screw was carrying
the full current.  In the tough environment I was using it (RTTY
contesting and DXpeditioning, with 100W ICOM radios), the screw would
loosen, heat up and eventually the board charred, and the connection
was lost.  The third time, I got tired of sending it to MFJ, found
this, and replaced the existing connection with a thick wire actually
soldered to the trace (the hole is there already).  I believe that
this will fix the problem, but the 4 hour RTTY Sprint on Saturday
wasn't really enough of a test.  So, if you want a more reliable 4125,
you might want to take a look at those connections.

Note, the Samlex 1223 weighs almost the same as the 4125, and is just
a little larger.  It's been proven reliable on several DXpeditions by
many people, and now comes with a probably better connector (the same
type that Astron is using now).

I've used a 4225 in the same environment, with no problems, but it's
larger.  The extra features are useful, though.  

73, doug