[Elecraft] Re: power-on current spike - FIXED!

Tue Jan 13 02:29:02 2004

Thanks to all those who helped me track this down, not the least of which
was the "most excellent" guys working for Elecraft under the thankless
title of Tech. Support.  When all was said and done, they helped me track
down a faulty LM2930T (8V power regulator) on the Control board.  They've
seen very few of these that were bad -- and it didn't really *look* very
bad on an oscilloscope -- but apparently I got one far enough out of spec.
to be causing my current spike and blowing fuses.

Anyway the folks at Elecraft sent me a quick replacement; I just finished
installing it, and re-'scoped it.  Spike is more in line with what one
would expect, and the power-up curves on the regulator look like they're
supposed to.

I'M IN BUSINESS!  And on the air just as soon as I can get the final
alignment, etc. finished.

73, from a very happy KD7WUR

----- Original Message ----- 
From: "Trent - KD7WUR" <[email protected]>
To: <[email protected]>
Sent: Sunday, January 04, 2004 15:25
Subject: K2: power-on current spike

Howdy All!

I'm building up my K2 (what a delight[*] this kit is) and have been having
problems with power-line fuses:

Once powered up and running in Stage 1 tests/alignment, the rig runs
0.06 -
0.10 A (depending on day/nite, dot/bar, etc. settings) which is exactly
what
the manual says to expect.

However, the 2A fast-blow fuse I had in the power line (directly fed from
a
hefty 12V gel-cell) blew IMMEDIATELY the first time I tried to power up.
I
put the system on a RIGRunner and put it on a 5A fuse ... this on lasted
most of the night (many power-ons/offs) before finally frying on a
power-up.
I've since put it on a 10A fuse to keep the fuse attrition rate down.
(The
RIGRunner uses standard blade-type automotive fuses.)

Over 5A draw -- even occasionally -- is disconcerting enough for me to ask
...

SHOULD a K2 be pulling so much current at power-up?

(Yes, I realize a lot of circuits are energizing and initializing, which
includes the power-on resetting all the relays, and such.)

TIA for any help/advice, etc.
73 de KD7WUR, Trent in UT

[ * Trent makes a valiant attempt to turn a blind eye to the painful
Errata
steps involving RFC15 -- otherwise a thoroughly enjoyable Christmas
gift! ]