[Elecraft] K2: power-on current spike

Sun Jan 4 19:56:00 2004

Thanks to those who responded (incl. Tom, Don, and Jim).

I'm in the middle of phase 2 build-out, so I can't do powered-on tests just
at the moment, but I've double checked everything mentioned (shorted power
connector, reversed relay, diodes, electrolytic caps, etc.), and I am
scouring the board for solder bridges.

I doubt it's any of the major parts (reversed diodes and the like) or it
would be a *continuous* problem (read "exhibited during normal operation,
not just power-on").  It *could* be something relay-related since those are
energized during the power-on reset sequence.

Mostly I wanted to verify that there is NOT supposed to be a "high" current
*spike* at power-on (where 4 - 5 A wouldn't necessarily be considered "high"
for a commercial rig, but certainly appears to be for this frugal little
beast <g>).

Still looking (hoping, hoping, hoping it's not a hair-line etching glitch,
which're murder to find)

t.

----- Original Message ----- 
From: Don Brown
To: [email protected] ; Trent - KD7WUR
Sent: Sunday, January 04, 2004 16:17
Subject: Re: [Elecraft] K2: power-on current spike

Hi

The K2 should only draw 200 to 300 mA depending on the options even at
startup. If you are at stage 1 then there are not any options and most of
the RF board is not installed so it looks like you have a problem if you are
blowing a 2 amp or larger fuse. Check the power plug you may have a short in
the power connector that connects to the power supply. Also check all of the
relays to make sure you did not install one or more backwards.

Don Brown
KD5NDB

----- Original Message ----- 
From: Trent - KD7WUR
To: [email protected]
Sent: Sunday, January 04, 2004 4:25 PM
Subject: [Elecraft] 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! ]

_______________________________________________
Elecraft mailing list: [email protected]
You must be subscribed to post to the list.
To subscribe or unsubscribe see:
http://mailman.qth.net/mailman/listinfo/elecraft
Elecraft Web Page: http://www.elecraft.com
Also see: http://www.elecraft.com/elecraft_list_guidelines.htm