[Elecraft] Chirp with K2/XV222 - Fuseholder Issues

[Ron D'Eau Claire]

When I built my KPA100 back in 2003 my kit was short part of the fuse holder
so I went down to the automotive store and bought one. A few months later my
K2/100 started shutting off unexpectedly while transmitting. I discovered
that the fuse holder was warm enough that the plastic was softening
slightly, allowing it to stretch so the spring loaded contacts no longer
pressed hard enough against the fuse! The lighter the contact, the more the
resistance, the more the resistance the more the holder stretched under the
spring pressure.

I had long since received the axial fuse holder Elecraft uses and installed
it. I've not had an issue since. I assumed the holders Elecraft sourced used
a more robust plastic. However, if that ever happens again, I'll switch to
the blade-type automotive fuses.  As you noted, their contacts are larger
and should have much lower resistance. Also, the electrical contact pressure
doesn't depend upon the molded plastic like axial type holders do.

I think there's a reason we don't see axial type fuses in automobiles any
longer and I sure don't experience fuse holder failures in my car! 

73, Ron AC7AC


-----Original Message-----

It looks like one of the causes of my chirp on 222 MHz with the K2/XV222
combo was an unreliable fuseholder (an in-line type for an AGC/3AG/1-1/4x1/4
inch fuse).  I wonder if automotive blade type fuses/holders might be more
reliable as far as contact resistance goes.  Does anyone have any good
knowledge on this ?
 
73,
Steve VE3SMA