[Elecraft] Gary Surrency - Now: K1 RF-D19

[Mike Morrow]

Frank wrote:

>  Then I lost all power ... and heard a loud "pop"   A few e-mails
>  to Guru Gary, and TADA the culprit (D-19) was found...

The Zener diode (RF-D19 in the K1) that is often found across the emitter
and collector of the output transistor in most QRP rigs is a component that
commonly fails if you transmit for more than a few moments into a grossly
mis-matched high impedance or open load.  That results in a high voltage
developing that exceeds the voltage rating of the Zener (usually around 36
volts), destroying the Zener but perhaps saving the output transistor.

That failure willl also cause high current flow on the DC supply to the rig,
which is another good reason why the K1 DC power cord should definitely have
a fuse of about 2 amps rating in it, even though that's not mentioned in the
manual.

73,
Mike / KK5F