[Elecraft] dead k1

[Mike Morrow]

Mick wrote:

>diode D19 snipped and rig powered up into dummy load all seems

Mick,

I think a shorted D19 in your K1 illustrates why the DC power should be
fused.  Your D19 failure apparently pulled the 12 vdc supply down low, yet
did not cause enough current to flow to destroy reverse polarity diode D16,
or worse, destroy PCB traces.  You are lucky that you weren't using a higher
current supply.

For some reason, when a rig includes a series polarity protection diode, a
fuse in the power supply is often viewed as unnecessary.  Nothing could be
further from the truth.

Had some PCB traces been destoyed by high current flow though the shorted
component, tracing and correcting could be even more difficult with an
Elecraft rig than with other kit rigs since, for reasons which have never
been made clear, Elecraft does NOT provide figures in the manuals which show
the PCB traces.  This is a very, very serious omission in a kit rig manual.
It is a documentation fault has caused me considerable inconvenience when
troubleshooting or modifying my K1 in the past.

73,
Mike / KK5F