[Elecraft] Re: K2 S/N 02676 Hi Current on tune

Sat Dec 14 11:47:01 2002

Hi

It would take a lot of current through D3 to make it smoke this diode is
rated at 1 amp at 1000 volts so it is unlikely any of the normal signals
could smoke it. I don't see how a bad Q2 could do it as it is limited by a
1K resistor. If D3 is really the smoked part then I would look for a solder
bridge to the 13.8 volt primary supply. That is the only supply that would
provide enough current to damage D3. The re-settable fuse is rated at 3 amps
but that is the hold current it may take 4 or 5 amps to trip it so the
primary supply could zap the diode before the fuse tripped if there is a
short somewhere.

Don Brown

----- Original Message -----
From: "Robert C. Abell" <[email protected]>
To: <[email protected]>; <[email protected]>
Sent: Saturday, December 14, 2002 12:24 AM
Subject: [Elecraft] Re: K2 S/N 02676 Hi Current on tune

> I have been discussing this problem for the last month with Scott but we
> together have still been unable to resolve it. Scott agreed with my
> suggestion to ask Gary to help resolve it. This unit is still under test
> following assembly.
> Last evening while testing I activated the TUNE mode and as usual with
> my rig I got a HI CURRENT indication on the display. This time the
> circuit breaker did not activate and I noticed a curl of smoke eminate
> from the rear center of the RF board. Further investigation revealed it
> came from diode D3 in the T-R switch cct.
> I have been unable to locate the reason, unfortunately. There are no
> obvious shorts and all diodes in this cct. are correctly oriented. Any
> help would be really appreciated. This is my 2nd. K2 assembly, no
> trouble the 1st. time.
> 73, Bob VE3XM
>
>
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