[Elecraft] KX-1 dead :(

[Don Wilhelm]

Tod,

Somewhere between your power supply and the anode of D2, there is a problem.
It may be a high resistance in a connector or a burned PC board trace or a
relatively low resistance (but not zero) path to ground which is dragging
down the power supply output.  With the power source de-energized, check all
the connections and make a continuity check from the power supply positive
terminal all the way to the anode of D2 - you should find zero ohms, AND
(caps because it is often overlooked), check continuity from your power
supply negative terminal to the KX1 ground - this should also be zero.

If the continuity checks look good, then power it on and check the power
supply voltage right at the power supply output.  If it is the same as the
voltage to ground that you read at D2 anode, then you can blame the power
supply itself rather than the KX1, but if you have full power supply output
at the supply terminals and something different at the anode of D2, make the
continuity and connector checks again - these points should be connected and
as a result of that connection they should be at the same voltage.

73,
Don W3FPR


> -----Original Message-----
>
> I just completed the voltage checks on page 27 of the assembly manual
>
> Here's a comparison of the results when working versus now
>
> U1 pin 1 was 4.94v now 19.5mV
> U3 pin 6 was 6.05v now 2.47v
> D2 Anode was 14.83v now 2.7v
> D2 cathode was 13.75v now 2.5v
>
> Voltage measured at the supply is 12.3v (Astron AS-35)
>
> Tod
>