K2 Excessive Current

[m1bnw]

To Jim K4ZM, Don W3FPR, Rolf  0H6KXL & Martin Renardy,

Thanks for all your advice on my excessive current consumption on my K2.
I did eventually find that I had a fault on the Control board in the 8 V Switching circuitry. The FET Q3 had failed and was turning on the 8 volt supply via Q1 to the Transmit side of the circuitry at the same time that the 8 volt to the Receive side was on. I think I saw a tiny wisp of a wire lodged in between the legs of the FET Q3 on the component side of the board. It looked like the Gate of the FET had been grounded to the Source.
After replacing the FET the current dropped back to 200 mA which is what you all suggest it should be and the TX 8 volt supply was turned off.
I'm not sure where the excess current was going in the fault condition but it is normal now.
It seems that you can't examine your work enough before powering up.

Regards Colin
m1bnw
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[Stuart Rohre]

In today's ever more crowded circuits; I find that during installation of a
component, I should either hold the end of the wire to be cut or put a
finger on it, so that it will not "fly" into some part of the circuit and
short something.  It is safer than nipping ends of wires with the cutters
without thought to a wire bit flying into the eye, or hand, or as in this
case, between two leads of an active component.

At the end of construction, it is good to hold the board upside down and end
down and tap it to dislodge any stray bits of wire.

-Stuart
K5KVH



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