[K3] switched DC output jack- simple mod.

[Bruce Beford-2]

Re: Having the DC out accessory jack output current measured by the K3.

 

Well, I looked at the schematic and determined that this would (in theory)
be a simple mod. Page 5 of the schematics (page 3 of 4 Iof the K3 RF board)
shows the DC power control/measurement portion of the K3. The DC out jack is
fed via a 1N4007 diode, D34 after the power control FET, but before the
current is measured. The current drain of the K3 is determined by measuring
the voltage drop across a 0.05 ohm series resistor. It was a simple matter
to locate D34 on the bottom of the RF board (the rear bottom cover must be
removed). A trace to D34's anode was cut, and the anode then jumped to the
output of the resistor R36. It took all of 10 minutes, start to finish. The
ammeter on my K3 now includes any current draw from an accessory plugged
into the rear DC out jack. (My P3 is adding about 250 mA at a screen
brightness of 30).

 

I love it when a plan comes together.

 

Bruce, N1RX

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