Notes on Elecraft K3 (5) SN 4829

June 2019

Donated from the estate of Fred Cady, KE7X, secured for CCC by KB7Q.

Includes sub-receiver, DVR, updated KIO3B and KXV3B boards. Has original synthesizer board.

May 2022

WI9WI reports only 10 watts output. Probably bad pins on the PA board. Jim brought it back to the States. N7IR says it will probably have to go to Elecraft, and it will take many months.

9 July 2022

K3 arrived at N7IR for evaluation.

25 July 2022

Repaired by N7IR.

When I checked this K3 I found that the low power amplifier (LPA) would only put out 2.5 Watts, independent of the setting of the PWR control.  Further testing revealed that both output devices on the LPA were inoperative.  The root cause of the failure was an overheated surface-mount resistor in the 100 Watt amplifier feedback circuit.  It had gotten so hot that the solder melted on one terminal and the resistor popped into a vertical position.  This is known in the trade as "tomb-stoning".  I learned a new phrase.  Fortunately neither output transistor in the 100 Watt amplifier was damaged.

I replaced both failed transistors in the LPA and put gate protection diodes on the new ones.  I updated the feedback network resistors in the 100 Watt amplifier with the values and types specified by Keith, the Elecraft K3 repair tech.  I have one more pair of LPA output transistors and a reasonable stock of the resistors needed to update the 100 Watt amp.  I calibrated the 5 and 50 Watt amplifier transmit gain and all is now well with SN 4829.

Late August 2022

Shipped to NN3W for October transportation to Curacao.

October 2023

Returned to Curacao by NN3W.