Elecraft K2 Keying Modification Instructions - Manual (Page 3)

3
Changes required to the K2 Control Board
On the top (component) side of the Control board, CAREFULLY cut the PC board land running
from RP2 pin 2 to U10 pin 3. This land runs under U10, around U10 pin 2, to pin 3. Cut it at the
point indicated in the illustration, above.
Use an ohmmeter between RP2 pin2 and U10 pin 3 to confirm that the connection between these
two pins has been completely broken. Resistance should be greater than 1k ohms.
Remove D3 and replace with an 82k (Gry-Red-Org) 1/4w resistor. See illustration, above. Note that
the new resistor at D3 will now be designated as R22.
Remove R21and replace with a 270k (Red-Vio-Yel) 1/4w resistor. See illustration, above.
Remove C31 and replace with a .01µF ("103") monolithic capacitor. See illustration, above.
Locate the 4" (10 cm) piece of green insulated wire that was provided with the modification parts
kit. Strip 1/4" (6.4 mm) of insulation from one end of the wire and then remove and discard the wire
from the remaining insulation. RETAIN the green insulation.
Cut two 1/4" (6.4 mm) lengths of the green insulation and slip them over the leads of the remaining
uninstalled .01 µf ("103") monolithic capacitor (C46).
WARNING
Components on Control Board can be damaged by Electrostatic Discharge (ESD)! Be
sure to take precautions to protect against ESD by using a grounded wrist strap or by
touching a grounded object periodically while working with the Control Board.