Elecraft KRX3 - Manual (Page 48)

A-1
Appendix A: Installing Crystal Filters in the KRX3 Subreceiver
The crystal (roofing) filters in the KRX3 subreceiver are contained in the L-shaped RF module mounted above the
main K3 RF board (see Figure A-4). Installing or changing the filters involves removing the RF module and the
circuit board inside. The filters plug into the circuit board and are held in place by screws. No soldering is
required.
If you plan to operate your K3 with the subreceiver RF module removed, see Removing the
KRX3 Module in the main text for information about replacing essential jumpers.
Tools Required
You will need a Phillips screwdriver and long nose pliers. Normally a No. 1 Phillips is correct, but some find a
No. 2 is a better fit. Always use the screwdriver that best fits the screws.
A grounded wrist strap and ESD dissipating mat are recommended whenever you work inside your K3.
If installed, your K144XV 2-meter Option Installation and Operation manual.
Procedure
If a screw seems very tight, try loosening the other screws first. Sometimes tightening
other screws during assembly causes one already in place to bind. Loosening the others will
usually free it.
Remove the K3 top cover as shown in Figure A-1. As you lift the cover off unplug the speaker wire
that connects to the KIO3 board in the left rear corner of the K3. If you have the K144XV 2-meter option
installed, slip the speaker wire under the chassis stiffener bar that runs across the top of the K3 along the
depression in the top of the K144XV module.
Figure A-1. Removing the Top Cover.