The VFO B encoder in my KX3 is defective. I've decided that I'd to try
and change it myself. My question is has anyone removed rubber button
membrane/pad from the circuit board. I believe there is a Mylar sheet
under the buttons, and it the button membrane seems to be adhered to the
the PCB. Is the button pad removable without damage to it or the Mylar
There is no need to remove the membrane switch assembly to replace the
encoder at the VFO B location on the KX3. I just examined a CP board
assembly to verify this.
However, a lot of heat (not high temperature! they aren't the same!) is
needed to unsolder the frame mounting lugs.
My approach would be to melt a small amount of ChipQuik on the 5 pins as
well as the two lugs using a soldering iron set too a temperature too
low low to melt regular solder, ensuring the ChipQuik has blended with
the solder. Might need a bit more at those pesky lugs.
Then use a hot-air gun to warm those pads simultaneously. The VFO B
encoder should then easily come off the board without damaging or
loosening any other parts.
I would be very hesitant to do this without using ChipQuik or its
equivalent to lower to melting point temperature at those seven
connection points. Repairing a heat-damaged PCB can be quite expensive.
Lyle KK7P (who designed this particular board in the KX3 product)
On 7/21/18 3:06 PM, Scott Manthe wrote:
> The VFO B encoder in my KX3 is defective. I've decided that I'd to try
> and change it myself. My question is has anyone removed rubber button
> membrane/pad from the circuit board.