[Elecraft] Changing defective KX3 VFO B encoder

[Lyle Johnson]

Scott,

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.

73,

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.