How difficult is it to replace the PTT button on a '93 MXT. It has the later model yoke.

Pop it up out of the yoke and you will see; you'll need a soldering iron and a replacement switch.

The hardest part can be the length of the two wires going through the yoke. If they're too short, you can't get the PTT switch out far enough to do a good solder job. If you get a chance to replace short wires, do it. Use the Maule PTT switch rather than some off-brand. It's got a larger button that's easier on your thumb and it will last longer than a cheap version.