Originally Posted by uniden278
Not terribly familiar with that exact model, but a lot of the older Motorola mobiles are set to defeat the PL when they are off the mic clip. Your radio may be programmed this way. If you have no way of reprogramming yourself, try hooking it up to a grounded (metal) Mic clip and see if the problem goes away.
That's pretty much correct, except the mic clip doesn't need to be grounded. However, the mic does need to be in the clip. The metal of the clip closes the circuit between the inner and outer sections of the mic hang up pin assembly and places the radio in an "on hook" condition. That enables Rx PL.
If working on the radio on the bench, either slide a spare mic clip onto the mic. I've been known to slip a small screwdriver blade in there if there's no mic clip nearby.