Chuck Carlson, KD6RSQ wrote:
I have a Motorola GM300 that will not turn off the radio with the
power/volume knob even with the 16 pin assy. plug removed. Any hints?
Thanks
Chuck





http://www.batlabs.com/maxrad.html#power

This section has some information on a problem opposite of what you have
but it may lead you to a point in the radio where you can diagnose where
the problem is.