I had something strange happen today. A couple of weeks ago our club's C177RG suffered failure of the PS Engineering audio panel. PS Engineering was great, they gave me an RMA, I sent it to them and got it back in about a week, looking brand new. Cost ~$600 plus shipping to them. So today I go to put the refur audio panel back in the Cessna using a 3/32" driver, it worked fine, but when I selected the #2 KX-155 radio the audio panel did not key when the PTT was pressed. No sidetone, no 'tx' indication on the KX-155 display, and no radio output. Is there a problem with the new audio panel, or the #2 King radio? Well, our club has a Warrior that also has a KX-155. No problem I thought, I'll pull the Warrior's KX-155, plug in the Cessna's KX-155, and see if the Cessna radio works in this other airplane. Now comes my problem. This is a ~2 year panel in our Warrior, the KX-155 sits right below a GNS-650. So I put my 3/32" in driver into the tiny hole, and start to turn. In all other times I've done the radio begins to back out as soon as you start turning. Not today. I can turn this KX-155 release mechanism lock to lock and the radio does not move at all. I tried a bunch of times, the radio never move even a fraction of an inch. Is it possible that new panels use some other method of securing radios in light planes instrument panels, besides the 3/32" drive procedure? Or do I need to dig it out with a crowbar? I'm befuddled, and suggestions as to how to get this radio out would be appreciated.