Greetings,

I have an older, used, "patent pending," Shure 545S Series 2 (pistol grip) microphone, and I'm gradually fixing it, having first reassembled the switch in the handle section.  I do get sound from the mic, but it is a little on the quiet, "hollow," and less low-frequency side.  I'm using it as high-impedance.

• I've been trying to gently unscrew the top black plastic capsule section to see if the leads there may need to be re-soldered to the capsule; however, it is very tight and doesn't budge at all. 
• The top grill area that normally spins freely on most Unidyne III models is tight, as well. 
• Where the back cover to this model normally is, it is open, showing the wiring that emerges from a small hole in a yellowish-waxy looking substance and then goes down the tension spring into the switch area of the mounting "pistol grip" handle. 

Now for a lot of 'wondering'.... :)
I'm wondering if a previous owner or repairman did some gluing in these areas, or if it's just age that has made them really tight.  Seeing as this is one of the older "patent pending" ones that has a chrome name ring, rather than just silver (around the grill area), I wonder if conventions of assembly were a little different at that time, maybe partly to protect the patent until it was secure (through usage of glue on the threaded areas and waxy stuff in the circuit area)?

What would be a good method for loosening that really tight capsule section?  I had thought about tiny amounts of acetone down in the threads, in the event that there is some superglue, etc down in there.  I had thought of a heat gun, very lightly used, but was wary of damaging the capsule/diaphragm.

Thanks for any leads!