WE 236G Handset/Audio issues/troubleshooting

[Famicoman]

I'm remotely helping a friend get a 236G in working order. It had previously been converted for home use and is staying that way for his needs. He's noting that the the audio coming from the receiver element is very weak and the audio going through the transmitting element seems distorted.

His first step in troubleshooting will be testing the elements with a battery or replacing them but the mouthpiece and earpiece covers won't budge. Are there any tricks for unscrewing the covers when they won't budge? Heat and a prayer?

Further, in the event that he replaces the elements and one or both of them doesn't work, what would the next steps in troubleshooting look like? This phone is older than what I normally deal with, but you can assume competence in following a wiring diagram and using a multimeter.

Appreciate any help!

[HarrySmith]

Most payphone handsets caps are glued on to prevent tampering. Some have had luck with heat or solvent but that does not usually work. Do you know if it ever worked properly? You could try rapping the end of the handset sharply. Sometimes the carbon gets clumped up inside the element and that might loosen it up.