David Farber wrote:



** So no RF OR maybe the frequency is off.

Do you have a frequency counter that works at UHF ?

If so, use that to see if there is a carrier and at what frequency -
just hold the mic right next to a short antenna plugged into the
input.



The mute switch on the mic seems a little wonky. There is a lot
resistance (physical) moving it to the mute position and almost no
resistance moving it back to the "on" position. Does enabling the
mute switch turn off the RF?


** No, it just mutes the audio.

Last one of these beasts I saw had a problem with the frequency
synthesiser
inside the mic handle. It was outputting a carrier frequency the
receiver did not work on. Off by only 100kHz from one of the
available ones, but that was enough - plus the buttons on the mic did
nothing to change that frequency.

The local Shure agents supplied a new mic at trade price to my
customer, cos that had no way to fix it either.


I have a frequency counter... a Heathkit I built around 1982 I believe its
upper range is 30MHz.


** No use at all.


I was thinking if I could open up the transmitter,
maybe there was some minor physical damaged caused by some rough handling
around the mute switch area.

** The mute switch doe not stop RF.

Getting back to the disassembly question, can I
just unscrew the mic capsule? I don't want to force it but if it's ok to
safely remove it that way, then I'd like to get to the internal circuitry.


** The head should unscrew easily, then the C-clip as previously stated.

Be CAREFULL, the buttons that operate the switches are FRAGILE.

BTW:

Do you know the mic's frequency ??

The handbook gives tables for code letters and actual frequencies.

Do you have a radio scanner that covers the UHF band ??

You MUST have a counter or a radio scanner or you cannot service radio mics.



..... Phil