[Milsurplus] T17 microphoone repair?

[WA5CAB at cs.com]

Dean,

By "dry them" I assume you probably mean putting them in an oven.  I can't 
think of anything that will accomplish that just keeping the mics in an air 
conditioned space wouldn't accomplish.  

The three most common problems with T-17's are bad cords, bad switch contacts 
and bad connections between the microphone element and the center and side 
spring contacts.  Remove the microphone's side cover and check continuity from 
tip, ring and sleeve of the PL-68 to the ends of the wires inside the handle.  
Remove the plastic sleeve from the PL-68 and inspect the wires inside the 
plug.  

Then check continuity across both of the NO switch contacts.  Should be open 
with PTT button released and zero ohms when closed.  Burnish contacts to fix.  


Check continuity from the microphone element's switch contact to the common 
wire (the one going to the PL-68 Sleeve.  Should be something like a few dozen 
ohms, and vary when you shake the mic or whistle into it.  If open, remove 
black plastic cover, remove element and check continuity across element itself.  
Clean the center and side contacts and check continuity from the center 
contact in the mic head back to the switch contact.  Also check continuity from the 
side contact to the common (sleeve) wire.

If everything checks OK except the element, you can try tapping its rim in 
several spots against the workbench top.  If that doesn't "fix" it, unless 
someone else knows another trick, you'll have to replace the element.

In a message dated 7/14/2005 10:10:51 AM Central Daylight Time, 
kelloggd at uthscsa.edu writes: 
> I have some T17 microphones that I hope to restore to working 
> condition.  2 of them will trip the dynos when the buton is pushed 
> but will not send voice.  I have been told that I should dry them and 
> then shake them around to loosen the carbon granules.  Does that 
> sound correct?

Robert Downs - Houston
<http://www.wa5cab.com> (Web Store)
MVPA 9480
<wa5cab at cs.com> (Primary email)
<wa5cab at houston.rr.com> (Backup email)