[ARC5] T-17-D Mic Question

[Mark K3MSB]

As reported a few months ago,  my trusty T-17 mic with replacement mic
element suffered an internal breakage, fortunately at the very end of the
Reading Air Show.

A very kind fellow sent me a box of old carbon mics, one of which was a
T-17-D.   He said the audio was very low, and indeed it was.

Today, just for fun, I disassembled the mic element. Some of the carbon
grains were indeed clumping.  I removed the grains and put them under a 60W
lamp for several hours.

[image: image.png]

I reassembled the mic and the audio is better, but still low.   I had no
idea how to put the grains back in, so I just filled the little bowl (top
in the above picture).

One half of the T-17 mic (that has the busted internal part) can easily be
removed via 3 screws.

The T-77-D that I worked on today has only two screws at the base of the
handle, on opposite sides of the mic.   I can see no way to access the
inside of the mic, unless you remove those two screws and yank the two
halves of the mic apart.... and I thought I'd check before I did any
yanking as the two halves appear to be bonded.

Have any of you done this?

Resistance has dropped from 50K or so to between 2K and 9K.  Still very
high than the several hundred ohms I'd like to see, but better than 50K.  I
think the varying resistance may be due to needed cleaning of the switch.


In any event, if I can get the shell open, this D variant will be seeing a
replacement mic element in its future.

73 Mark K3MSB
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