[ICOM] IC2100 no transmit

[HENRY PFIZENMAYER]

My Grandson has a IC2100 a couple years old that he blew something in the
mic /ptt circuitry playing with his packet modem.

Interestingly , I can use my HM133S mike off a 2100H that is just a few
weeks old , and the old 2100 works fine  EXCEPT the HM133S mike starts
getting hot on the back pretty quick so I stopped messing with it.

The thing that really mystifies me is that his old mike works OK on my newer
2100H - but will not ptt his 2100 .
I downloaded a schematic and it looks like possibly he could have shorted
the pass transistor in the 8 volt regulated line to the mic - have not
checked that yet - but why his old  mike will work on the new 2100 and not
on the old one still is weird.

I do not see any identification numbers on the old mike so cannot tell you
the model - but its narrower than the HM133S.
I did swap cables and that did not make any difference.

Anyone see what I am missing ??? I hope
its not bone stupid !!!!

Thanks -- Hank K7HP