[ICOM] Schematic and board layout for HM-14 needed

[D C (Mac) Macdonald]

I have a small schematic that came with the HM-14
when I bought it to go with IC-28H in early 80s.
However, I modified it to cut down the output because
it overdrove the  pants off the 28H.  I am now trying
to get it to work with 228H, 2400A, and 2710H and
don't seem to have enought DTMF output.  I figure
I must have made some other mod other than the 510
or 470 Ohm resistor directly across the electret
element.

Trying to reverse the mod(s), get one HM-14 to work
right with a 28H and the others to drive the other
remaining rigs properly.

The HM-14 was standard mic with 228A/H, but there
is no schematic or board print in the service or
owner manuals.  Same for owner/service books for
the 28A/H.

Thanks and 73,

Mac, K2GKK/5
Oklahoma City, OK

p.s. To all:

Finally getting rain in OKC, the first
measurable since October.


-- "Michael P. Olbrisch" <mike2004 at elp.rr.com> wrote:

From: "Michael P. Olbrisch" <mike2004 at elp.rr.com>
To: "'ICOM Reflector'" <icom at mailman.qth.net>
Subject: RE: [ICOM] Schematic and board layout for HM-14 needed
Date: Sat, 28 Jan 2006 16:10:32 -0000
 
Sorry Mac - I have NO data on the HM-14.

I didn't try it, but perhaps there is something
in the IC-900 or IC-901 service manuals?  I know
they can be downloaded someplace.

If you come up with something, can you point me
to it also?  With 4 of them, I suppose some day
I might need it.

Again, sorry.

Thanks.

Mike.  KD9KC
El Paso, Texas.