9/13/97

I received the following Icom IC-970 9600 baud FSK Mod directly from ICOM.
It was accompanied with a diagram for using an AEA DSP-2232 between an
IC-970 and IC-728 for switching. If anyone is interested in this diagram
please request it from ICOM tech support.

The following is verbatim what was printed on the sheet from Icom. It was
submitted to them by someone but no name appears on the sheet.
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The following describes mods for 9600 baud FSK for an Icom IC-970. The
mods require NO soldering or cutting on the IC-970, and are thus easily
reversible.

Icom suggested mods for 9600 were:

- TX mod input at collector of Q59 on the main unit.
- RX Main at DET output in J29 (main unit).
- RX Sub at TSAOS output in J9 (main unit).

I made slight mods to Icom's mods:

- TX mod input at collector of Q59 on the main unit. This is available at the
  top of R51 with a micro clip. Ground is at the top of R60 with a micro clip.
  These resistors are about 3" back from the front of the Main unit and 2"
  from the right. The micro clips were attached to a length of RG-174 mini
  coax. No mods to board! The leads of the resistors appear to be painted.
  Scrape the paint off with a small, sharp knife (a small mod).

- RX Main output at TSAOM at J29 (main unit). Available on P85 (tone
  squelch option socket) under the top cover.

- RX Sub output at TSAOS at J9 (main unit). Available on P87 (tone
  squelch option socket) under the top cover.

Two lengths of RG-174 mini coax were connected to a 6-pin headers with the
center conductor on pin 4 and ground on pin 3. The headers were covered
with heat-shrink tubing. The headers plug into P85 (MAIN) and P87 (SUB).
The three coax cables were routed to the back-right of the IC-970 case. The
two TVJ hold covers were removed and replaced by two dual RCA jack
boards. These boards were attached with a small bolt through the hole for the
TVJ screws. The coax was attached to three of these jacks.
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This is the end of the mods that I received from ICOM.

Bruce Paige, KB5ZRV                       Packet KB5ZRV@F6CNB
AMSAT Area Coordinator, Houston           Internet  KB5ZRV@AMSAT.ORG