TM721A.13

MODIFICATION PROCEDURE

1. Turn the radio on and write down all of your memory channel
frequency assignments, PL codes and anything else you have in memory -
It will all have to be reprogrammed after the mod.  After writing down
all of your data, turn off the unit and disconnect it from the antenna
and power supply.

2. Next, remove the bottom cover on the unit.  Note: this radio
contains a number of CMOS parts which could be damaged by static
discharge.  Take all of the regular precautions to make sure that you
and your tools are properly grounded for anti-static work.  Note that
there is a hole in the rear of the subchassis which supports the
controller circuit board in which you can see a small, black, 1/4 watt
resistor which is labeled on the board as R57.  Using a small pair of
sharp cutters, clip the lead on the end of the resistor.  It is not
necessary to remove the part, just clip one end and bend it slightly
out of the way.

2. Next, remove the top cover and then open the front panel assembly
into the service position.  To do this, remove the four silver screws,
one on the top, one on the bottom, and one from each side.  Two of the
screws are in slotted holes.  Loosen the screws in the slotted holes
slightly so as to allow the front panel to be pulled out and swung down
in a hinge-like fashion.  Once open, set the radio on a table with the
hinged front panel hanging over the edge of your workbench.
Familiarize yourself with the inside of this compartment.  The most
notable features are a silver, button type lithium battery to the left
of center and a large, multi-pin microprocessor chip on the right.  DO
NOT DISCONNECT ANY OF THE RIBBON CABLES.

3. Locate the lithium battery and to it's left you will notice a row of
five programming resistor positions, with the middle position vacant.
The arrangement looks something like this:

|
|                        ____                    ______
|       I I:II          (Bat-)                   |MPU |
|                       (tery)                   |    |
|                        ----                    ------
|
|                  I <- R121 (remove for cross-band repeater operation)
______________________________________________

        VVV front of rig VVV

The (:) above indicates where a jumper is to be placed.  Use care in
soldering since everything is quite small.
CONTINUED IN TM721A.14