TH78A.8

(Updated 11/24/92)
Mods for Kenwood TH-78A HT:

There are three (known to me) mods for the TH-78A HT.
1) Cross-band repeat
2) MARS
3) Beyond MARS

I have tried all three on my TH-78A and they work for me.  That doesn't
necessarily mean they will work for you.  Working with surface-mount
components without the proper equipment is hazardous at best.

All three mods require removal of the back cover and CPU shield.  This is
the procedure:

A) Remove three long screws from back cover.  You don't have to remove the
   belt clip.
B) Remove one short (machine) screw from below the antenna connector on the
   PTT switch side of the radio.
C) Make sure the battery is ejected and poke your finger up through the
   battery compartment and push the back cover away from the radio.  Tilt
   the bottom of the back cover away and up to remove it from the 
   chassis.  CAUTION: There is a ribbon cable connecting the chassis to
   the back cover.  Also, there are two very small o-rings around the
   LEDs on the top of the chassis that need to be kept track of.
D) Lay the chassis face down and the back cover component side up on something
   soft.  The two will still remain connected by the ribbon cable.  Orient
   the chassis so the PTT switch is toward you. 
E) On the chassis locate a brass shield.  It is the RF shield for the CPU.
   Desolder the shield on all four corners.  CAUTION: The shield is double-
   back taped to the CPU also.  Remove the shield.

The following mods require removal of one or more chip diodes.  The diodes
are located below the CPU (toward you if you oriented the chassis as 
instructed earlier) in a horizontal row.  There are six diodes and we'll
label them D1 through D6 going from RIGHT to LEFT.  Again, RIGHT to LEFT.
The leftmost diode is D6 while the rightmost diode is D1.  The only reason
we are labelling them this way is because that's what Kenwood does.

CONTINUED IN TH78A.9