Bulletin:  KW7420
Vendor:    Kenwood / TM-742
Subject:   EXTENDED TX & 800Mhz

The following are instructions for modifying the Kenwood TM-742/942 for
beyond MARS/CAP TX/RX.  I accept no responsibility for the accuracy,
use, or performance of this modification.  Use at your own risk.
However, it worked fine on my radio and came from the best of sources.
It assumes a US market unit.

1.  Remove the front (display) panel from the main chassis.

2.  Remove the bottom cover of the radio (remove four screws on bottom,
loosen two screws on either side of unit).

3.  Place the radio bottom-up, with the front panel area facing you.
Observe the large green PC board at the front.  At the right end of the
board, about midway between the top and bottom of the board, observe two
rows of tiny serface mount resistors, each marked "473".  There will be
two rows of four resistors.  In the first row, the four resistors will
all be in the lower position, nearest the front of the radio.  In the
second row, the four resistors will be in the higher position, towards
the back of the radio.  See resistor matrix in Figure 1.

- - - -   + + + +
+ + + +   - - - -

Figure 1.  "+" means there is a
resistor in this position.  "-"
means there is no resistor in this
position.

4.  Desolder the appropriate resistors and resolder in the following
configuration:
    a.  First row (lower row), fourth resistor from left, move to the
open position in the upper row just above the current position.
    b.  Second row (upper row), third and fourth resistors from the
left, move each to the corresponding open positions in the lower row.
See Figure 2 for resulting matrix.


- - - +   + + - -
+ + + -   - - + +

Figure 2.  This is how the matrix
should look after the modification
procedure.

5.  Reinstall the bottom cover and reattach the display panel.

6.  Reset the microprocessor by pressing and holding the MR key while
the radio is powered on.  Note that this will erase all memories and
VFO's in each band.

7.  Theoretical frequency range after modification (not all radios will
be able to tune the entire range):

28 Mhz Band   RX:  18.0 thru 54.0
              TX:  26.0 thru 45.0

50 Mhz Band   RX:  40.0 thru 90.0
              TX:  46.0 thru 76.0

144 Mhz Band  TX:  136.0 thru 174.0

220 Mhz Band  RX:  215.0 thru 260.0
              TX:  215.0 thru 235.0

440 Mhz Band  TX:  410.0 thru 470.0

1.2 Ghz Band  TX:  1100.0 thru 1400.0


To access the "back" 100 memory channels:

1.  Press & hold the F key, the press the REV key.
The channels will be numbered A1 thru AA.  Repeat step 1 to
revert to the normal memory channels.



TM-741A/E 742A/E 800 MHz BAND RECEPTION WITH 440 MHZ UNIT

Band Change
-----------
To change to the 800 MHz band, select the 440 MHz band, then press
and hold down the [MHz] key for at least a second. Now 850.000
(initial setting) is displayed.

To return to the 440 MHz band, press the [MHz] key again for at
least a second.