Hardware Hacking

Receive and Transmit Expansion for ICOM IC-707

1. Remove power and antenna
2. Remove screws and open case
3. Locate front unit board (The one behind the dial)
4. In Version 1: Locate and remove Diode D12

[] D12 [] D13
[] D11

Remove the top cover and locate the main PC board (it’s to the rear or
the
chassis and holds the speech option, see the operators manual). R516,
R517
and R518 is located in the right hand corner inside the small metal
can.
There will be 4 adjacent resistor positions with 2 positions populated
(R517 & R518)the top position is unknown. The small metal can is
located
on the right hand side of the main board. R455 is located below and to
the
left of J12 (the speech module connector). R455 is also unpopulated and
it’s to the left of R140.

If you can’t find a 603 size surface mounted resistor, carefully
unsolder
an exsisting resistor and re-populate it in another position. R455 can
be
replaced with a zero Ohm resistor by shorting the position with a fine
stran of wire that was taken from a ribbon cable.

After the modification, the radio will lose it’s memories and will
require
reprogramming.

Icom 207H Dual Band Mobil…..

remove the 4 screws ataching the bottom cover and remove the cover. (I had to
use a small screwdriver to pry on the cover. It’s made to fit tight)
with face toward you and belly up look to far right of board and close to you
locate a row of SMT diodes 3 on top then a shift to right and a few more.
The three are in a PERFECT row top to bottom! count from the top of the row
1 2 3. Remove the # 2 & 3 diodes. Now continue looking down from there and
you will see a resistor sticking up in the air (W14). Clip the lead off of
the resistor. Reassemble the radio and preform a CPU reset by holding the
Set and S.MW buttons while turning the radio on…(page 69 of manual).

You now will have :

118-135 RX (stock)
136-174 TX & RX
320-399 RX
400-479 TX & RX
849-950 RX

The Transmitter will work and transmit at ALL of the listed

This mod is easy to preform and takes about 10 minutes to accomplish.

For all those who wants a little more of driving power for
an old amp with the new IC-746,here is the way to do it
easily.
Important settings pots within the IC-746 HF/VHF radio.
Remove the twelve screws holding on the bottom cover. With
the Radio laying flat on it’s top remove the bottom cover.

Underneath the radio there is a board named MAIN UNIT
(B5083J) where there are 4 important small pots provided
to increase or decrease the power output in different
bands as follow:

R-989 HF Power output (rated at 100W)

R-991 50 Mhz band Power Output (rated at 100W)

R-993 144Mhz band Power Output (rated at 100W)

R-994 AM Power output (rated at 40W)

R-546 Tx gain,set at factory for best linearity in TX IF
(better not to play with it)

This is the mod for an IC-746 with the diodes in the 1, 2, 4, 6, 9 and 14
position and the description below explains this.

! IMPORTANT !

There seems to be new version of the diode pattern out there with diodes in
the 1, 3, 4, 6, 7, 10, 11, and 14 position and the mod DOES NOT work for
this pattern. If you find this pattern after reading the mod below, DO NOT
try it. It DOES NOT work. If I find the mod for that pattern I’ll try to
get it posted here also.

Remove the twelve screws holding on the bottom cover. With the Radio laying
flat on it’s top remove the bottom cover. Turn the radio so that the front
panel is to your left and the antenna connectors are to your right. Locate
the IC labeled “ICOM HD6433042SF”. About 3/4 of an inch to the right is a
vertical row of diodes. The left hand column of diodes has 7 diodes (14
possible spaces). The right hand row is full with 14 diodes. Remove the
diode in the 6th SPACE from the top in the left hand column. DO NOT remove
anything from the right hand column. This should get you TX from about
100KHZ to 60MHZ and 118MHZ to 176MHZ. Do this totally at your own risk.
Never, ever transmit out of the ham bands or your privileges..