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DOUBLE THE MEMORY CHANNELS OF THE ICOM R BY
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DOUBLE THE MEMORY CHANNELS OF THE ICOM R7000 BY
REPLACING THE SPEECH SWITCH
by Jean-Louis Ecochard
I Introduction
This modification is based on information received both
from Bob Parnass and from Gary on the ICOM Technical
Support line.
Although simple, this modification is rather delicate
to implement because it requires knowledge of unsolder-
ing and soldering CMOS components. It also involves
removing the speech switch. This will of course void
any ICOM warranty and the result may be a very expen-
sive paper weight. It is very important to note that
some vendors of ICOM equipment offer a similar modifi-
cation for ~$50.
WARNING
THIS OPERATION INVOLVES UNSOLDERING ONE LEAD OF THE
CMOS MEMORY CHIP. CMOS DEVICES ARE EXTREMELY SENSITIVE
TO STATIC ELECTRICITY. USE THE APPROPRIATE EQUIPMENT
SUCH AS GROUND STRAP, GROUNDED SOLDERING IRON, ANTI
STATIC MAT TO MAKE SURE YOU WILL NOT DAMAGE THE CHIP.
THE SILK SCREEN REPRODUCTION IN THE ICOM R7000 SERVICE
MANUAL IS INCORRECT, REFER TO THE FOLLOWING DOCUMENT
CONCERNING LOCATING THE POSITION OF THE SPEECH SWITCH.
CONTACT ICOM FOR MORE DETAILS.
Equipment:
- anti static mat
- ground wrist strap
- tip grounded soldering iron
- solder (thin)
- set of screwdrivers
- unsoldering pump
- set small pliers wire cutters
Parts:
- photocopy of the exploded view of the R7000
from the ICOM R7000 service manual
- remote switch ICOM part # SPUT 19167A
- 47 K Ohms resistor
- small insulated wire
January 18, 1991
- 2 -
Time:
2 to 4 hours
II Preparation
Read this document completely. Select a smooth surface
to work on such as an antistatic mat or a towel spread
on a table. Put the R7000 in front of you with all the
equipment you will need at reach. The receiver must be
unplugged. For safety reasons and protection of your
equipment it is advisable that you leave the ICOM
unplugged for a couple of hours to allow components to
cool and capacitors to discharge. Take off the front
panel and the bottom panel as described in the exploded
views of the service manual. Disconnect and take off
the logic board (remember the connector positions).
Disconnect and take off the SW3 board it may require
disconnecting other boards.
III The memory module
Locate IC8 on the logic board. It is the chip with the
battery on top of it. Locate pin 19. Use the reference
in the service manual to find the correct pin labeled
A10 (page 7-9).
Top view of IC8
1 24
o U o
o o
o o
o o
o o
o o <- 19
o o
o o
o o
o o
o o
o o
Now think on how difficult it will be to unsolder pin
19. If you think it is beyond your skills, get help.
Unsolder pin 19 and use a pair of small pliers to pull
it out of it hole. Make sure it does not touch the
transistor nearby. solder a wire to pin 19. this wire
must be long enough to reach the front panel later on.
When this is done, verify that pin 19 is not in contact
with anything (you may want to isolate it). You have
done the most difficult part of the modification.
January 18, 1991
- 3 -
IV The switch board
Locate the speech switch on the SW3 board. Beware, the
ICOM service manual has incorrect information
(reversed) concerning the placement of switches on SW3.
The speech switch is S17. Locate the pattern/trace
below on the solder side of the SW3 board.
o
/ D31
wire A / o <-----------------Point P
#_____________/ /
_______ /
/ \ /
o o---o o Speech switch (S17)
#_______/
wire B
Unsolder the speech switch, the diode D31 and the wire
A. Insulate the wire A so that it does not touch any-
thing. Solder the 47K ohm resistor where the diode D31
was. Solder the new switch (SPUT 19167A) where the
speech switch was, in the same position. Solder the
wire that you have previously soldered to IC8 pin 19 to
Point P. Solder a wire between where wire A was sol-
dered and ground. A good place to connect to ground is
around the screw next to S18 on the SW3 board.
Ground
| o
| / 47K ohms
| / o ------------------> to IC8 pin 19
#_____________/ /
_______ /
/ \ /
o o---o o New switch
#_______/
wire B
Verify your work and reassemble the unit.
V Results
In the "out" position, the switch gives you the origi-
nal 99 memories, in position "in" you have 99 more
memories. These memories will be most likely full of
garbage, so the first step is to clear them using the
clear switch. Clear all the 99 memories.
This modification also double the program scan mode
memories. For example, you can have two programmed
scan depending on the position of the switch when you
do a "SET".
January 18, 1991
--
Jean-Louis Ecochard O
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(__Y__) uunet!sbi!chi!jl
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