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 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~./_\.~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ (__Y__) uunet!sbi!chi!jl