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