EEPROM lock instructions
All parts and tools are available at your local Radio
1. Switch, Single Pole Double Throw (SPDT)
2. Resistor, 1K-Ohm ¼ Watt
3. Wire, Wire Wrap type wire preferred
1. Soldering Iron, (NOT a soldering GUN)
2. Pencil type 30-45 Watts
3. Solder, Rosin Core, .062" diameter or smaller,
4. 60/40 Tin-Lead mix Soldering Aids,
5. Pick type tool to lift pin
Switch Wiring Instuctions
EEPROM Pin Out Diagram:
Referring to the graphic below, the "Asterisk" denotes pin-1 on all DIP (Dual
Inline Package) styled chips. Some chips may have a "dimple" while others may
only have the "U". The pin to the LEFT of the "U" IS pin-1, in case
your EEPROM chip does not have the "dimple".
The pin out on the EEPROM is as follows:
1. Drill a hole in the back of the IRD frame, and mount the SPDT switch so that the
legs/pins on the switch are lining up in a vertical manner.
2. Locate the serial EEPROM. This IC is an 8-pin chip usually surface mounted, and most
are a Microchip 24LC16B.
3. Lift pin-7. To do so heat the pad and use a dental pick tool to gently lift the pin
from the copper land.
4. Solder a wire from the lifted pin-7 on the IC to the center pin of a SPDT type
5. Solder a wire from pin-4 (Vss or Ground) to the bottom pole of the switch.
(Do not use the pad from pin-7 since the space between the lifted pin-7 and the pad is so
small, that doing so can cause short).
6. Solder a 1K-Ohm ¼ Watt resistor to the remaining leg on the switch.
7. Lastly solder a wire from pin-8 of the EEPROM to the free leg on the 1K Ohm 1/4 Watt
With this modification controlling the EEPROM is now that much easier.
To UNLOCK the EEPROM, flip the switch lever so that it points UP.
To LOCK the EEPROM flip the switch lever so that it points DOWN.