remove top cover of radio by removing all 8 screws.
disconnect speaker and move top aside.
locate the cpu on the radio, it has a crystal glued to the top of it and is located in the front left corner of the radio, it's the largest ic in the radio.
to the extreme left of the radio, you will see a row of pads, all empty except for a diode to the front, and one to the back. there are about 6 or 7 spots for diodes, but only 2 installed.
remove the front (closest to head of radio) diode with a small soldering iron or other tool.
turn the radio back on, it will automatically reset.
you now have ext coverage eg. tx 450-470, tx 150-170, etc...
