[Medyk]

Remove the 4 screws securing the case halves together. Remove the bottom screw securing the front case half to the chassis.
Being careful not to lose the battery latch return spring, separate the front case from the chassis.
Locate the 4 jumper pads marked, A, B, C and D.
No jumpers applied to any of these pads will allow for the standard 40 channels band plan.
Next locate the feed through point labled "E", this is the point that is grounded to provide a reset to the microprocessor
Jumper only pad marked "A" for 120 channel operation. This will provide 40 normal CB channels, plus 40 channels above and 40 channels below the standard channels. Coverage from 26.515 MHz to 27.855 MHz. The "A" channels are not covered. (i.e. 3A, 7A, 11A etc.)
Jumper pad marked "A" and "B" for the new European 80 channel band plan. Channels 1 -> 3 are FM mode, Channels 4 -> 15 are AM mode, Channels 16 -> 80 are FM mode. Note that channels above channel 40 are lower in frequency then channel 1.
Jumper "B" only gives the UK FM mode band plan.
After changing any of these jumper pads it is necessary to ground the feed through at point "E" to force a reset of the microprocessor.
As far as I can tell jumper pads "C" and "D" do nothing at all. If anyone can add to this information, or provide insight as to other jumper pad configurations please provide feedback to us here.