Modifications for the Standard C-508

19-07-1998 Standard C508A TX 115-164 & 400-464


The following procedure involves removing the lithium battery which saves your memory channels. Note any memory channels you wish to save -- you will have to re-enter them. Also note the placement of the battery before you remove it, since you don't want to put it back in the wrong way.

Remove the 4 screws from the back of the radio and separate the front and back pieces. Be careful not to damage the flexible cable connecting the two. Unsolder and remove the lithium battery, being careful not to short-circuit it. Remove the surface mount chip resistor RD77, at the fifth pin of the CPU chip, counting up from the bottom. Two component pads above it are already empty. To permit RX of cellular, also remove the surface mount component depicted in the diagram above, way in the upper right-hand corner. Resolder the lithium battery back into place, noting that the polarity is correct. Press the reset switch, and reattach the two halves of the radio. Place the batteries back in and power on.

        top right-hand corner


                 |     |          |
                 |     |          +-----+
                 |     |           o  o |
                 |     |              # | <- remove this SM component +-----+ o o | for cellular RX unlock | | | | | | // | // CPU | | o o | | o o under / | o#o Lithium / | battery / + | ^ | | | remove this SM (RD77) | component to extend | TX 115-164 & 400-464 |