copied from the internet: From: pas@jupiter.ic.cmc.ca (Peter Stokes) Newsgroups: rec.radio.shortwave Subject: alt.scanner ---------------------------------------------------- Hi. A note to BC760XLT scanner owners. I recently agreed to modify one for a friend a found the following two notes of interest. 1. It was shipped with a how-to on the cellular restoration mod that appears more comprehensive than those I've seen WARNING: If you don't know enough about electronics and about what you are about to do, you might toast your radio and if you toast your radio, you only have yourself to blame; you can't blame me or anyone else! Also, the moment you twist a screw to remove a cover, your warranty is gone! Also, monitoring of certain services in certain freqency ranges is prohibited in certain areas. a) The following applies to models manufactured during 1989 (HI code date suffix) or later. b) Place radio so the front is facing you; remove top cover c) You are looking at the FOIL side (other than surface mount components and a large upside-down Sanyo IC) of the PCB. Locate this Sanyo IC. A long row of solder pads just above the Sanyo IC identifies pins 1-32 of the microprocessor. Pin 1 is on the left and pin 32 is on the right. d) Using a sharp-pointed tool, cut the two traces leading to pin 26 of the microprocessor IC. There is a trace coming from above pin 26 and a trace coming from below pin 26. e) Solder-bridge pins 19 and 20 together of the microprocessor IC. f) Solder-bridge pins 26 and 27 together of the microprocessor IC. g) This part is tricky to identify without a diagram. Directly above pin 27 is a three terminal, surface-mounted transistor device. The lower terminal of this device used to be connected to pin 26 of the microprocessor IC until you did step d) above. Solder-bridge together the two left-hand side terminals of this device. h) This part is also tricky to identify without a diagram. Locate the trace that travels from pin 19 of the microprocessor IC to pin 26 of the microprocessor IC. Near pin 26, this trace will have been cut as per step d) above. Along the length of this trace, there are two devices that are physically mounted over it. Of these two devices, the two-terminal device on the left-hand side is a 4.7k chip resistor marked "472" on it. It is mounted over the trace in an area approximately below pin 20 of the microprocessor IC. Carefully remove this chip resistor and tape it to the inside of the scanner cover, just in case... i) Put the radio back together and try to enter 845. If 845.000 appears on the LCD, you've done the mod successfully. 2. A $60 option for the BC760XLT is a CTCSS tone decoder board that plugs directly into the scanner board. Catalogues indicate you must purchase a $10-$15 switch assembly in order to enable/disable the CTCSS option. You do not need to buy this switch if you are comfortable enabling the CTCSS as follows: a) Following installation of the CTCSS card on the component side of the circuit board, you will have used two row-pin connectors (one that the CTCSS board plugs directly into and one for a ribbon cable leading from the CTCSS card). This leaves a third, five pin, row connector unused in the general area of the CTCSS card. This is where the "required" switch is supposed to plug in. b) Locate this 5-pin connector on the FOIL side of the PCB and mentally number the pins 1 to 5, from left to right (with the radio front facing you). The CTCSS option is enabled by connecting pin 5 to pin 2. I did this by running a wire from pin 5 to the top of the surface-mounted component directly above pin 5 (which is connected to a large foil area which is connected to the (mentally numbered) pin 2). Use your fine soldering skills to do this however you like. c) On power-up, the string "CTCSS" will appear on the bottom right of the LCD display. The instruction guide tells you how to punch in PL tones to use the CTCSS option. I did the above two mods and have found the radio to be working flawlessly. Your mileage may vary. Now I have to return the radio to my friend... but without some further "testing" of course... :-) Peter pas@jupiter.ic.cmc.ca ========================================================================== Note: I haven't tried or verified this, proceed at your own risk. WA2ISE