REALISTIC PRO-32 SQUELCH MODIFICATION ===================================== The modification outlined below "tightens up" the squelch control of the Realistic PRO-32 handheld scanner. The original squelch control has a lot of hysteresis built in, meaning that if you turn up the squelch until quieting is achieved, you'd then have to turn it quite a ways down to deactivate it. The modification moves the activate/de-activate levels much closer together, giving the squelch a much "tighter" feel. This modification will, of course, void any warranties that may apply to the scanner and should only be attempted by people with experience in electronic assembly and soldering techniques. Here's what you need for the modification: - A large, clean, well lit work bench. - A small Phillips screwdriver. - A fine tipped soldering iron. - A medium flat blade screwdriver. - A solder removal tool (solder sucker). - 1 small wire tie. - A 120k Ohm Resistor, 1/8 or 1/16 Watt. Now, let's do it... - Invert the radio. Remove the battery cover and battery pack. - Remove the six small Phillips screws that hold the radio together. NOTE: The two shorter screws go in the battery compartment. - Now remove the back cover. Carefully examine the radio. You will see the analog PC board. Along the top is the Earphone jack, along with the Volume and Squelch controls. Near the bottom of the PC board, just above the battery compartment, is IC101. To the right, directly beside IC101 is a resistor R163 (27k Ohms). R163 will be replaced with our 120k resistor. - Clip the wire tie holding all of the wires on the top of the PC board. You can discard the wire tie, as you'll be replacing it later. - Unplug the four wiring harnesses that go to various points on the PC board. They are unplugged by gently pulling on the plug body, NOT THE WIRES. - Remove the knurled nut from the Earphone jack using a sharp instrument. - Remove the four round brass nuts from the top of the PC board using a medium flat blade screwdriver. - Now, gently prying on all sides, remove the analog PC board. Notice that the Earphone jack and the PWR/CHG jack will come out along with the PC board. NOTE: There is a 17 pin con- nector along the top of the PC board that is hard to pull out. By continuously applying pressure to different areas along the top of the PC board, the connector will come apart. - Once the PC board is free, swing it out as far as possible, taking care not to damage any components or pull out any wires. - Unsolder and remove R163 (27k Ohms) from beside IC101. - Install your 120k Ohm resistor in R163. Solder and clip off excess lead length as close to the PC board as possible. - Re-assemble the radio in reverse order as above. Pay attention to the position of the Earphone and the PWR/CHG jacks when re-installing the analog PC board. Use a new wire tie to tie off excess wire lengths on top of the PC board. - Once re-assembly is completed, install the batteries, or an AC adapter/charger and test the radio. All features should operate correctly, and the Squelch control should be much "tighter". Once again, this modification will void any warranties applicable to the radio, and should only be attempted by people experienced in electronic assembly and soldering techniques. I'm sure that with the above instructions, any radio/tv repair shop will do the modification, although they may not guarantee it, since it isn't a manufacturer approved modification. The above modification has been performed on three different PRO- 32 scanners, and all have had no ill effects. ENJOY!!! Ray Semenoff 73637,341