REALISTIC PRO-32 SQUELCH MODIFICATION
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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