The following document explains how to modify a Radio Shack Realistic Pro-2004 scanner to receive the 800 mhz cellular telephone frequencies which were disabled prior to the unit being sold.
This modification is specifically for the Pro-2004. There are other mods available for other scanners, but this document does not cover those.
This mod is simpler than the one done by Rep Tauzin. Tauzin had to use a soldering iron to modify the scanner he used to demonstrate the ease and simplicity involved. This mod does not need a soldering iron, unless you desire to do one or both of the additional mods not associated with receiving cellular frequencies.
If a U.S. Representative can do it, so can you.
Tools required:
You assume all risk, legal and technical, if you decide to undertake this modification. While it might be illegal to modify a scanner to receive cellular communications, certainly it can't be illegal to have, obtain or distribute the information detailing how such a modification can be done.
1. Remove the four screws from the back of the radio, and slide the cover off of the scanner chasis.
2. Turn the scanner upside down. In the center of the circuit board, you will find a shielded enclosure. Remove the cover of the enclosure and rotate the scanner so the front panel is towards your body.
3, On the right side inside the enclosure, you will see the CPU for the scanner. On the left side you will see several diodes and resistors, and blank pads for diodes.
4. Near the top of the column of diodes, you will find one labeled as D513. You may clip one lead of D513 and separate the leads so they do not touch. This restores cellular coverage to the Pro-2004.
4a. NOTE: If you plan to attempt the 400 channel or speed-up mod, you may want to desolder the diode instead for use in the additional mods.
If you do not intend to do either of the additional mods, skip to step 7.
If you need to get to the underside of the CPU circuit board, use extreme care so as to not damage any wires or circuits.
5. 400 CHANNEL MOD: Count from diode placement pad D513 uo to D510. (The D510 pad may be unlabeled). By installing a diode in position D510, in the same polarity as the other diodes in the stack, you will increase the number of memory channels from 300 to 400.
6. 20 CHANNELS PER SECOND MOD: D514 is just below D513, the diode you clipped to gain cellular coverage. By installing a diode in this position, in the same polarity as the other diodes in the stack, you will increase your scan speed from 16 CPS to 20 CPS. (This might not be preferable if you scan a lot of weak signals, as the speed could cause them to be skipped.)
7. Before replacing the cover on the shielded enclosure, make sure that you have not left any wire or solder droppings within, which could cause shorts.
8. Replace the cover on the shielded enclosure, making sure all the retaining tabs engage. Slide the scanner chassis back into the case and replace the four screws on the back.
That's it.
NOTE: With the 400 channel mod, you now have 40 channels per bank rather than 30, so the small bank numbers on the keypad will no longer be accurate.
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