PRO-2004 400 Channel & Speed Mod

 

These mods are well documented online, but few decent pictures exist.  This is my version.  My addition to this project, is adding a 400 Channel Overlay to the keypad.  This will correctly identify the new channel layout.  Also makes an old keypad look like new again.

I bought my 1N4148 signal diodes from Digikey.  Here's a direct link to the part.  Ten of them only cost $0.56.  They are also available from many sources, including Radio Shack.

 

 


Remove the 4 screws from the back of the case, and slide the cover off.  On the bottom of the scanner, the large metal RF lid is needs to be lifted off.

Underneath, the microprocessor is on the right, the row of diodes on the left.  We'll be adding two diodes.  Go ahead and remove all the screws holding the board to the chassis.  The soldering will be done on the backside of the board.

Most of the diodes are clearly labled.  They are in sequential order.  The top, unmarked spot is D510.  Adding a diode in this location will add 100 channels, expanding the total memory to 400 channels.  The unmarked spot between D513, and D515, is obviously D514.  Add another diode here to increase the scan rate from 16 channels per second, to 20.  Not a huge increase, but if you're doing the memory mod anyway.  Removing D513 would permit listening to a blocked portion of the 800 MHz band.  But it's all digital now, so don't waste your time.  It's also illegal, nuff said.

I can see why so many PRO-2004 scanners had issues with cold solder joints.  Many of mine look bad!  There was a blob of solder in the holes where my two diodes needed to be placed.  You can use a piece of solder wicking braid to pull it out.  I'm fortunate enough to own a PACE station, with a solder extractor.

The two new diodes are now in place.

A closer view of D510, and D514 installed.  Button it up, ready to enjoy the upgrades.

 

 

 

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Last updated 06/23/14    All rights reserved.