Modifying the Radio Shack PRO-197 for Line Audio Out                                                                                 10 Nov, 2010  AI4JI  
   
This project was performed on 8 scanners for a client who wished to have recordable, line out audio, which was squelched by the radio's squelch circuitry but not effected by the volume control.
You can now connect the scanner to a recorder or to a computer to audio cast your scanner via the Internet, or for any other purpose that needs high quality constant level audio out.
 
Front view of the PRO-197                                                                                                             Rear View.. Remove the 4 screws

 
Mark the case where you wish to mount your jack.                                                                          Slide the case rearward and set aside.

 
Remove the 8 screws (4 per side) that secure the top and bottom covers.                                          Remove the Top cover.

 
Remove the Bottom cover, carefully unplug the speaker from the rear of the circuit board.                  Using a small drill bit, drill a pilot hole for the output jack.

 
The small pilot hole complete.                                                                                                        Now drill the hole out to full size to accommodate your jack.

 
The hole completed with the jack ready to install.                                                                            Jack installed and ready for connecting.

 
Look towards the upper middle of the main board.                                                                           Locate Pin1 of IC8. (Top left pin in this picture.)

 
Carefully solder a wire to Pin 1 of IC8, route it as shown above and thru a hole in the board.               Route the wire neatly from the hole to the tip of your jack. (case is ground, no extra wire needed)

 
Plug the speaker in, replace the covers and screws, replace the case and 4 black screws.                   The finished project.  I get about -4dBm of audio out, squelched and independent of the volume control!

 
   
   
   
   
   
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