Service Manuals

Here are a listing of the Service Manual part numbers for this series of radios:

• 6802945C75 -- GTX 800 Service Manual, Portable
• 6802945C70 -- GTX 800 Service Manual, Mobile
• 6802948C90 -- GTX 900 Service Manual, Portable
• 6802945C85 -- GTX 900 Service Manual, Mobile

GTX Portable

The programming cable for the GTX is the same as the GP300.

GTX Mobile

The programming cable for the GTX is the same as the Maxtrac/Radius series.

The mic connector pinout is the same as the pinout of the Maxtrac/Radius series.

If you make a mic plug with a jumper from pin2 to pin5 (see the schematic above for numbering convention), you will make a "Test Plug" to put the radio into test mode. Turn the radio on and in 3 seconds the radio's receiver will open up and your in the test mode.

The pinout of the accessory connector is below:

Pin 13 Configuration:

For internal speaker remove L417 and install R455 and L435

For Switched +12v Remove L435 and install L417 and R0425 (0 ohm resistor)

For ground Install Remove L435 and install L417 and R0426

Note: Do not install R0425 if R0426 is installed, this will severely damage the radio!

Looks like the logic board in the GTX is similar to that of the Maxtrac, it may be possible to hack a couple more channels into conventional mode.

General Information

Below is a model list for the GTX radios:

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