Adding an Audio Line Output Connection to a MaxTrac Radio

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Back to Home Step-by-step Instructions for
Adding an Audio Line Output Connection
to a Motorola MaxTrac Mobile Radio
By Robert Meister WA1MIK
Maintained by Mike Morris WA6ILQ

If the front panel MIC jack has nothing plugged into it, you can get the Line Out signal directly from there by wiring up an RJ45 plug. Looking at the front of the radio, the top pin is #1; the bottom pin is #8. The audio can be obtained from pin 8 and the ground from pin 4. You don't need to do anything else. This works on ANY MaxTrac regardless of the type of accessory jack on the back.

On radios with 16-pin accessory jacks, use the RX AUDIO signal available on pin 11 of that connector and make sure that JU551 is set to position "B" inside the radio.

On radios with 5-pin accessory jacks, you're going to have to open the radio and add your own wiring by following the procedure below.

Open The Radio:

Turn the radio off and disconnect all the cables from it.

Remove the four flat-head screws (two on each side) with a T-10 driver.

Remove the two long screws in the front control panel with a T-15 driver.

Pull the front control panel forward about 1/4 inch if it hasn't already fallen off.

Flip the radio over so you're looking at the bottom. This is the board that the wires from the front control panel plug into. You'll be working on these connectors at the front edge.

Gently pry the bottom plastic case cover off the radio chassis. It must come straight up, so work each side equally front to back, side to side, until the cover can be removed.

Attach The Cable:

We'll be working with J8, so gently pull the blue connector plug forward until it is free of the connector pins. The pins are numbered 1 to 13, right to left. Pin 3 is missing but the spot for it is still counted.

Connect the hot lead of the cable (my cable has a red wire) to pin 4 of the connector marked J8. It can be tack-soldered directly to the back of the pin coming out of the circuit board.

Connect the ground lead of the cable (my cable has a black wire) to pin 10 of the connector marked J8. It can be tack-soldered directly to the back of the pin coming out of the circuit board.

Plug the connector that you removed earlier back onto J8. It is keyed and can only go on one way.

Close The Radio:

Route the new cable over the top of the front control panel connectors.

The radio is well sealed; there's no other place for the cable to exit. Cut a small notch in the bottom plastic cover or the corner of the front control panel plastic to allow the cable to exit the radio. The photo below shows two suggested areas circled in yellow. The cover can easily be replaced later if necessary. Note that I did NOT cut such a notch in my radio as the wire was added just for this article and it will be removed shortly.

Replace the bottom plastic cover. Slide it on evenly and parallel to the top cover. It should fit together snugly. Note that there is a front and back edge. The back edge is flat; the front edge has a lip that fits under the inside of front control panel. Just match it up with the top cover.

Replace the four flat-head T-10 screws (two on each side). Make them just snug. If they're tightened too much the plastic will crack.

Position the front control panel onto the front of the radio. It should fit over the lips at the edges of the top and bottom plastic covers. Secure it with the two longer T-15 screws.

Reinstall the radio and attach all the cables that were removed earlier.

Contact Information:

The author can be contacted at: his-callsign [ at ] comcast [ dot ] net.

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This page originally posted on Thursday 12-Aug-2010

This web page, this web site, the information presented in and on its pages and in these modifications and conversions is © Copyrighted 1995 and (date of last update) by Kevin Custer W3KKC and multiple originating authors. All Rights Reserved, including that of paper and web publication elsewhere.