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  Converting a Trunking 900 MHz MaxTrac to Conventional
An Alternate Method

By Greg Stahlman KJ6KO
HTML'd for Repeater-Builder by Mike Morris WA6ILQ
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A note from Mike WA6ILQ:
A recent thread on the AR902 Yahoogroup (which is oriented exclusively towards the 902 MHz Amateur Radio frequencies) covered converting a 900 MHz Maxtrac from trunked to conventional operation. The method discussed there works, but Greg described an alternate method that is simpler. I sent him an off-list email asking him write something up. I suggest that you read Bob Meister's article first for the background information there. Here is Greg's writeup:

This procedure simplifies the conversion process so only ONE program is required to do the conversion and NO realignment is necessary.

You will need:

First open the radio and replace the existing trunking firmware EPROM with the replacement FVN4019A firmware. Be careful that you don't fold a pin underneath, and make very sure that the notch in one end of the chip goes towards the RF shield. See the photo below. BE CAREFUL not to install the EPROM backwards!! It is instant death for the EPROM chip if you do!

Yes, the photo shows VHF / UHF firmware, but it also shows the notch...

If you try to blank the board with the trunking firmware still in it while using conventional RSS, it will give you the dreaded “MODEL NOT SUPPORTED”.

Now power up the radio. It will probably not operate and nothing will be on the display…this is OK.

Now connect to the computer, open the CONVENTIONAL LAB RSS.

Follow this procedure:

Do NOT use F8 for the third step!!!!!

Ignore the warning about “losing all data” and F2 to continue. It will take about 10-15 Seconds and it will return you to the service screen when it is done.


Click on the picture for a larger image

The F3 screen - ignore the color shifts, they are a product of the digital camera

Important: If the F3 option that is hhighlighted in yellow above is missing that means that the board was blanked using F8 “DO NOT SAVE OLD TUNE DATA”!
If you accidently blanked the board using F8 instead of F3, the F3 option will be missing and you will have to do a complete alignment on the radio!

It will now ask you for information. Enter the following:

The configuration process will take aproximately 20 seconds…… and you’re done!!

Note: You can convert a 2 channel Maxtrac to a 16 channel radio by replacing the 2 channel faceplate with one from ANY multi channel Maxtrac (even a super-cheap 800 MHz trunking one). BUT… you MUST swap the microphone connector and “HEARCLEAR” board from the old 900 radio faceplate into the replacement faceplate as the microphone jack and associated circuit board from the 900 radio is SPECIFIC TO THE 900 RADIO!!

Now read the radio and program the channels. NOTE the SCAN button and the rest of the buttons will now be in different locations than they were in a trunked radio. Your “new” panel will function as below:

You can buy a replacement excutecheon from Moto if you like. The multiple-channel conventional escutcheon is part number 1380277L01, for the 2-channel conventional escutcheon change the last character of the part number from a 1 to a 2.

Read the MAXTRAC USER'S MANUAL for instructions on the SCAN functions and other operational features.

At this point the radio has now been initialized as a conventional radio. Turn it off, disconnect the power cable, replace the shield over the microprocessor on the logic board, put the plastic cover(s) back on, and remount the control head to the front of the radio.

I have made several tests and verified that the old tune data is NEVER removed from the radio by “Saving Old Tune Data”. It was originally thought that the data was temporarily stored on the computer, but it is not. I tried several things to “brick” a Maxtrac this way like shutting off the radio and resetting the computer between blanking and programming the radio and the radio NEVER lost the tune data. You can actually blank a radio, put it on the shelf for a week and come back and initialize it and the old tune data will still be in it! The worse thing that happened was shutting off the radio or computer in the middle of programming the radio or in the middle of a “FULL ALIGNMENT”. When it was restarted, the radio gave a constant “death howl”, but I was able to start over with the process and when I got to where I was when it was shut off, the “death howl” stopped and the radio worked fine... still with the old tune data!

If the radio doesn’t work satisfactorily, you may, on rare occasion, have to return and do a complete alignment, which requires a GOOD service monitor, a test setup for the Maxtrac and about 45 minutes to an hour.
Some people would rather do a complete alignment anyway, and that’s OK, but I have done about one hundred 900 MHz Maxtracs this way for myself and others (we have a large 900 MHz group here in the Sacramento, California area), and have never found one that needed it. Most of us don’t have the required equipment to do a proper alignment anyway!

Some other notes on 900 MHz MAXTRACS...
The logic board (actually the audio/logic board) is the same on the low band, high band, uhf radios, and is unique on the 900 MHz radios. The 900 MHz board is unique and has several differences, two of which are important to us:

MaxTrac, PL, DPL, HearClear, and a whole lot of other things are trademarks of Motorola, Inc.

Contact Information:

Greg can be contacted at: his-callsign [ at ] innercite [ dot ] com.

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Article posted 05-Jun-2010

Article text copyright 2010 by Greg Stahlman KJ6KO
Conversion to HTML © Copyright 2010 for Repeater-Builder by Mike Morris WA6ILQ

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.