maxtrac 2 to 16 channel conversion

techno · Post by **techno** » Sat Jun 25, 2005 7:07 pm

I've heard yopu can convert a 2 channel maxtrac to a 16 channel maxtrac by replacing the 2 freq head with a 16 freq head. I have replaced the head and now need to know what you do in the rss to make it work. Radio is a D44MJA73A5_K, UHF, 449-470. Thanks,

Ron Harroff
WA9LAY
MAXTRAC ROOKIE

Woody_99 · Post by **Woody_99** » Sun Jun 26, 2005 12:43 am

Well... that's always a good question to hush an entire room!

Best advice for a rookie is to start in the info pages to stay outta trouble.

I can tell you without a doubt that the head change has only prettied up the front of your radio with a display.
You will need more, indeed.
There are several routes to go, but the easiest method is to use a BLANK LOGIC BOARD which you can reinitalize as a 32ch radio. [Depending on your eeprom]
There is a ton of info on the board already, in the model specific info, namely this one:
http://batlabs.com/maxrad.html

Now the fun part.... chances are your radio will only do 16ch with the existing logic board and eeprom, unless you have a socketed eeprom you will be stuck at 16. If it is socketed, then all you need is a larger capacity eeprom for holding the 32ch and signalling options.
Monty was my only source for said eeproms, so I have not a clue where to find them now.
Still, blanking the board will be your biggest problem.
And with that, I refer you to this link:
http://www.batlabs.com
11th text line down, in blue.

Good luck, and feel free to ask advice and questions!

Post by **xmo** » Sun Jun 26, 2005 6:31 am

http://www.repeater-builder.com/maxtrac ... index.html

Bob · Post by **Bob** » Sun Jun 26, 2005 8:52 am

The eeproms are still available from Motorola. Part number HLN5569A. List price is about $25.

NikolaTesla · Post by **NikolaTesla** » Mon Jun 27, 2005 11:45 am

If you the logic board with the 14 pin connector on back, you can do the 32 channel upgrade and/or convert to trunking as well. You need an uploaded image from one of those radio's and a new front. Of course the cable and software too. Piece of cake.

redbeard · Post by **redbeard** » Mon Jun 27, 2005 12:23 pm

If you find that you have the masked board with the 5-pin connector there is another way. Find some cheap 800MHz trunked Maxtracs that are out there everywhere for 10-20 bucks. These can have a 5-pin connector but usually have the 16 (more desirable) and you can pull the trunking firmware and order the eprom that Bob mentioned above. The board should be blanked with Lab RSS then reinitialized (with standard RSS, look inthe service menu) as Max High Sig and the appropriate bandsplit and channel capacity you want. The panel number is what determines whether it is a 2, 6, 16, 32 channel so read the help about that when it comes time to input the panel number...it will tell you what to use. You will also need some of the numbers from the crystal and a voltage measurement from a pin on the big connector in the center of the board.

I've built plenty of VHF radios this way for ham purposes. They work great but need aligned after the switch. You can go into the radio first and write down all the settings to 'ballpark it' but it will still need fully aligned further to be perfect.

NikolaTesla · Post by **NikolaTesla** » Mon Jun 27, 2005 12:33 pm

I used to use old eproms purchased at hamfest for $1 each. Used the sun to erase them and generic eprom writer. Real part is easier if you don't have that stuff. Ya got to have 1 real one to read first.

kb0nly · Post by **kb0nly** » Mon Jun 27, 2005 1:33 pm

If you have a Logic board, 5 pin or 16 pin with the removable Eprom then you can upgrade without further work. So check that first! Just take the bottom cover off the radio and then it will be obvious, if there is a shield over an area of the logic board remove it and you will see the firmware eprom.

If there is no shielded area than you have a low option logic board. Which is most likely on a 2ch radio.

Otherwise you will need to replace the logic board with a blank one and initialize it to match the radios band and power level.

As far as the Eprom, its just a plain old 27C256, i get them from Mouser.com or Digikey.com for about $1.50-$2.00 depending on manufacturer for the OTP style. These are One Time Programmable and don't have a window for UV erasing. Which of course is not a problem being a firmware Eprom, unless you needed to upgrade the firmware in the future for some reason, unlikely since the Maxtracs are NLA from Moto.

I have bought a bunch of used Eproms from eBay before also, a large batch of pulled parts, then you just need to erase and reprogram them. If you have an Eprom burner just buy some OTP Eproms new and go for it! Keep them 200ns or faster, i had one radio act odd when i used an Eprom that didn't have the speed labeled on it. Turned out it was a 250ns Eprom and the radio had a hard time booting up, sometimes it would, and sometimes it would fail and go to the constant tone.

If nothing else, let me know and i can help! I have a couple blank Eproms left over from a previous project. I also have a 16 pin logic board in a 800Mhz Maxtrac that i bought for parts. Since you already have the full feature front panel the most you would need to buy is a logic board and Eprom from me, and labor, for which i accept trades, and you would have a full feature 32ch Maxtrac. But check and see what you have for a logic board. Did the radio you pulled the front panel from have a 16 pin logic board?

redbeard · Post by **redbeard** » Mon Jun 27, 2005 6:14 pm

Man I sure miss working where I used to, with access to the EPROM burner and all! I originally bought a real chip from ebay a while back and then proceeded to copy a bunch off for myself. Upgraded a couple Kantronics TNCs while I was at it too. Man I miss that job....

Oh, and I think the low option board is at least good for 6ch with a blank and re-init...just no signalling besides pl/dpl.

kb0nly wrote:If you have a Logic board, 5 pin or 16 pin with the removable Eprom then you can upgrade without further work. So check that first! Just take the bottom cover off the radio and then it will be obvious, if there is a shield over an area of the logic board remove it and you will see the firmware eprom.

If there is no shielded area than you have a low option logic board. Which is most likely on a 2ch radio.

Otherwise you will need to replace the logic board with a blank one and initialize it to match the radios band and power level.

As far as the Eprom, its just a plain old 27C256, i get them from Mouser.com or Digikey.com for about $1.50-$2.00 depending on manufacturer for the OTP style. These are One Time Programmable and don't have a window for UV erasing. Which of course is not a problem being a firmware Eprom, unless you needed to upgrade the firmware in the future for some reason, unlikely since the Maxtracs are NLA from Moto.

I have bought a bunch of used Eproms from eBay before also, a large batch of pulled parts, then you just need to erase and reprogram them. If you have an Eprom burner just buy some OTP Eproms new and go for it! Keep them 200ns or faster, i had one radio act odd when i used an Eprom that didn't have the speed labeled on it. Turned out it was a 250ns Eprom and the radio had a hard time booting up, sometimes it would, and sometimes it would fail and go to the constant tone.

If nothing else, let me know and i can help! I have a couple blank Eproms left over from a previous project. I also have a 16 pin logic board in a 800Mhz Maxtrac that i bought for parts. Since you already have the full feature front panel the most you would need to buy is a logic board and Eprom from me, and labor, for which i accept trades, and you would have a full feature 32ch Maxtrac. But check and see what you have for a logic board. Did the radio you pulled the front panel from have a 16 pin logic board?

kb0nly · Post by **kb0nly** » Mon Jun 27, 2005 6:17 pm

Yep, there is a low option 6ch board as well. I just meant to say that his two channel radio is most likely a low end 5 pin logic board that is non-upgradeable to what he wants.

Having an Eprom burner is nice, i finally put out the cash to buy one, and it easily paid for itself in the first week of use salvaging radios.

Jim202 · Post by **Jim202** » Tue Jun 28, 2005 4:35 am

There is a mod you can do to the 5 pin boards to make them work in the modified trunking mode similar to a 16 pin logic board. It only takes a 1/8 watt 10K resistor , cut a land and add a jumper. Have done it to a number of 800 maxtrac radios.

Just remember that the Maxtrac will not work on splinter channels in the trunking mode. Other than that they will make a good scanner for trunking. Just don't forget to disable the PA by pulling the 12 volts and pulling the driver cable. Make sure you don't allow affiliation.

Jim

techno · Post by **techno** » Tue Jun 28, 2005 8:16 am

Thanks to all who have replied! I have enough info to get started. The radio is a 2 channel uhf 449-470 with a 5 pin accessory jack. I hope I have the good logic board. I will PM some of you for more help and advice if I can't figure it out. I am a rookie on most Moto stuff and am enjoying the learning experience. Thanks again and 73,

Ron Harroff
K9RH
(formally WA9LAY)

Woody_99 · Post by **Woody_99** » Tue Jun 28, 2005 3:15 pm

http://www.repeater-builder.com/maxtrac ... grade.html

The exact page on the link provided by xmo, showing you what a socketed chip looks like. If your board is any different, then you're probably stuck at 6, 8 , or 16ch. Don't panic if you find your board is red, just look as shown for the firmware eprom.

peace,

elesjuan · Post by **elesjuan** » Tue Jul 19, 2005 9:38 pm

I wanna pop in here and ask a couple questions. I have a ton of friends that use GMRS and FRS radios to communicate in our cars, bikes, and out and about.. I have a pair of Maxtrac 800MHZ trunked radios, one is a MAXTRAC800 and the other one is the digital display 800mhz maxtrac with the 16 pin connector. Don't recall 100% which model it is, but I can supply specific details soon

Basically I want to convert the 800MHz units to 462.xxxxMHz range and I was looking for some info on how to do this.

From what I've gathered, I have to remove the EEPROM from the logic board of the radios and purchase a new EEPROM from "Bob" for about $25.00 that has the proper software installed. I have access to RSS through my companys administrator (he owes me some favors so he can do some programming I ask).

Am I on the right track?

Woody_99 · Post by **Woody_99** » Tue Jul 19, 2005 10:36 pm

Hey,
well... no... You're on the race track and your radio is on the train track.

First things first....

You need a license to transmit on GMRS over 500mW
to be legal. [maybe it's one watt? Maybe no tx at all without a license.]

You can't use a maxtrac to transmit on FRS because you can't turn the power
down to stay legal. Power limit on FRS is 500mW, or half a watt.
[unless you have a GMRS license and then you can plow it up on the first 7 channels with 5w.]

The 800MHz Maxtrac will need the RF boards, PA and what-not changed out. Basically everything EXCEPT the logic board. And then you still need to change the EEPROM or firmware.
Easiest way to do that is to get on ebay and buy a UHF maxtrac for $100 for parts then just use the UHF maxtrac....

Sorry, couldn't resist.. Just kidding around. It isn't worth the time/effort/money to replace 80% of a radio. Just get the UHF radio you need. [don't forget the license!

]

The EEPROM on the logic board holds what is called Firmware. The 800MHz radio is pretty well only useful for removal of its logic board
to use on another radio. Then the firmware or chip itself is exchanged for the proper UHF/VHF or whatever radio you put it in.
The way to think of it is that the 800MHz radio is a "parts" radio, not the other way around.

So it boils down to no, you can't really convert it. Just grab a used UHF radio.

So who is Bob??

peace,

elesjuan · Post by **elesjuan** » Tue Jul 19, 2005 11:36 pm

Well Crap on a stick. Want a couple maxcrap radios? lol. Knew I shoudln't have bought those damned things. Thanks for all the info.

Have a license for GMRS and some 2 watt radios that I use with quite a good deal of range, but they're mounted to motorcycle helmets. The good old "Chatterbox" radio.

The UHF Idea is a much much better idea just wish I would have known that before I wasted 40$ on a pair of crappy Maxtrac 800mhz radios. Are the logic boards in these 2 radios even worth anything, or should I Just relist them both on ebay and hope to get 10$ for the pair?

Don't know who "Bob" is, I misread whoever was selling the EEPROM in the previous sections of this specific thread.

Had one last question about FRS and GMRS; Are they both on the exact same frequencies, or is GMRS 7FRS + A few extra? My Chatterbox GMRS-X1 radios have 15 channels and I couldn't seem to find exact fequencies on the web that they operate on so I broke out the frequency counter to come up with some STRANGE results;

CH Frequency (MHz)
1 462.5610
2 462.5860
3 462.6110
4 462.6360
5 462.6600
6 462.6860
7 462.7110
8 462.5735
9 462.6235
10 462.6735
11 462.5490
12 462.5985
13 462.6480
14 462.6985
15 462.7234

I have the older model RadioShack frequency counter that I hardly know how to use well but thats what I came up with. Would also like to mention that the battery on the X1 wasn't fully 100% charged, so they might be strange because of that?

Woody_99 · Post by **Woody_99** » Wed Jul 20, 2005 6:58 am

Hey, sorry for the sad news.

In the big photo montage the FRS channels fall right between the GMRS channels. Go here and get the goods on GMRS/FRS/MURS/ETC:
http://www.provide.net/~prsg/home.htm

If you use a lot of radios, the 800 maxtracs are good donors for everything except the RF and PA stuff. Good plastic, mics, brackets, whole front heads, etc. But if you're on a budget, they should sell for $20 each if you list them right. Mention the 16pin LOGIC BOARD in your ad for those that are upgrading their 5pin radios.
OR if you're planning on getting maxtracs in UHF, keep the mics/brackets and sell the radios for $15 each. Still a good investment.

GMRS is 25kHz and FRS is 12.5kHz spread.
Your freq counter isn't going to hit them exactly, unless it's quite expensive. Your counter appears to have an error of about 15-20khz, [reading low] and when trying to nail a 12.5kHz freq in 4 digit resolution, you're chasing your tail. I say it's the counter because of the somewhat consistent error. Low batteries, movement and distance can cause error also, but yours is like my Rat Shack counter; it's off a certain degree [and now you know how much at UHF] so remember that. Forget trying to prove a GMRS vs. FRS frequency with it though. They're too close.

Check that page above for the exact freqs of both services.
Rule of thumb, All the listed freqs ending in 3 digits and a zero will be GMRS and the split ones ending in 4 digits and a 5, like 462.5625 will be FRS; as they fall between each GMRS channel. [not discussing the freq counter here. Only known a known frequency.]

I prefer MURS; it VHF, better range, nobody knows about it, nobody is on it.

[at least around here.]

I have a GP350 UHF handheld I'll put on GMRS/FRS and trade ya for the chatterboxes! hehe...

peace,