Interesting Maxtrac firmware/codeplug IC

bellersley · Post by **bellersley** » Tue Apr 10, 2007 9:12 am

I came across this in a "junk pile" radio. It's an 800MHz Maxtrac, model D35MWA5GB7AK.

There are 2 IC's in the pic. The one that is the oddball one is the one that is next to the socketed IC. It say the following embossed on the chip:

"DALLAS DS1220AB 8827 S NONVOLATILE SRAM"

However, someone has taken pencil and written (from the best that I can tell, it's faded pretty bad) "3147US" and "6/1 6311 515(2)"

The socketed chip also doesn't have any Motorola labels on them like you'd expect. It's just a run of the mill 27C256.

I did a search on the Dallas chip, it's apparantly 16k. The regular chip that you'd find there is also 16k, so I'm not really sure what the difference is.

Again, sorry for the terrible quality.

Does anyone know what the story is? It reads just the same as the other radios in the pile, it's a Type I 10x10x10 radio, nothing seems different from any other radio of the same type.

Jonathan KC8RYW · Post by **Jonathan KC8RYW** » Tue Apr 10, 2007 10:35 am

I have an 800 MaxTrac with a similar Dallas module -- DS1220AB.

The radio was modified heavily -- DB15 running out the back, traces cut, etc.

It has an 27C256 EPROM that says Motorola RADIUS DIVISON Version 62.02. I guess I could read it on the E/EPROM programmer if anyone cared for me to take a look at the binary for the part number.

If I recall, when I read it with RSS, it was 0 systems, 0 subfleets, 0 conventional modes.

Victor Xray · Post by **Victor Xray** » Tue Apr 10, 2007 11:10 am

Dallas Semiconductor Nonvolatile RAM. They've been discussed here in the past. Jackhackett knows a bit about them.

http://batboard.batlabs.com/viewtopic.p ... 754#308754
http://batboard.batlabs.com/viewtopic.p ... 362#147362

bellersley · Post by **bellersley** » Tue Apr 10, 2007 11:18 am

Quite interesting.

Going by the serial number, the manufacture date is 1989. The PC board is also a red colour instead of the typical green that the other radios have.

It seems to work just fine however. But, I'll hold off from using it unless I have to, incase the battery has gone south.

Thanks for the infos!

PETNRDX · Post by **PETNRDX** » Tue Apr 10, 2007 2:35 pm

I have seen a lot of those also.
Probably a case of the NOVRAM being cheaper or better availablity than the EE prom.
A couple of years ago I was still able to find those NOVRAM IC's.
They were something like 3 bucks, and if memory serves, I got them from one of the usual places (Newmark or Mouser).
They were also used in early community repeater panels by CSI (WA not CA) and I think by a couple of other manufacturers.
At the time it was cheaper to replace the NOVRAM than toss the radio or repeater panel.