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  MaxTrac Series Introduction
By Neil Johnson WBØEMU
HTML'd and edited by Mike Morris WA6ILQ
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From an email from Neil to repeater-builder:
I saw a mention on the yahoo AR902 group that you have added the 900 firmware part number to the Repeater-Builder MaxTrac series pages.

I have some additional notes about MaxTrac firmware and board part numbers I thought I would pass along....   I think the MaxTrac series of radios is of general interest to 'repeater builders' since they have many applications as repeater receivers, exciters, transmitters, control receivers, and links.

One item in these notes that I will draw attention to is the fact that the Radius M214 and M216 models are very similar to a MaxTrac except for a different plastic front and different firmware.   The reason I note this is that the Radius firmware supports channel steering from the accessory port control lines and none of the Maxtracs can do that trick.   Channel Steering makes it possible to easily use one of these units as a frequency agile (or PL agile) transceiver or link, controlled by output lines from your repeater controller.   You can program up to four lines to give you up to 16 channels (one line gives you 2 channels, 2 lines gives you 4, 3 gives you 8, and 4 gives you 16. You have 5 input lines available, so you can do 16 channels plus one additional function - transmit PL inhibit, for example)

Using instructions you have on the Repeater-Builder site, a 16 pin logic board, the range RF board you want, and the right firmware, a person can 'create' a radio customized to just about any application.

Note from WA1MIK:
All Low Band, High Band, UHF and 800 models use the same control head components (microphone jack/volume control board, display board, loudspeaker, escutcheon, plastic parts, cables). The 900 MHz radio uses a different microphone jack/volume control board which also contains the HearClear module and circuitry. There are significant signal differences on the 900 MHz logic board and MIC/VOL board that prohibit intermixing of these assemblies.

Notes follow:

Here is a list of the MaxTrac firmware that I've found in the radios that I've worked on.   Some cautions apply to this list: For example, it is generally regarded that the version 5.34 of the HLN5569A conventional firmware is the latest that was used in non-900 MHz mobiles.   I verified that it was used in one of the newest MaxTracs I ever saw - one with a June 2000 date code, however, I have seen a chip labeled HLN5569B V.5.36 49 / 95.   This "B" version chip was found in one of the two transceivers in a UHF Desktrac repeater housing.   What could the difference be ? I have no idea!

The firmware version number will be on a label on a socketed EPROM chip that is under a metal shield on the logic board.

You might want to print and cut this page and stuff it in your pocket before the next hamfest...
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MaxTrac Series Firmware
Numbers in parentheses are table notes at the bottom
Part # Application Version Checksum (4) Date (1) Chip (2)
HLN9277A Low band, high band, UHF and 800 Conventional 5 pin 4.00 A800 1987 27C64
HLN5569A Low band, high band, UHF and 800 Conventional 16 pin
This version supports high tier, signaling, and 32 modes and is the most common version found in the non-900 MHz MaxTracs.
5.34 3500 1987 27C256
HLN9435A 800 MHz Trunked 16 mode and conventional 54.03 3FD0 51/92 27C512
HLN9260C MaxTrac 840 (800 MHz) 5 pin 52.07 (unknown) 1987 27C256
HLN9383F Startsite Smartnet Type 2 16 pin V71.25 BEB3 22 / 95 27C512
FRN4007B 900 MHz Trunked V80.08 44F3 51 / 94 27C512
FVN4019A 900 MHz Conventional V30.03 BD00 21 / 98 27C256
FLN6531A 800 MHz Desktrac repeaters (two MaxTrac chassis in a box).
Tx and Rx radios use same firmware (see note 3).
Allows entry of 800 band repeater receiver frequencies.
V31.00 90D0 14 / 95 27C256
5102901S02 Intrac UHF MaxTrac VIL 1.014 (unknown) 1990 27C256
HLN9499B Radius M214 / M216 16 pin (LRA)
This board must be programmed with RADMBL (Radius RSS) and supports 16 modes and channel steering from the 16 pin I/O connector.
21.01 CC00 1987
VLN5443A 99 channel low band MaxTrac (specially made for Ontario Hydro, the electric utility in Ontario, Canada). This firmware requires additional EEPROM to be added to the logic board. The radio also requires a special RSS to program it. S5.35 B100 1991 27C256

  1. The date can be in XX / YY format where XX is the week and YY is the year. For example, 51 / 94 is the 51st week of 1994.
  2. If you find a firmware chip labled with the part number of 27014 it is a house number for a standard 27C256.
  3. The low band, high band and UHF Desktrac repeater uses the standard mobile firmware in their transceivers - only the 800 MHz units need the FLN6531 firmware - which makes sense since the VHF and UHF standard mobile frequency ranges cover the respective repeater input and output sub-bands whereas the 800 mobiles normally cannot receive the 800 repeater input frequencies.
  4. An (unknown) entry means that we don't have that checksum in our notes. If you have it in yours please send it in.

If you find an EPROM with a label reading "Scholer-Johnson", "Scholer-Johnson Inc.", "SJI", "CVT-2-400" that is an aftermarket LTR trunking EPROM designed for the MaxTracs (usually 800 MHz, but occasionally seen on 900 MHz, UHF or even high band). If you find one and want to convert it back to a regular radio you will have to replace the chip with the stock conventional firmware, and then you will have to blank and reinitialize the logic board with MaxTrac Lab. Occasionally you find the stock firmware in an antistatic bag stuck inside the radio but that is extremely rare. If you want to use the radio on an LTR system then you need the Scholer-authored RSS to talk to it (and you will need that anyway to read and save the tuning data before you blank the board). See the article on "Converting a Two, Six or Eight Channel MaxTrac or Radius M100 to 16 or 32 Channels" for information on blanking and reinitializing a board.

Logic Boards:       (You may have to pop the metal shield off the CPU compartment to find the board number)
Used in... Comments
HLN9313A,B 16 All except 900 MHz One of the two 16 pin boards, and the only one used on non-900 MHz radios.
HLN5172A,B 5 All except 900 MHz Normally found in trunking (or ex-trunking) radios. The 16-pin firmware has been sucessfully used in this board to max out the channel capacity and you should be able to program pins 2 and 3 on the five pin connector (normally associated with emergency input and alarm output) for other functions just as if they were pins 9 and 4 on a 16 pin board.
HLN5173A,B 5 All except 900 MHz Normally found in conventional radios. Can have newer firmware installed but has no external EEPROM chip and therefore has limited channels.
HLN5123A,B 5 All except 900 MHz Normally found in conventional radios. This is a masked CPU board (i.e. no EPROM socket) and as such cannot be upgraded with newer firmware and does not have an external EEPROM threfore has limited channels.
FRN5529A,B 16 900 MHz only Trunked or conventional, to change requires changing the firmware chip (use only 900 MHz firmware on 900 MHz logic boards).

RF Boards:
Frequency Range(s) Comments
HLB4099A,B 29.7-36.0 MHz Can be pushed down to amateur radio 10 meters.
HLB4100A 36.0-42.0 MHz Pretty useless for amateur radio except as parts, or as an IF frequency.
HLB4101A 42.0-50.0 MHz Can be moved to 6 meter amateur radio, there is an article on this topic at this web site.
HLD4321B 136-162 MHz Preferred board for 2m amateur radio, CAP, MARS and NOAA weather, but rare.
HLD4322B 146-174 MHz Third best for 2m.
HLD4322C 144-174 MHz Second best for 2m amateur radio, also rare.
HLE4425A, B 403-430 MHz Perfect for 420-430 MHz links and control channels.
???????? 430-450 MHz There is a consistent rumor that a 430-450 MHz board was made for the UK / European market. If anyone can confirm or deny the rumor, we'd like to know.
HLE9310A, B 449-470 MHz Can be stretched downward to cover 440-450, but a 438-470 MHz GM300 is better.
HLF4095B RX 851-870 MHz
TX 806-825 MHz
(800 MHz non-talkaround) marked DUPLX on the board. Useful only in an 800 MHz commercial mobile (i.e. as the user radio in a repeat-only environment).
HLF9122A RX 851-870 MHz
TX 806-825 MHz and
TX 851-870 MHz
(800 MHz talkaround) marked SIMPLEX on the board. This board has a dual range VCO and the talkaround oscillator can be locked on and used as the low side injection on a 900 MHz repeater receiver.
FLF5298A RX 935-941 MHz
TX 896-902 MHz and
TX 935-941 MHz
There is only one 900 MHz board. It has a dual range VCO that can be retuned to allow receive in the 926-928 MHz range and transmit in both the 902-903 range and the 926-928 MHz range.
FLF5543A RX 806-825 MHz
TX 851-870 MHz
Moto made an 800 MHz DeskTrac repeater (L35SUM or L45SUM series). One chassis was the transmitter, and used the HLF9122 board. The other chassis was the receiver, and used the FLF5543A board. This had 815 MHz filters in it in order to receive the 806-825 MHz band. No official manual, available or not, seems to cover it. Unique firmware (FLN6531A) was present in both of the radios to accept the repeater frequency ranges; more details can be found in the firmware table above.

Photos of the 800 MHz HLF4095B "DUPLX" and HLF9122A "SIMPLEX" boards are in the article titled Converting Other 800 MHz MaxTracs to the 900 MHz Ham Band.

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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.