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  Removing the Secure Board from a
Digital-Capable MSF5000 Station

By Robert W. Meister WA1MIK
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A while ago, someone on the MSF5000 YahooGroup posted the following question:

>I recently bought a CXB, UHF station,
>that has a Secure board installed. Can
>someone give me the information as to
>how to un-install it? Thanks.

Sure. Read on.


The Secure board is only available on the digital-capable stations. When not in use, the Secure board is (supposed to be) transparent to incoming and outgoing audio in the station unless the board has security keys and has been enabled. Audio does pass through the board, however, and it's one more place where something could go wrong. If you're never going to use it, why even keep it there? You may be able to sell the board to a commercial establishment to recoup some of the money you paid to buy the station in the first place. Like all old Motorola gear, MSF5000s are now discontinued and parts may not be available.

There are three things you need to do to remove it, and they must be done in this order:

  1. Disable the Secure board in software via RSS.
  2. Disconnect and optionally physically remove the Secure board.
  3. Change a shorting jumper on the Secure-capable Station Control Board (SSCB).

IMPORTANT: You MUST disable the Secure board in the station's code plug before physically disconnecting the board from the station. If the code plug data indicates a Secure board is present, RSS will try to read that part of the code plug from the station, and with no board there, it will either hang or fail. You may not be able to get past this problem without configuring a new code plug with the proper board configuration settings. Similarly, if you try to write a code plug to the station and a board is enabled but missing, RSS may hang or fail.

Software Changes:

  1. With the station running, connect a computer and RIB to it and read the code plug with RSS (F3, F2). Save it to disk with F7 (just to be safe). Press F10 to return to the main menu.
  2. At the main menu, press F4 (Change/View code plug Data), then F8 (Station Model/Options). Press Page Down to get to page 02 of 02, and the second item should be "SECURE Equipped: ENABLED". Press TAB to get to this field, then press the Down Arrow key to change it to "DISABLED". Press F10 to return to the main menu. This will also delete any other Secure board settings; they can not be restored unless you load the original code plug you saved in step 1.
  3. Back at the main menu, write the code plug out to the station (F3, F8). Save the code plug at this point if you want to (F7).

When the station reboots at the conclusion of step 3 above, you may or may not get an error related to the Secure board. It can be safely ignored at this point.

Hardware Removal:

  1. Unplug the station's AC and DC power cables.
  2. Pull the RF tray out and raise the control tray up to the service position.
  3. Disconnect the Secure board's flat cable going to the SSCB.
  4. Disconnect the key loader cable, if present, and remove the cable entirely.
  5. Carefully pop the Secure board off the four plastic mounting studs on the SSCB (they're like a ball-and-socket joint) by putting your fingers between the two boards and prying the Secure board off the studs.
  6. Slide the board backwards just a bit so the LEDs clear the front panel, and out it comes.

Jumper Settings:

But wait, there's more! (I just love when they say that on TV.) You still have to move a jumper to let the station operate without the Secure board.

The High Speed Ring-buffer (HSR) signal is sent to all boards in the station. It is the responsibility of the Trunked Tone Remote Control (TTRC) board and the Secure board to pass this HSR signal back to the microprocessor on the SSCB. If a board is missing or unplugged, the signal will not be returned and the station will either hang up or generate errors during programming or normal operation. To deal with this condition, a shorting jumper is used to route the signal back to the SSCB when a board isn't present. JU1 does this for the TTRC; JU2 does this for the Secure board.

On the SSCB, between the TTRC and Secure board connectors up near the top of the board, there are two well-labeled jumpers: JU1 and JU2. Both of these jumpers are horizontally oriented. JU2 (the front-most jumper) needs to be put in the rear position (middle and rear pins shorted) to route a signal around the now-missing Secure board. The middle and front pins are shorted with this jumper if a board IS present, the middle and rear pins are shorted with this jumper if a board is NOT present. You can see these jumpers - the yellow blocks above the "Secure Board Cable Socket" - if you look carefully at the upper left corner of the digital-capable SSCB photo below (click on it for a larger view):

Here's a more detailed view of those two jumpers, shown in their "Normal" positions as indicated by the white bar above each one: TTRC Present, Secure Not Present. Move JU1 to the left two pins if removing the TTRC. Move JU2 to the right two pins if installing the Secure board. If the jumper is in the right-most two pins, the board is present. If the jumper is in the left-most two pins, the board is not present. In this photo, the left side is towards the rear of the station when viewing the SSCB in its raised service position. (Click on it for a larger view.)

Close the control tray and restore the RF tray to its normal position. Power the station up; you should not get any error codes, unless there were some present before you started this procedure.

Other Notes:

These same major steps, performed in reverse order, can be used to install a Secure board: change JU2, install the board (and key loader cable), then enable the option with RSS. If you disable the Secure board in RSS, it will completely remove the Secure portion of the code plug. You can not just re-enable the Secure board again in the future. You must instead start with a default code plug and build it back up to what you need.

You can remove or install a TTRC board the same way: changing the "TTRC Equipped" field in RSS instead of the "Secure Equipped" field, and flipping JU1 on the SSCB instead of JU2. If you disable the TTRC in RSS, it will completely remove the TTRC portion of the code plug. You can not just re-enable the TTRC again in the future. You must instead start with a default code plug and build it back up to what you need. You should leave the disconnected TTRC in the control tray.

These Directions Weren't Followed; Now What?

You've got a station that previously had a Secure board and someone physically removed it without disabling it in RSS first, or you've got an SSCB from a station that had a Secure board and it wasn't disabled before being removed. Errors are displayed during the power-on self-tests, and you can't read the code plug because of the missing Secure board. What can you do?

Neither RSS nor the station will let you grab any portion of the code plug unless it's all present and available. Since the Secure board isn't there, RSS can't read that portion and you're completely out of luck. All you can do is start fresh with one of the default code plugs that came with the RSS package. Configure it for your station, making sure you have enabled only those boards that are present in the system (TTRC, Secure, etc), and write that to the station. After the station reboots, the errors related to the missing Secure board will be gone and you can continue to refine your code plug. Yes, you'll lose whatever was programmed into the station, but once you get it running, you can load your saved copy of the code plug from disk (you DID save it last time you wrote it to the station, didn't you), make sure you've disabled the board(s) that are no longer in your system, write that code plug to the station, and you should be back in business.


Information for this procedure was taken from the Motorola Field Programmer (RSS) User's Guide 6881125E68, and UHF Digital-Capable Service Manual 6881092E80, as well as examination of a CXB UHF station.

Contact Information:

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

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This page was created in June 2006.

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.