UPGRADING A PortMaster  11 (TM)

Updated: August 26, 1999
Written by: Jake Messinger (jake@ams.com)
 

Although you cannot upgrade the ComOS (TM) on a PM-11, you can perform a hardware upgrade which will allow faster routing and faster serial communications with no comm overruns. The standard PM-11 can handle only 38400 on ALL ports. If you set it to 57600 and there is heavy usage, you will get comm overruns and disconnects.
 

Items you will need to purchase or have on-hand:

  • Get a 386-25 or better motherboard with 1 meg of ram or better. You need to make sure that it's holes line up with the CURRENT motherboard and that it has slots in the appropriate areas. If it has an on-board battery, it MIGHT interfere with the lower right db 25 connector. You may have to reverse the connector or remove that battery and use an external battery pack. Most old 386 boards are capable of using a battery pack which uses 4 aa batteries. AMD bios works best. If possible get a board with a FLOPPY CONTROLLER BUILT IN!!!!!

If the board does NOT have a floppy controller:

  1. Get a floppy controller (or a multi IO with everything ELSE disabled) You MUST remove the bracket and any external connectors from the card. That is why it is best to use a floppy or floppy/ide ONLY card and not a multi IO card. If it has external connectors, then you will have to UNSOLDER them so that the card will fit in the case (or cut holes in the case!) Its better to get a motherboard with built-in IO.
  2. Get an AT power supply. You will be disassembling it.

To prepare the new board:

  1. Put the 386 on a test bench and set it so it does not have installed a keyboard or video or hard drives, set drive A as a 720 k floppy. 
  2. If you want to test the setup before you install it, put a monochrome video card on the board, connect a floppy drive (and controller if necessary) place the Ethernet and the serial port cards on the motherboard. Connect a monitor to the video port. Insert the diskette from a working PM-11. Boot the system. It should say "10 serial ports found" after 30 seconds if the system is working. Connect an Ethernet cable to the Ethernet card and see if you can ping the PortMaster from another machine on your network.

To install:

  1. Open the PM 11. 
  2. Remove the floppy drive bracket assembly and the cable.
  3. Remove the FAN.
  4. Remove ALL the cards. Make note of the orientation of the ribbon connectors and WHICH 5 port serial card was for the first 5 ports. Mark them 1 and 2 if necessary.
  5. You will need to remove the screws and nuts from the parallel port and the Ethernet card, AND the screws from the motherboard (you might have to remove the fan to get to one), and then slide the motherboard forward a bit to get the ethernet barrel out! 
  6. Remove the motherboard
  7. Remove the POWER SUPPLY  board! You wont be using it! 


    8. The case should be completely empty at this point except for the power switch and power connector, and the 10 serial ports and ribbon cables.

  8. Remove the power supply board and fan from the AT power supply. If soldered, unsolder the 2 power connectors from the power supply. We will use the OLD connector and power switch. 

How to connect the OLD switch and connector to the new power supply:

  1. To facilitate the conversion, I would first closely study the relationship of the switch, the power connector and the old xt power supply BEFORE you removed them!
  2. We are concerned with 2 wires; One white wire connected to the power supply board. It should be labeled "N" on the board. And another black or blue wire going to the board labeled "L". If necessary, you may need to solder new, longer wires to the board to reach all the way to the switch. I usually take the wires in the harness from the new power supply that were intended for the NEW switch and use those. Run the N wire directly to the POWER CONNECTOR, The connector should have an N next to one of the prongs. Either solder it or use a spade connector. Run the OTHER wire from the L to the center terminal on the OLD power switch, then run the short wire from the "closer to the center" terminal to the L terminal on the power connector. So NOW N is directly connected to the POWER, and L is switched. 
  3. Attach the AT power supply board where the old power supply was. If the holes don't line up, then you have 2 alternatives. If possible, drill holes so that they DO line up. If that is NOT possible, put tape or other insulating material over the upper left, lower left and lower right standoff and use ONLY  the upper right standoff to attach the AT power supply board. Let the edge of the board rest on the bottom of the case. 
  4. Make sure you have the power supply wired as described above. N to the connector, L to the switch and a small wire from the switch to the L on the connector. Also, make sure that the center GROUND wire from the power connector is REATTACHED somewhere on the case. Originally it is held by a nut to one of the connector screws
  5. Install the 386 motherboard and the Ethernet card simultaneously so that you can slide the Ethernet barrel connector back through the hole. Put in the parallel port card at the same time, too. Then you can screw down the 386 board. You only need 2 screws to hold the board in place. 
  6. If the board has a floppy controller on it, install the floppy cable. If not...
  7. Install the floppy controller with its bracket removed and the 2 serial port cards. It doesn't matter which slots as long as the ribbon cables can reach the connectors. Try to place them so that you can use the "bar" that came in the old unit that helps hold the cards in place.
  8. Connect the power connectors to the board. The black wires go to the inside. 
  9. Reinstall the floppy drive and connect it's power amd floppy cable.
  10. Bundle up all the other power connectors and tie them or tape them out of the way away from the power supply or motherboard.
  11. Test the unit. Make sure the fan comes on. You no longer have the LED unless you want to cut the old one off the old power supply assembly and connect it to the fan wires. In my view, the fan coming ON does the same thing as an LED.
  12. Make sure you get a connection on all 10 ports. If not, then you need to make sure that they are physically connected, and also make sure that OTHER IO on the motherboard or controller card you used is DISABLED!
  • The unit should work just as before only much faster. You should get 1.7 ms ping times as opposed to 6 or more ms. You should be able to operate all 10 ports at 57600 with no comm overruns. Telnetting and resetting options should operate faster as well.

Things that do NOT work: 

  1. You cannot set the ports to 11520 due to a bug in ComOS 2.4.
  2. You cannot use a 16 bit Ethernet card. ComOS can only talk to an 8 bit Ethernet card. If you want twisted pair, get a TP transceiver for from an electronics house.
  3. You cannot boot it from a hard drive. The formatting of the 720 k diskette is proprietary.
  4. You cannot upgrade to a higher ComOS. The higher OS's come on FLASH ROMS and do NOT support the 5 port serial cards.