Adding a physical reset switch to the NEC MobilePro 780/790

CESD-H-0053

Applies To:

  • NEC MobilePro 780
  • NEC MobilePro 790

Overview:

This article discusses the electrical steps required to add a physical soft-reset swtich onto the motherboard of the MobilePro 780 or MobilePro 790 so as to allow you to soft reset (reboot) the device without flipping it over.


More Info:

I hate having to flip my Mobilepro upside down in order to reset the device. The HP people got it right with the Jornada 720…their reset is on top and easy to get to.

Well here is a simple solution that you can use on any MP780 or 790.

If you are like me, you rarely use the scroll wheel. I prefer to use the cursor keys to scroll. But NEC included a scroll wheel with the 780 and 790 that has 3 functions. Scroll up, scroll down, and push to select.

I am willing to give up my push to select in order to have an easy reset switch right on top.

 

To perform this mod, you will need the following materials:

  1. The tools to disassemble your MobilePro 780/790 including clockmakers philips head screwdrivers
  2. A soldering iron, solder, and some electrical insulation tape
  3. A length of small wire, about two strands 8" (21cm) in length

The job is really simple and here is what you need to do.

 

Steps

  1. Disassemble your Mobilepro and remove the motherboard
  2. Locate the contact points where the reset switch is mounted on the bottom of the motherboard. You can see the contact points in the following pictureContact points
  1. Solder two wires to these contact points, each wire about 8 inches long. You can see how I did it in the next pictureSolder points
  1. Reinstall the motherboard in the bottom case half. There should be ample room to fit the wires around the edge of the motherboard. In the next picture you can see the two white wires. I taped them to the top of the motherboard so they would lay flat
    Wire runs
  1. If you wanted to be really fancy, you would solder the wires to some type of 2-wire quick connector so that if you ever disassembled it again, it would be easy to separate the keyboard from the bottom half without having to figure out how to maneuver without cutting the wires and reconnecting them again.

    If you are lazy however, you will just solder the wires to scroll wires harness…which is what I did.

    The following picture shows which wires to use:
    Wiring diagram photo

    You need to use the black wire and the green wire. One connects to each of the two wires I added earlier. The best thing to do is simply cut the green wire near the connector and solder it to one of the white wires. You can do the same with the black wire, however, if you cut it, you lose the scroll up and down function of the scroll wheel. If you just connect one of the white wires to the back wire, then you will retain the scroll function of the wheel.

    That’s it…reassemble and the next time you need to reset…push the scroll button!

Acknowledgements

With thanks to Rich Hawley for writing this article and exploring the electrical engineering steps required to implement the modification.