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geekhack Projects => Making Stuff Together! => DIY Discussions ARCHIVE => Topic started by: ricercar on Mon, 21 December 2009, 01:50:48
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The following image displays an open Northgate Ultra 102.
(http://geekhack.org/attachment.php?attachmentid=6574&stc=1&d=1261379225)
Notice the unpopulated top F key row, labeled SF1 through SF12, and the unpopulated spaces above the arrow key cluster between the letters and the numeric keypad, labeled as shown presently.
I'm always bothered by printed circuit boards with unpopulated regions that have silk-screened legends. This one is no exception.
I've tested the unused soldering points and indeed they electrically support a complete second set of F Keys. The unpopulated spaces in the arrow key cluster also have legends, and the electrical contacts bear out this functionality, except the mysterious "OMNI" key doesn't seem to have a normal scan code.
(http://geekhack.org/attachment.php?attachmentid=6575&stc=1&d=1261380584)
The following image displays a Northgate Ultra 101. Notice the U102 silk-screened legends match the respective U101 arrow cluster keys. However, the neighboring U101 keys do not match their U102 counterparts.
(http://geekhack.org/attachment.php?attachmentid=6573&stc=1&d=1261376089)
You can safely ignore the top F key row, as this is not part of the final exam. The only thing halfway interesting about top F key row is the U102 electricals do not support the physical U101 F Key arrangement. This therefore shoots down my hypothesis inspiring this article, that Northgate had only one PCB for all their keyboards.
This lead me to review the bottom of the U102 board. What a surprise. The U102 PCB supports two different electrical key arrangements in the same physical space.
(http://geekhack.org/attachment.php?attachmentid=6576&stc=1&d=1261381622)
Confirmed:
- the blue-marked contacts have electrical support for the U102 key arrangement it shipped with. (like,duh!)
- the red-marked contacts have electrical support for the U101 key arrangement, but are unpopulated.
To do list:
- test the simultaneous use of U101 and 102 keypads, including testing in both NUMLOCK states.
- wire the U101 arrow cluster signals into a harness, to the left, for a left-hand arrow array.
- Find out what the OMNI key does.
I've not actually modded the board yet, but I wanted to publish this before I fell aslee.....
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Cool, I always love finding hidden stuff like this. Have you found out what the omni key is yet? Should be a simple thing to solder a new switch in there, you don't have spare alps keys? It's interesting that they even have holes in the mounting plate for the switches. You'd think they wouldn't bother having cut the holes for the lines that didn't have the switches there.
I guess that tells us a bit how these boards are made. I would guess based on that there's one big die that cuts the sheet-metal for alps boards all at once. They must have thought it would be cheaper to make one die for two configuration of switches.
What's the dvorak writing say?
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The Dvorak writing is my notes on DIP switch settings in case I lose the manual.
I'll post as soon as I have time to research the Omni key.
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Have you found out what the omni key is yet?
I've heard that "omni key" on early models ( those with so-called diamond-shaped cursor control ) worked as a program key in combination with some softwares such as Word Perfect.