Recently, I bought a Northgate Omnikey 101 ANSI white Alps keyboard from "Northgate Bob". He selected the best one he had available. It is not NIB/NOS, but reasonably pristine. It was very clean and had only a few small spots of corrosion on the plate.
After removing the keycaps and case, I cleaned the plate and the outside of the switch tops using dry cotton swabs, taking care not to leave any cotton lint behind. After soaking the case in detergent overnight, rinsing with water, rinsing with 70% isopropyl alcohol, and drying overnight, I painted the top shell burgundy red with several light coats of Duplicolor vinyl & fabric coating. I put the painted case aside for 8 days before reassembling the keyboard. I did not paint the bottom metal pan, but I used mineral spirits followed by 70% isopropyl alcohol to remove the glue from the inside that held the ferrite core in place.
Next, I installed an internal Orihalcon/Soarer USB Converter and panel-mount micro-USB connector. I replaced the solid ferrite core with a hinged ferrite core that has a 5 mm opering. I placed a piece of 1/16" thick "art foam" cut to size between the PCB and bottom pan. I then installed new keycaps. For the top row, number row except Backquote and Backspace, Nav Island, and all but the number keys on the Numpad, I used WoB Tai-Hao ABS doubleshots. Alphas and NumPad numbers = dye-sub PBT from an SGI Granite. All others = blank black ABS from Matias. Per my standard procedure, I've programmed the board with a HHKB-like layout.
For the spacebar, I used a stabilizer, clips, and inserts from Matias. I removed the stock shock pads because they are in the wrong position for the Matias spacebar and they interfere with the Matias stabilzer wire. I put new shock pads on the plate where the stabilizer inserts hit the plate, using self-adhesive 0.15 mm polyurethane foam. To deaden the spacebar, I put small rectangles of 0.5 mm self-adhesive foam rubber inside the space bar. To quieten the spacebar switch, I installed a new slider from a Matias Quiet switch, but I kept the white Alps click leaf. All this results in a very quiet spacebar with no rattle.
I kept everything else intact. This time, I did not open and clean the switches (except for doing a slider swap on the Spacebar switch).
The keyboard is smooth with crisp tactility and just the right amount of clickiness for me. The switches feel consistent across the board. I have not noticed suppressed clicks, return-stroke clicks, chattering, or binding. The board provides a splendid typing experience that compares favorably with my all-time favorite keyboards (these include my IBM XT, silenced and lubed RF87UB55, silenced and lubed HHKB Pro 2, Leading Edge DC-3014 blue Alps, and cleaned and lubed Northgate Omnikey 101 ANSI white Alps).
As with my previous Omni 101, I found that I could not use the dye-sub PBT caps from an IBM 5140 (brown Alps). These caps have worked well on several other Alps and Matias-switch keyboards, but they do not bottom-out consistently on the Omni 101 keyboards. This is why I ended up using caps from an SGI Granite, even though I am not fond of the Italic font. Does anyone have any idea why the IBM caps do not work well on the Omnikey 101 boards?
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@MandrewDavis: Let us know how you get on with click-modding your Zenith. I have a Z-150 with Green Alps and a 163-73 with Yellow Alps that I am considering click-modding. It's nice that the procedure is reversible. Does this mod require pine switch tops, or is that just your preference? That is, would it work with the bamboo version of white Alps tops?