Zenith ZFA-138-42 Mods + Video with Typing Sounds

[Hypersphere]

The Zenith ZFA-138-42 keyboard is similar to the Zenith Z-150, but the former has been lightened up a bit for use in a "portable" computer. The ZFA-138-42 resembles the ZFA-161-416 that is cataloged in the DT wiki:

wiki/Zenith_ZFA-161-416

Some features of the ZFA-138-42:

+ Black Zenith logo badge.
+ Simplified flat top case (compared to the Z-150). Has nubs and latches for securing it to the luggable computer.
+ Plastic rather than steel back case.
+ Steel plate.
+ Alps SKCL Green switches (linear).
+ Alps wire stabilizers on the spacebar and other wide keys.
+ Dye-sublimated PBT keycaps (spacebar is ABS). White alphanumeric keys; gray modifiers.
+ Modified XT layout.
+ AT-type connector, but proprietary protcol.

Modifications:

+ Hybridized switches from linear to tactile/clicky with tops, sliders, springs, and click leaves from SKCM Blue Alps.
+ Cleaned Blue Alps parts using an ultrasonic cleaner. Lubed the sliders with Dupont dry teflon.
+ Installed an internal Orihalcon/Soarer converter.
+ Remapped keys to a HHKB-esque layout.
+ Installed a micro-USB connector.
+ Closed the opening for the former connector with a US 25-cent coin (perfect fit!).
+ Lined the case with "art foam".
+ Replaced modifier caps with caps from Matias black blanks, Tai Hao red Dolch, and Tai Hao black.
+ Installed a Matias Quiet slider in the Spacebar switch.
+ Applied self-adhesive thin foam strips on the top plate where the spacebar stabilizer inserts make contact.

Pics:

Top left - Zenith badge

zfa-left1ad2c125.jpg (97.38 KiB) Viewed 1537 times

Right side

zfa_rt_ad1bc125.jpg (110.37 KiB) Viewed 1537 times

Hybrid switch and underside of dye-sub PBT cap

zfa_Blue1ad1c125.jpg (100.91 KiB) Viewed 1537 times

Micro-USB connector

zfa-usb1ad2c125.jpg (54.15 KiB) Viewed 1537 times

Former connector opening blocked with US 25-cent coin

zfa_quarter_ad1bc125.jpg (57.65 KiB) Viewed 1537 times

Bottom case showing a flip-out foot and latch

zfa_latch1ad2c125.jpg (70.81 KiB) Viewed 1537 times

Waveform of typing sounds (dB vs time)

zfa-138-42-gblue-db.PNG (27.33 KiB) Viewed 1537 times

Typing sequence: 3 times each of the following sequences:

097
oii
;lk
/.,
\
Return
Right Shift
NumPad Insert
Spacebar
Thumping finger on top-center case

The typing sounds and feel on this modified Zenith remind me of typing on a Leading Edge DC-2014. I prefer the looks of the Zenith.

Video with typing sounds

[Hypersphere]

The problems I was having with missed or repeated keypresses was not due to bad switches after all. It was the Soarer's converter. It turns out that Soarer's does not work completely with the Zenith Z-150 type of keyboard. I got it working perfectly using a Teensy and Hasu's xt_usb hex file that I customized using his TMK Editor.

Details have been posted on another DT thread:

keyboards-f2/xt-zenith-z-150-converter-t12972-90.html#p432296