Epson QX-10 Keyboard NKRO USB conversion (Fujitsu 2nd Gen Leafsprings)

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Sangdrax

30 Mar 2019, 11:59

Special thanks to snacks for his previous work on this stuff. It sure helped me get up off my ass and get this done.

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Here's his matrix trace with a few additions. One is to have all the numbers on the column and row connects for each switch so you don't have to hammer it out from the firmware. There was a minor miss on the Row 11 stuff so look close to where the 11/12 break is there. The numbers show it but it's different from the original colors.

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I tried to use as much of the existing traces as I could. Almost half the rows have only one switch connected so I was even able to put single diodes in the old diode slots. Two things just would not desolder though and trying to force it just wound up with a couple scorched spots. Boy, that's embarrassing. Any proper electronics guy would tear me a new one for that popcorning around the old jack connect.

Otherwise, everything else turned out well. Only screwup was me not paying attention and accidentally wiring the keypad enter to the column instead of the row. Two minute fix but you can see it in the pic.

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View from the top.

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Wiring up the LED's in double for the pin current limits actually worked out just fine. You can't hardly see the brightness difference.

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And all nice and clean. I love the switches on this thing, definitely in my top 3 linear switches.

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Finally, QMK firmware for it. Works fine if you use the column and row numbers from the first pic. Layout file included for your own binding. https://www.mediafire.com/file/845k3yi2 ... e.zip/file
Last edited by Sangdrax on 03 Apr 2019, 00:22, edited 1 time in total.

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OldIsNew

02 Apr 2019, 02:53

Nice!

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snacksthecat
✶✶✶✶

14 May 2019, 00:32

Woah I missed this! Nice write up!

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Sangdrax

14 May 2019, 03:25

Thanks guys. Been using her as a daily driver and she's going strong. I did tweak the key assignments a bit though. Even did some silly stuff like alt code macros so the ½ ¼ key outputs that for real now in the first layer.

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kralcifer

25 May 2020, 21:28

I need to convert my similar keyboard, an Epson Q703D-AA. It uses brother dome and foil for switches. I believe I need the same conversion and you and snacksthecat because when I read the QX-10 manual it referred to the same NEC D8049HC and Toshiba T6930KB chips that I have on my PCB.

First I wanted to share that I think I found some extra manuals in case you guys needed them. Sorry if you already mentioned these:

http://electrickery.xs4all.nl/comp/qx10/doc/index.html

Some of the pdfs are image scans so no text searching, you have to read it! haha.

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kralcifer

25 May 2020, 21:31

I've never done a conversion yet. I'm not seeing any mentions of Epson in Soarer/Hasu/Haata so far but still looking.

Why did you guys have to trace the PCB like that? I thought I should be able to look at the values coming out of the 8-pin DIN and convert there where the cable comes out. What am I missing?

Thanks,

Kralcifer

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DMA

25 May 2020, 23:28

kralcifer wrote:
25 May 2020, 21:31
I've never done a conversion yet. I'm not seeing any mentions of Epson in Soarer/Hasu/Haata so far but still looking.
Are sure it's foil? Leaf spring is a contact switch, * and foil is usually capacitive (look at Sangdrax's other posts for his foam-and-foil conversion adventures). It's pretty straightforward - the foil from antistatic bags works pretty well. It might get Creative if domes disintegrated or otherwise lost elasticity. Sun type 5c _might_ serve as a source of domes (not a legal advice).
kralcifer wrote:
25 May 2020, 21:31
Why did you guys have to trace the PCB like that? I thought I should be able to look at the values coming out of the 8-pin DIN and convert there where the cable comes out. What am I missing?
There are two kinds of conversions:
a) protocol converter - a box providing the power and pretending to be the host for the keyboard.
b) MCU replacement (very rare) - driving the original electronics from a modern MCU
c) total conversion: only using the switches and PCB, driving everything from the modern MCU.

With your raytheon I had to d) cut the matrix into separate switches and handwire them, because it's either PCB water damage or long sense traces running in parallel, but keypresses light up adjacent rows - some up to 4. I would know in couple of hours if it worked. It was surprisingly calming experience rewiring, even though it took two full days (well, OK, I spent half a day making jigs for mah new stripmaster, but still)

Anyway. PCB tracing is a dead giveaway for c)
People usually resort to c) when a) is not feasible (Usually because of not enough modifiers - old keyboard designers liked to use keys (or the protocol) wihch only emit a pulse when pressed).

User avatar
kralcifer

26 May 2020, 03:54

Thanks for the reply DMA. Hope you won't mind chatting on my other thread about my Epson model. I'll repost your comment over there.

And let's see a post about your new stripmaster and jigs!

And thanks for not giving up on my Raytheon! I appreciate it. I'm trying to build up my endurance to your level for tackling hard problems!

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kralcifer

28 May 2020, 04:45

Sorry I spammed your topic Sangdrax. I respect the work you and snacksthecat do and did. I don't think I read closely enough that you already had found what you needed from documents before I spammed some pics and another link. I wish I could delete my comments from your topic so it would be cleaned up but I don't see a delete and not sure if emptying out posts would look silly. My apologies.

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