Another C1P build

[HOWARDHB]

Let me begin by thanking everyone whom has contributed to this fine resource, for all things OSI !

After years of wishing that I could lay my hands on a C1P, I am finally able to re-create one!

Here follows my journey....

[HOWARDHB]

OK, so all parts have been ordered, some have arrived already...

While waiting, I agonised over the un-availability of a "latching" CAPS LOCK key-board switch...
This really bothered me, as I just didn't want to add a separate switch...
I'm going for an accurate a replica as possible, so, what to do?

I found a 3D cad model of the Cherry MX key-board switch, and upon investigation, it occurred to me, that maybe, just maybe, a suitably small, latching, push button could fit INSIDE the the MX switch...

My search for a tiny latching push-button turned up JUST ONE candidate that would possibly fit inside...
The switch part# is: PB-22E60

PB-22E60.jpg (101.9 KiB) Viewed 25990 times

Look how tiny it is:

tiny.jpg (305.7 KiB) Viewed 25988 times

Once I had 3D modeled that tiny switch in SolidWorks, it was quite apparent that it could be done!
Here is an exploded view of my CAD rendering (Solidworks) of the Cherry MX with the switch installed...

MY LATCHING MX.JPG (175.65 KiB) Viewed 25990 times

It was pretty darn fiddly to say the least!

After removing the existing MX copper contacts inside, I could machine away (Dremel) superflous plastic in the base of the switch.
I had to bend & shape the legs of the tiny little switch to suit the MX switch solder pin positions.
(I had to solder a leg extension onto one leg of the tiny switch, and cut off the four superflous legs)
Once I was happy with the position of the little switch, the MX switch cover clipped closed nicely.

I now have a LATCHING CAPS-LOCK switch !


Here is the assembly progress:

1ST STEPS.jpg (750.73 KiB) Viewed 25990 times

I haven't yet managed to find key-caps, so I'm leaning towards 3D printing them as well as the space-bar stabiliser...
We'll see...

Cheers for now.

H.

[ronin47]

Do you think it would be possible to take an exisiting Cherry MX (I have spares) and retrofit that switch internally?

If so I might have to give it a go.

Also, with regards to keycaps, have you tried PMing Dave? I got mine from him, he may have sets left.

[HOWARDHB]

Go for it!

The Cherry MX switch that I've used is : part# MX1A-11NW-1 (HyperGlide Black )
Ordered from Amazon, cost $53 (including shipping) for 70 switches: so I have some spares.

Subsequently I found and ordered another 100 switches from EBAY for $15, shipping INCLUDED !

Doh!

cherry mx 1.jpg (63.38 KiB) Viewed 25980 times

I will make TWO more "latching" switches and populate the remaing two KlyBall 600D PCB's (that I've had manufactured locally) with these...

Attached is a CAD ( .step) file that you could use to "see" what I've done.

I have messaged Dave, awaiting his reply!

H.

CHERRY MX KEYSWITCH.zip

(773.49 KiB) Downloaded 307 times

[HOWARDHB]

Attached is a 3D PDF model that Adobe can open...

H.

MOD KEYSWITCH.pdf

(301 KiB) Downloaded 324 times

[ronin47]

Thanks

I got my 'Cherry MX' switches from eBay for £15 and they might be fake, but they are fine

I'll see if I can get my hands on some of the latching switches and do some experimenting as I have lots of spare switches (30 plus I think).

[HOWARDHB]

Progress!

Key-switches and all IC sockets installed.

Soldering without a solder-mask is challenging!

I photographed the solder-side and reviewd my work by zooming right in and inspecting...
I found 4 solder bridges

PROGRESS 6 JUNE 2024.jpg (789.98 KiB) Viewed 25689 times

Although there is still a LOT to do, just holding the board in its current state, I'm having distinct nostalgia feelings already

I purchased an old cassette tape recorder, and, after replacing its belt with my own 3D printed one, have "recorded" a few programs onto tape (by playing .wav files on my phone!), ready to test the ACIA... Just hearing 300 baud AFSK for the first time since 1985 brought a huge smile... marvelous!

H.

[Thomas]

What a beauty

[ronin47]

Progress!

Key-switches and all IC sockets installed.

Soldering without a solder-mask is challenging!

I photographed the solder-side and reviewd my work by zooming right in and inspecting...
I found 4 solder bridges

PROGRESS 6 JUNE 2024.png

Although there is still a LOT to do, just holding the board in its current state, I'm having distinct nostalgia feelings already

I purchased an old cassette tape recorder, and, after replacing its belt with my own 3D printed one, have "recorded" a few programs onto tape (by playing .wav files on my phone!), ready to test the ACIA... Just hearing 300 baud AFSK for the first time since 1985 brought a huge smile... marvelous!

H.

Looking good

I've not been able to source a PB-22E60 just yet, but I am still trying. Most places charge stupid amounts for shipping and one or two switches could work out expensive that way.

I must confess soldering without a solder-mask, wasn't a problem for me, though I certainly had my fair share of other issues.

Just make sure U29 is a 74LS93 and not a 74LS92 as per the BoM. The 92 doesn't work...

My other issues and gotchas are here: viewtopic.php?p=5552#p5552

Hoping they may help you out.

As for the keys, did you try PMing Dave at all to see if he had any kits left?

[HOWARDHB]

I have messaged Dave, again...

I have read your build thread, so, thanks for the heads-up!

H.