Converting an IBM Pingmaster

[SaltyMcSushi]

So I wanted to find some keycap replacements for my pingmaster. It's a bit hard to find keyboards with these same switches. Ultimately, I got two keyboards- a Ti-99/4A and a Commodore 64. The C64 doesn't use these switches, but I was able to get the caps to fit well enough with only a minor amount of mutilation. The Commodore logo key is especially awesome. As for the Ti-99/4A, there were 4 different keyboards made, only one with these switches- luckily I found an ebay posting of the bare keyboard PCB so was able to see the Alps logo in the pictures, but with some research you can also figure out which keyboard are which by looking at minor differences in the keycaps.

I've been playing around with the best layout using these keys, and this is how my board looks at the moment:

IMG_20170517_000922718.jpg (272.42 KiB) Viewed 7180 times

Obviously there's a lot of caps that don't match what the keys do, but it's the look that's what's important!

I have read this and many other threads on this subject, so i am uncertain of the source of what i am about to ask. Does the internal speaker still sound upon key presses or has this now been ironed out?

There's a volume knob on the back of the keyboard to control the sound- including turning it completely off.

[just_add_coffee]

IMG_20170517_000922718.jpg

Obviously there's a lot of caps that don't match what the keys do, but it's the look that's what's important!

A E S T H E T I C S

Very nice, but how in the heck did you get that Return key to fit up there?

[seebart]

The C64 doesn't use these switches, but I was able to get the caps to fit well enough with only a minor amount of mutilation.

Elaborate please!

[SaltyMcSushi]

Very nice, but how in the heck did you get that Return key to fit up there?

The return key has three mounts, and the outer two are perfectly spaced so they can fit on adjacent posts. Unfortunately, the shorter modifier keys- Shift, Control, Restore, and Function- all have two mounts, one on the left and one on the right, which is weird and means I can't fit them in matching spots on the Pingmaster, which are designed for a single central mount.

Elaborate please!

So the SKCC post is T-shaped, but the center of the post also has a square shape to it. This shape prevents usage of pretty much any keycap that's built for a simple cruciform shape.

Alps_SKCC_Green_--_variants_table.jpg (88.22 KiB) Viewed 7133 times

My solution was to grind the inside edges of the Commodore keys so that there's space for the central square.

IMG_20170514_140751768.jpg (88.89 KiB) Viewed 7133 times

[gazza341]

@saltyMcSushi

Looks great mate - nice to know it is possible to change the look and feel, even if it is a bit of a ballache to achieve.
Thanks for the tip about the volume wheel.

I've ordered a db9 - think I'll go with the external solution until I'm happy with the layout - so hope to dive in at some point next week



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[seebart]

Cool thanks.

[just_add_coffee]

My solution was to grind the inside edges of the Commodore keys so that there's space for the central square.

What did you use to grind the inside of the keys with?

[seebart]

My solution was to grind the inside edges of the Commodore keys so that there's space for the central square.

What did you use to grind the inside of the keys with?

Good point. And how long did all this take you?

[SaltyMcSushi]

I used a screwdriver that I got to adjust my mouse, the Torq X10. It's a hex-star shaped thing.



The screwdriver was the perfect size for it- I could stick it into the keycaps so that the nooks in the screwdriver matched with the inner edges of the cap. Then by rotating the screwdriver a bunch of times it wore down those inner edges. Took less than a minute per cap. If you don't wear them down enough, they'll go on crooked.

[just_add_coffee]

Thank you Salty! I asked because I'm still contemplating some way to put SA Jukebox on this board. Cherry MX stems probably have a smaller diameter than the Commodore keys, so I'm thinking I'll have to do more than grind out the center. But learning how people overcame specific issues can prove useful down the road!

[just_add_coffee]

Only adding the resistors alleviated nearly all of the keyboard's quirkiness, e.g., lost keystrokes, lost key assignments, randomly spewing a stream of characters, etc. Even with my 3m USB extension cable.

With the hypothesis that superfluous noise is entering the cable in mind, I decided to salvage part of the original cable, which is protected, and screw the ground lead back in.



So far ... so good!

I still need to figure out how to mount the Teensy to the top portion of the case in order to allow access to the button.

[ohaimark]

Pull up resistors rock.

[Wingklip]

I reckon I might have to put one or two on for my 3178 Model C2 because it seems to not register keys sometimes whilst still in the bios

[SaltyMcSushi]

Thank you Salty! I asked because I'm still contemplating some way to put SA Jukebox on this board. Cherry MX stems probably have a smaller diameter than the Commodore keys, so I'm thinking I'll have to do more than grind out the center. But learning how people overcame specific issues can prove useful down the road!

Glad I could help! Best of luck with it.

I reckon I might have to put one or two on for my 3178 Model C2 because it seems to not register keys sometimes whilst still in the bios

I'm not an expert, but it may have to do with polling rate being too high. Corsair keyboards have a polling rate switch that includes a low-rate BIOS setting for compatibility. IIRC, TMK pretty much polls as fast as the Teensy is able.

[Shean]

Does this fix the problem with having to re-upload the hex file every time you connect the keyboard?

[Shean]

I've found that if you just connect your keyboard and give it like ten seconds before you start using it it works perfectly fine but if you try typing on it immediately after connecting it it starts acting wonky.

[Wingklip]

Thank you Salty! I asked because I'm still contemplating some way to put SA Jukebox on this board. Cherry MX stems probably have a smaller diameter than the Commodore keys, so I'm thinking I'll have to do more than grind out the center. But learning how people overcame specific issues can prove useful down the road!

Glad I could help! Best of luck with it.

I reckon I might have to put one or two on for my 3178 Model C2 because it seems to not register keys sometimes whilst still in the bios

I'm not an expert, but it may have to do with polling rate being too high. Corsair keyboards have a polling rate switch that includes a low-rate BIOS setting for compatibility. IIRC, TMK pretty much polls as fast as the Teensy is able.

I have to plug then unplug it for it to fully register lol

[gazza341]

I started to make my converter today, initially with a pro micro, but then ended up doing it with a teensy 2.0.
I must say, although there is a plethora of information and knowledge to aid this conversion, it is probably overwhelming and can send you down a rabbit hole.
I want to mount my solution internally, when I am happy with the mapping, but for now I am going with the external makeshift version. The first of the photos are of the pro micro solution, but due to my inexperience, I ended up bricking the board (I have now revived it, but more by luck than any of the 'solutions ' out there). I eventually got the pro micro version working with soarers hex, but there was something amiss. When connected to my pc, each keystroke acted like it was permanently depressed. The latter pics are of the teensy solution, which was successful at the first attempt - I used Red's hex from earlier in this thread.


Thanks again to Coffee and Red for their input here - the knowledge and humor helped dismiss a lot of the ambiguity instilled in me from reading other threads on the net.


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[just_add_coffee]

Cool! Another vaporererer!

With the external solution, have you had any issues with the board not responding, randomly firing keys, or any other issues? I'm still experiencing those things, though the 1kohm resistors helped a lot. I plan on trying 22kohm resistors and maybe an inline capacitor going into Vcc later this week, and I'll try the external solution later on a new board.

[gazza341]

TBH, I haven't tested it at length, so I can't really say, but as yet I haven't noticed any of the quirks you report. I'll try giving it a proper testing over the next few days


EDIT: wondered what you were on about re:vaporererer - how could he know?!!! scanned my photos for any clues, but just seen it in the last pic

[gazza341]

Hey Coffee, just a quick sanity check - are you typing with sausage(s) finger(s)?
Are you always plugged into the same pc/USB port?
Is the pc you are plugged into always connected to the mains supply?
I only ask, as I have experienced similar issues this evening, following an in depth test session, but realized it only happened when not plugged into the mains, and differing results depending on which USB port I was hooked up to.
Do tell if any of the above applies.


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[just_add_coffee]

Hey Coffee, just a quick sanity check - are you typing with sausage(s) finger(s)?

Well yes! Is there any other way to type?

Are you always plugged into the same pc/USB port?

Yes. I'm currently using a USB extension.

Is the pc you are plugged into always connected to the mains supply?

Don't know what you mean here.

Here's a better description of what I'm experiencing:
1) Watching something on Netflix or HBO ... I press the key to turn up the volume. Nothing happens. I press it again. Nothing. I then press it five or six times in rapid succession. THEN the volume window pops up and the volume increases.

2) I move the cursor to the URL bar in the browser. Immediately, I get "ddddddddddddddddddd ... " until I click on something else, push the Teensy button, or unplug/plug-in the keyboard.

The pull-up resistors greatly reduced the frequency of these issues, but they haven't gone away entirely.

The mystery is a-foot!

[gazza341]

Just to clarify.
I was connected to a laptop which was running on battery (not plugged into the mains power). I only experienced the issue you described when the battery started to dwindle.
So, I believe it may be power related - the USB port not delivering enough juice to power the keyboard/teensy

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[just_add_coffee]

Just to clarify.
I was connected to a laptop which was running on battery (not plugged into the mains power). I only experienced the issue you described when the battery started to dwindle.
So, I believe it may be power related - the USB port not delivering enough juice to power the keyboard/teensy

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I'm getting 4.98V at Vcc. And I've never had these issues on any other keyboard. Same computer, same USB extension.

Installed the 22kohm resistors. It's too early to tell, but so far so good.

My job tonight is to see if the missus will let me get an oscilloscope.

[gazza341]

My job tonight is to see if the missus will let me get an oscilloscope.

https://www.ebay.co.uk/p/?iid=291463433 ... t=0&chn=ps
only, don't use the usb extension to connect it

[just_add_coffee]

only, don't use the usb extension to connect it

I really don't think the USB is the problem.

Which absolutely means that the USB is the problem.

[hasu]

I think without decent pullups the converter won't work in some severe situations, or it is just lucky that it appears to work somehow.

just_add_coffee,
you replaced 1kohm resisters with 22kohm? It may be too weak, use 1kohm. if you still have issue with 1kohm, I would doubt your soldering. Seeing pic in this post and your joints don't seem to be reliable, to be honest. (Don't get me wrong, I'm not in the mood for offense yet ) Also check controller joints assuming that you desoldered and resoldered it before.
workshop-f7/converting-an-ibm-pingmaste ... ml#p371660

gazza341,
Don't pull-up resisters help? assming you have no pull-ups.

[just_add_coffee]

I think without decent pullups the converter won't work in some severe situations, or it is just lucky that it appears to work somehow.

just_add_coffee,
you replaced 1kohm resisters with 22kohm? It may be too weak, use 1kohm. if you still have issue with 1kohm, I would doubt your soldering. Seeing pic in this post and your joints don't seem to be reliable, to be honest. (Don't get me wrong, I'm not in the mood for offense yet ) Also check controller joints assuming that you desoldered and resoldered it before.
workshop-f7/converting-an-ibm-pingmaste ... ml#p371660

My soldering should always be doubted. I didn't take a pic this time, but it's a bit better than before and I'm slowly improving overall. Hopefully I'll get my act together before the Ergodox Infinity on Massdrop gets here.

Regarding resistors, don't 22,000 ohm resistors provide more resistance than 1,000 ohm resistors? Why would allowing more current between Vcc, and Data and Clock be better?

[hasu]

Lower value resister(= stronger pullup) improves rise time of the signals.

See this links also. Two members with great skills explained and recommeded 1kohm there.
https://github.com/tmk/tmk_keyboard/issues/71

[Wingklip]

I think without decent pullups the converter won't work in some severe situations, or it is just lucky that it appears to work somehow.

just_add_coffee,
you replaced 1kohm resisters with 22kohm? It may be too weak, use 1kohm. if you still have issue with 1kohm, I would doubt your soldering. Seeing pic in this post and your joints don't seem to be reliable, to be honest. (Don't get me wrong, I'm not in the mood for offense yet ) Also check controller joints assuming that you desoldered and resoldered it before.
workshop-f7/converting-an-ibm-pingmaste ... ml#p371660

My soldering should always be doubted. I didn't take a pic this time, but it's a bit better than before and I'm slowly improving overall. Hopefully I'll get my act together before the Ergodox Infinity on Massdrop gets here.

Regarding resistors, don't 22,000 ohm resistors provide more resistance than 1,000 ohm resistors? Why would allowing more current between Vcc, and Data and Clock be better?

It might be safe to say that the controller itself has some issue with soldering or something. Did you make sure that the grounding wire was attached?