CM Quickfire Rapid resurrection: a long planning needed!

[umberts]

Hello there!

I'm currently thinking of resurrecting my gateway drug into this hobby: my first Coolermaster Quickfire Rapid.
It has a nice soft rubber case, sturdy plate (which only supports ISO unfortunately but we shall make it work) and it has a faulty PCB. I took the switches and used them in my first custom keyboard, a 3D printed Whitefox, so it stood unused without switches for years.



I'm planning to fix it by doing a handwired build, no PCB, I’m currently indecisive about the MCU.

Due to the way that this case was built (and intended to be used with the included PCB) in order to open it in case something goes wrong I have to attach the MCU to the plate and use the daughterboard included to latch on, that way when it opens I just have to unplug the cables and I can proceed to open the whole thing.

VIDEO OF MECHANISM, UPSIDE DOWN

The only place that I have to do so is here, where there used do be a piece of PCB that I won’t be needing anymore.



Is a little more than 2 cm of width and a little more than 5cm of lenght in the free space, it won’t have to pass under the switches.




But this is the part where it gets difficult for me.
Three main questions

Which MCU do I use?

I wanted to do a cheapo handwired build (already have most things, only need costar stabilizers and a MCU) but it is my first TKL build, I’m afraid I won’t have enough pins for all the colums/rows.
Will the Teensy 2++ work with QMK? Will it be enough?

How do I fixate the MCU to the plate without it being permament?

In case of maintenance I would love to move it around, I need a solution that shall be non conductive and kinda sturdy enough. I don’t plan to use the keyboard as a weapon of mass destruction, but some wiggle and some vibrations are to be expected.
I was thinking about using “UHU Patafix” which are glue pads, but if anyone has anything better suited or doubts about this product hey, that’s what I am here for!

How do I attach daughterboard to the MCU?




I have these 4 cables, a friend of mine suggested to desolder the white connector and solder there a male MINIUSB (that’s the connector’s pinout) to attach directly to the MCU. So it will be like pc-cable-daugherboard-weird solder work-MCU.
It sounds like it should work, but if there’s any doubt again, please teach me!

Picture that follows is the connector before being removed from the PCB. It has VDD, D+, D- and Ground traces.






That's  the situation, really hope someone with more experience than me helps me out!

EDIT

Quick update, closing up the keyboard has given me another idea. The piece of PCB which I don't need sticks out of the plate and i have give or take 0.5 cm in height to use. Could be an option to place the MCU there and pass the row/columns wires through the lower brackets, on the sides of the "UP" arrow key?

[Maledicted]

If all that daughterboard is is literally just straight traces from the wires to the usb connector, wiring that to a another internal usb jack should work. I have a Quickfire Rapid at home. I wonder if I should rip it apart and take a look at that daughterboard.

The Teensy 2++ apparently does work with QMK, and apparently has enough pins to use up to an astonishing 529 individual switches. This is based on quick Google searches though.

This extra pcb sticking through the plate that you speak of is the keyboard's controller. What is it that's wrong with the original guts? If it is just the controller, there are actually custom controllers available that make these keyboards programmable. You may just be able to buy one of those and plop it into the original board, then solder in your switches of choice.

[nevin]

- teensy ++2.0 -perfect controller, fully QMK compatible (just note when building firmware teensy ++ 2.0 is AT90USB1286, not ATMEGA32U4 like promicro, teensy 2.0, and others)
- usb breakout/daughter board, doesn't look like there are any components on the board. use the notation on the PCB by the connector to identify what color is what when wiring a different connector
- fixing controller - since the USB that gets plugged into the computer is on a separate breakout board. the controller can even be double sided foam taped to the inside of the case or underside of the plate. (because you won't be using the controller's onboard usb connector directly it doesn't need to be fixed super securely to stay put when you plug in the keyboard to the computer)

if the original PCB is still in decent shape, just swap controllers (the u shaped daughterboard) if you have some pulled pads you can run jumpers to get those switches working again. (do some digging on repairing pulled pads on a keyboard pcb) i know mr keebs had done a bunch on stream one time. replacement controller - fully programmable https://www.1upkeyboards.com/shop/controllers/qfr-frosty-flake-controller/

another thought is see if the phantom tkl pcb will fit. (search for combinations of phantom pcb and qfr case)
https://mechanicalkeyboards.com/shop/index.php?l=product_detail&p=536

here are some good hand wiring guides
https://geekhack.org/index.php?topic=87689.0
https://geekhack.org/index.php?topic=103108.0

some good tools
keyboard layout editor     http://www.keyboard-layout-editor.com/
- here's a start of a layout that you can then dump into kbfirmware     http://www.keyboard-layout-editor.com/#/gists/1e69ace068b33554b82a9917fc7aace2
kbfirmware     https://kbfirmware.com/

[umberts]

If all that daughterboard is is literally just straight traces from the wires to the usb connector, wiring that to a another internal usb jack should work. I have a Quickfire Rapid at home. I wonder if I should rip it apart and take a look at that daughterboard.

The Teensy 2++ apparently does work with QMK, and apparently has enough pins to use up to an astonishing 529 individual switches. This is based on quick Google searches though.

This extra pcb sticking through the plate that you speak of is the keyboard's controller. What is it that's wrong with the original guts? If it is just the controller, there are actually custom controllers available that make these keyboards programmable. You may just be able to buy one of those and plop it into the original board, then solder in your switches of choice.

So, I don't think the PCB is to be trusted. First Esc started to stop working, then 1, and then \ (in the ISO italian layout they are all close to each other) and besides, it was my first basic solder desolder project and I removed everything from it, whilst I think not treating the PCB right. Switches, diodes, connector. It's not feasible to use it, it's not gonna go in because I don't trust it! That's the whole reason of the project, i just placed it back in the case just.. in case! That's why I was asking about how to place the MCU into the U cotout, it's gonna be free space.

- teensy ++2.0 -perfect controller, fully QMK compatible (just note when building firmware teensy ++ 2.0 is AT90USB1286, not ATMEGA32U4 like promicro, teensy 2.0, and others)
- usb breakout/daughter board, doesn't look like there are any components on the board. use the notation on the PCB by the connector to identify what color is what when wiring a different connector
- fixing controller - since the USB that gets plugged into the computer is on a separate breakout board. the controller can even be double sided foam taped to the inside of the case or underside of the plate. (because you won't be using the controller's onboard usb connector directly it doesn't need to be fixed super securely to stay put when you plug in the keyboard to the computer)

if the original PCB is still in decent shape, just swap controllers (the u shaped daughterboard) if you have some pulled pads you can run jumpers to get those switches working again. (do some digging on repairing pulled pads on a keyboard pcb) i know mr keebs had done a bunch on stream one time. replacement controller - fully programmable https://www.1upkeyboards.com/shop/controllers/qfr-frosty-flake-controller/

another thought is see if the phantom tkl pcb will fit. (search for combinations of phantom pcb and qfr case)
https://mechanicalkeyboards.com/shop/index.php?l=product_detail&p=536

here are some good hand wiring guides
https://geekhack.org/index.php?topic=87689.0
https://geekhack.org/index.php?topic=103108.0

some good tools
keyboard layout editor     http://www.keyboard-layout-editor.com/
- here's a start of a layout that you can then dump into kbfirmware     http://www.keyboard-layout-editor.com/#/gists/1e69ace068b33554b82a9917fc7aace2
kbfirmware     https://kbfirmware.com/

Thank you for all the links! I already did my first handwire project, the actual board I'm typing on is a 3D printed Whitefox powered by handwiring and a teensy 3.2! I'm not saying I'm an expert but I have a basic understanding on what's going on.

As for the same reasons that I explained just now I won't be fixing the PCB (faulty, not treated right by me afterwards) nor am I buying a new one it's  because I don't want to spend "high" amounts of money on this build. It's gonna be a secondary one and if it doesn't work I'll just use the MCU on some other project. Besides, all the pcbs that I looked at do not fit in this particular case, unfortunately. I could saw off some standoffs but the main one is where the screw that holds together the parts of the kb, and I can't  move it.


So the question is:

what should I use to secure the MCU to the plate? Are glue pads enough? is there something I should be aware of?

[nevin]

you can hold the teensy in place with whatever you like. (foam tape, electrical tape, hot glue, etc... anything non-conductive) like i said, you're going to have a couple wires running to the usb port that's screwed into the case, so the teensy ++ doesn't have to be bolted down to wherever you place it. it just needs to stay put with normal knocks & bumps, which all of the above should be fine.

also, here are the measurements of a teensy ++2 if you want to see if it will fit around where the previous controller was. 52mm x 18mm (i had one on hand to measure)

[umberts]

you can hold the teensy in place with whatever you like. (foam tape, electrical tape, hot glue, etc... anything non-conductive) like i said, you're going to have a couple wires running to the usb port that's screwed into the case, so the teensy ++ doesn't have to be bolted down to wherever you place it. it just needs to stay put with normal knocks & bumps, which all of the above should be fine.

also, here are the measurements of a teensy ++2 if you want to see if it will fit around where the previous controller was. 52mm x 18mm (i had one on hand to measure)

Thank you! I don't have a hot glue gun but I'll try to find one, yeah the teensy just fits! I hope there will be enough margin to glue it in place and not obstruct the pins, but i'm hopeful. The dimentions are in the first post! I measure usable 57mm x 20mm, so I'll squeeze it in one place and hope it stays there!

Thank you once again for the feedback!

[Maledicted]

you can hold the teensy in place with whatever you like. (foam tape, electrical tape, hot glue, etc... anything non-conductive) like i said, you're going to have a couple wires running to the usb port that's screwed into the case, so the teensy ++ doesn't have to be bolted down to wherever you place it. it just needs to stay put with normal knocks & bumps, which all of the above should be fine.

also, here are the measurements of a teensy ++2 if you want to see if it will fit around where the previous controller was. 52mm x 18mm (i had one on hand to measure)

Thank you! I don't have a hot glue gun but I'll try to find one, yeah the teensy just fits! I hope there will be enough margin to glue it in place and not obstruct the pins, but i'm hopeful. The dimentions are in the first post! I measure usable 57mm x 20mm, so I'll squeeze it in one place and hope it stays there!

Thank you once again for the feedback!

Personally, I find hot glue guns to be the best option of those that have been posed. That foam tape degrades over time and the adhesive practically becomes one with whatever you stick it to without some solvents. Electrical tape just starts falling off of whatever it is stuck to, and gumming up, within months. High temperature hot glue, if not directly stressed (unless you use a lot of it) will stay where it is indefinitely until you feel the need to try to pry it off, and you can usually get it all of pretty cleanly with a little patience.

[umberts]

Personally, I find hot glue guns to be the best option of those that have been posed. That foam tape degrades over time and the adhesive practically becomes one with whatever you stick it to without some solvents. Electrical tape just starts falling off of whatever it is stuck to, and gumming up, within months. High temperature hot glue, if not directly stressed (unless you use a lot of it) will stay where it is indefinitely until you feel the need to try to pry it off, and you can usually get it all of pretty cleanly with a little patience.

Yes, just found a friend that has a hot glue gun. I'll buy the teensy right away, wait for it to arrive, start with the switches when they arrive and update this post!

Thank you once again!

[Pentotark]

Hello,

I own a quick fire rapid but i broke the little rectangular mini usb b daughter board. Do you know where I can find a replacement for it?

[nevin]

i doubt the the usb daughterboard is generic, you could try to fix it/re-solder it.

but if it's beyond repair, you could replace it with another one (may not be exactly the same size/shape). just do a search for "mini usb b daughter board" and try to find one that's as close to the same size, shape & mounting pattern as the one that's broken. just pay attention to which of those 5 wires goes to which pad on the new daughter card.

[umberts]

Little update!

Found a teensy2++, wrote a firmware for it and testfitted. Then arose the problem for the connection. It's ghetto, but it works







Now to connect all the rows to all the columns!