[IC] 660C-X: A custom MX compatible PCB for your FC660C aftermarket case

Hi everyone, I wanted to start an interest check for a custom PCB/plate combo I had designed in order to get an MX style board in my Heavy-6 case. While I love my Topre board, I had 3 Heavy-6 cases and didn’t necessarily want the same board in each one. So far I have only tested this in my Heavy-6 but since the original plate and daughterboard design were copied I believe this should fit any other aftermarket case for the FC660C.

The setup I have in my first version is a POM plate which has some pretty serious flex in the middle due to the mounting points being only on the sides of the case. I personally dig the little bounce it has but some may prefer a stiffer plate. I am not entirely sure what all plate options I will be able to provide but wanted to see what people might be interested in. I also had 16 RGB LED’s designed on this board for underglow since I had it installed in my polycarbonate Heavy-6. This obviously won’t be a benefit to a lot of people as there are only a handful of these cases out there but I will probably leave them on there anyways.

If something like this interests you please take a moment to fill out the form and let me know your thoughts!

Link to IC form here.

Huge thanks to @norbauer for making such a beautiful case that I bought it multiple times, as well as sharing vital info with me in order to get this made. Another huge thanks to jtallbean, the designer of the PCB, for taking my wall of texts of ideas and turning them into a reality for me.


I’m excited to see this project IC, and follow the developments!

I think @norbauer will be terrified(/delighted?) that you just removed his primary concern with doing another round of the Heavy-6. I can imagine an appetite for PC Heavy-6s specifically, due to the LEDs, and perhaps interest in other finishes as well for those who stray from the Topre path and are compelled by the MX compatibility :smiley:

For the true Topre-devotee: did you explore ways to add similar LEDs to an actual FC660C (likely through a HASU-esque custom daughterboard)?


I’m so into this.

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I love this project. After years of reverse-engineering housings around other people’s PCBs, it’s pretty awesome to see someone actually make a keyboard to go into one of my housings. :slight_smile:


This should fit the original FC660c plastic case too, right ?

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I did not explore this as I have no idea how I would even make that work. I also think the niche (LED’s for polycarb Heavy-6) within a niche (aftermarket Topre housing) within a niche (mechanical keebs) might yield a total of 5 people interested in something like that. :rofl:

Well to be fair, you did pick a great board to create a housing for! I just needed a little more variety for all my Heavy-6 housings.

I don’t see why it wouldn’t. Do you have a super sweet modded stock case?

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I actually enjoy the stock case a lot too. It would be a nice way to create a new board : put your fc660c internals into a Heavy 6 and make a same layout mx board using the fc660c case.

Even better than the fc660m, you would have programabillity, desired switches&stabs.

I actually remembered there is a custom PCB too for the fc660m, available on taobao on Ydkb shop, same guys who made the fc660c/980c BT & programmable controllers

Going to look into this further but the PCB might actually fit the M as well, jtallbean designed an on-board USB port in addition to the daughterboard.

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@AdrianMan at the risk of sounding behind the times, have these pcbs ever been available outside of taobao? i don’t feel comfortable yet buying from proxies. am i out of luck?

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You will need a friend from China or a proxy to get stuff from taobao :frowning:

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Very cool project!

Now on to make pcbs for other @norbauer cases as well :stuck_out_tongue:

You read my mind…


Small update (10/01/20): I have ordered full and half carbon fiber plates to test further. The POM plate (and most likely any flexible plate) will not really work on this board due to the mounting points being only on the sides of the case with nothing on top and bottom for support. Over time testing the POM plate, I actually had a noticeable sag in the middle of the board. I will most likely only offer stiff plates for this PCB.

I am also in the process if acquiring a stock FC660C plastic case just to be 100% sure this will fit that as well for anyone interesting in replacing their stock boards. I am also on the hunt for a FC660M so I can do some tests with that as well to see if we can get compatibility for that board too.

So far the interest check has been promising, albeit for a pretty small run, but hopefully this can become a reality!



Would 100% be in for a Norbaforce pcb.

is this still happening? Definitely in if so!

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It is! I just hit a hiccup with the plate design and need to iron that out when I get some free time.


Update (11/06/20): I figured I’d at least post some pictures of the PCB and a few plate prototypes I am testing out, this might clear some things up for a few people. There are also a number of things I have discovered I’d like to address:

  • I have come to conclusion only stiff plate options are going to work, and I think only full plates as well. I am limited to the side mounting only option, so there isn’t any support in the middle of the board. This works fine with the FC660C because it’s extremely stiff all the way through.
  • To that end, I will be ordering a another round of plates, probably in brass and steel next.
  • I have not tested the half plate yet but I do not think it will work, it might be too flexy. The flex might not be too bad, as long as it snaps back into place. On the POM version I had there was a noticeable sag in the middle of the plate and the keys all sloped in. I have dubbed this the “hammock mount”. It looks like the board is broken but I will admit it was fun to type on, it had a nice bounce.
  • I can confirm this PCB will not work in the stock FC660C case, nor will it work in the 660M case or as a PCB replacement for the 660M. Both the C and the M have a big hole in the the PCB to allow a post to pass through for the stock case to come together. I do not plan to adjust this PCB/plate to accommodate that.
  • I am pretty close to being ready to open this up for sale, I just need to address one issue I am having with the plates. The aluminum plate is the first version of the design and it works fine. The carbon fiber plate is a revision to slim down the edges and have a better universal layout for split backspace as well as stepped caps lock. For some reason, the carbon fiber plate is exhibiting a slight bowing when I install switches into the plate and PCB. This does not seem to happen on the aluminum plate. This could be a slight manufacturing defect or it could be something weird that happened in the file when the changes were made. I have just received a set of calipers and I will do some precise measuring to see where the difference is between the two plates.

I have not decided on a final color for the PCB but I am leaning toward just a black with gold tracing. The white doesn’t look so great after you solder. Any feedback is more than welcome, maybe there is something I am missing that someone out there can point out to me to make this thing better, let me know!

Here are some pictures of the current plates and PCB prototypes.


probably in for 2 pairs for this!