The Topre 87U is unquestionably my favorite TKL of all time. Unfortunately with Topre, keycap options are quite limited. I am also a huge fan of high profile caps, such as SA profile caps, and luckily Topre actually makes a full size keyboard called the HiPro that features high profile dye-subbed PBT keycaps. So, if you have the money to buy both, you can simply swap out the caps, right?
Unfortunately, no. Because the HiPro only comes in a full size variant, like all full size Topre boards, the status indicator lights (Caps, Scroll, Num) are above the numpad. The 87U, due to not having room at the top of the case for these lights, uses under switch LEDs. Due to the position of these LED’s the bottom left CTRL key features a special slider, and slider housing, to accommodate for the indicator LED (on the 87U Caps and CTRL can be swapped via a DIP switch, and in that case there is a Caps LED where CTRL normally is). Because of that, only keys made for the 87U, and that left hand slot can be used in that location. Here a visual example of the difference:
As you can see, the left slider and left windowed keycap, have stems that go in the opposite direction of all the other stems on the board, which are like the other stem pictured. To further complicate matters, the housings is also different.
The left CTRL housing has a cut off corner, thus turning the housing 90 degrees, or swapping out the housing all together is not possible.
Now, there are a few solutions to this issue, with the first being to modify the keycap stem, or 3D print a new slider for that location. Cutting the keycap stem off was simply not an option for me. I feel like there is a huge possibility of making a mistake and ending up with a keycap that doesn’t sit properly, or simply doesn’t lock in place at all. I decided the best course of action was to simply modify the plate to allow the housing to be turned 90 degrees, allowing me to keep my keycaps stock and allowing me to very easily swap the entire housing back if I ever wanted to make the 87U stock again.
Do do this, I simply used the grinder on my Dremel tool. Cutting the plate was extremely easy to do and came out looking rather good. I could have sanded it down slightly more, but I wanted the housing to snap into place and not be loose either, so once the housing fit I didn’t shave any more of the plate off.
Now that my slider was in alignment with all of the others I simply needed to desolder the LED from the PCB. With the housing turned, the LED hit the bottom of the housing. This was a very easy process, and the LED came out without any issues.
After that I simply put the keyboard back together, and put on my fresh caps. In this example, I used caps from a 104US and swapped out the sliders for purple silenced sliders, as I no longer have any HiPro caps at the moment. The 104US caps would have the same compatibility issues as the HiPro caps though, and still are a good example.