In replacing the USB cable on a Realforce 104UB-DK45S with an aftermarket cable I noticed that the replacement cable did not work. Windows gave a “malfunctioning USB device” error upon plugging in the board. Looking into it, I found a curious thing: the replacement cable was wired correctly, but the pinouts on the Realforce PCB were different than expected! They were not the same as the wiring on the models that are more popular with keyboard customizers, such as the 87UB TKL model: they have the DATA- and DATA+ lines reversed.
I've made a PDF with more details and pictures here:
https://www.dropbox.com/sh/5pbp4x114qe4wje/AACHDXUY1yUbc405tavXwNyRa?dl=0
Known Affected Models• Realforce/Ducky 104UB-DK45S “Ducky 2016” (model XF01RS) 45g
• Realforce 104UB-S (model XF11TS) variable-weight
• All 104s???
Known Unaffected Models• Presumably the 87UB TKL models
Correcting Existing “Normal” CablesUse these instructions at your own risk!
To make a “normal” RF cable work with a “reversed” board, you can remove the “contacts” (the crimped-on metal tubes) + wires from the D+ and D- lines are reversing them.
You can remove the contacts+wires from a Molex/JST-type connector by pressing down on the metal visible through the little opening for each wire, and also lightly prying up the plastic tongue right behind the opening. Then the contact+wire pulls right out.
Do this for the two centermost wires (green and white usually) and reverse their positions. Push the contact into the connector until you hear a click. Done! The cable will now work with a “reversed” Realforce board.
There are some good YouTube videos illustrating this process.
Some USB Cable Background| “Standard” | Pexon | USB | USB |
| USB Color | Cable Color | Name | Function |
| Red | Orange | VBUS | +5V |
| White | Yellow | D- | DATA- |
| Green | Blue | D+ | DATA+ |
| Black | Black | GND | Ground |
USB cables also have a bare, uninsulated wire which is the drain, or shield wire. In Realforce cables that wire is sleeved in black and terminates in a ring lug rather than on the Molex/JST-style connector and is connected separately to the PCB.
The JST/Molex-type connector in the Realforce is a JST EH type or equivalent, specifically the EHR-4 which has a pitch of 2.5mm.
