Disassembly

Most metal frame/case keyboards are easier to disassemble than plastic case variants, and the Cooler Master SK621 is no exception. There are 13 countersunk screws with Phillips heads underneath or between keycaps, as seen above, and a precision Phillips screwdriver comes in handy here once you have those specific keycaps removed. With these screws removed, it is as simple as lifting off the top piece to allow for enough room to move the two pieces apart, although not fully just yet. There are four small internal cables to dislodge off the respective connectors on the PCB first, including the usual USB cable for when you use the SK621 in wired mode or for charging. This cable goes from a daughter PCB on the bottom case piece to the primary PCB itself and contains the USB Type-C port we saw before. Then there are two 2-pin cables for battery connection and power, and a third 2-pin cable from the toggle switch to the PCB to turn on/off Bluetooth operation.


There is also a lot of insulation to prevent electrical shorting from metal frames touching the daughter PCB, as well as providing more room for the screws to occupy in this otherwise tiny case. The layout in the case is cleverly designed, with Cooler Master making good use of the limited space to fit in two separate 2000 mAh batteries (4000 mAh in total) to power the keyboard in Bluetooth wireless mode. There is a cutout on the side to accommodate the Bluetooth toggle switch, which is on the flimsier side compared to the build quality of the rest of the keyboard, and the insulation is frosted white to also better diffuse backlighting. The primary PCB employs a fairly unique two-tone color scheme with a cream white on the outside and black on the inside.


Solder quality is really good, as with the SK630 before, and indicative of mass production on a machine to allow for the precise soldering while maintaining the larger production volumes expected from a mainstream brand. Powering the Cooler Master SK621 keyboard is a Holtek HT50F52 USB microcontroller, which we saw put to good use in RGB-backlit mechanical keyboards from Ducky and others in the recent past. There are also two Macroblock MBIA043GP LED drivers for the RGB lighting control. Cooler Master is also using a Top Power TP4056 Li-ion battery charger module with integrated thermal management to help ensure longevity in use. The switches are soldered through the aluminium frame and on to the PCB, making them hard to take apart without a de-solder job. All the components, including the switches, LEDs, and capacitors, are soldered to a multi-layered PCB.

Before we move on, be advised that disassembly may void the warranty and that TechPowerUp is not liable for any damages incurred if you decide to go ahead and do so anyway.