Page 3 - A Closer Look - Disassembly and Internals
As part of our disassembly, we can start by first inspecting the keycaps. These are PBT or polybutylene terephthalate plastic with a double-shot injection. I like PBT as a material choice, as it is more durable and do not shine or fade over time compared to other commonly used plastics like ABS. The thicker wall also adds to a deeper sound when used. The legends are inserted with a second layer of plastic, which is why it is called double shot. This is why you see a gray outer shell and black inner plastic. As such, the legends will not fade or wear over time, but it is a costly option for making keycaps. The choice of font is clear and legible with OEM-like writing. The keycaps use standard MX stems with a Cherry profile. The Epomaker TH108 Pro offers full NKRO over USB. NKRO stands for N-key rollover, which refers to the number of keys scanned independently by the hardware. The keycaps have an OEM profile as well with the keys slightly concave, so users know where to rest their fingers.
The longer keys of the Epomaker TH108 Pro, like the space bar and Enter, have Cherry stabilizers on each side to ensure an even actuation and to prevent wobbling. These are factory lubricated as it has a smooth travel and do not rattle or squeak when the longer keys are pressed. The stabilizers are plate-mounted rather than screwed into the PCB. This is usually a cheaper alternative, as plate-mounted stabilizers can cause a bit more rattling. Thankfully, the stabilizers do not make much noise. The plate is polycarbonate and flexes easily under pressure. There are flex cuts in both the plate and the PCB board underneath. This affects how each keystroke sounds and feels.
One of the key selling points of the Epomaker TH108 Pro is its switch technology. Mechanical switches consist of a housing base, stem, and spring, offering varying levels of tactile and audible feedback. More specifically, these are Epomaker Creamy Jade mechanical switches. They are linear in travel and require a bottoming out force of 50g, actuation point of 2.0mm, and total travel of 3.6mm. They have an expected lifespan of fifty million keystrokes. These connect to the PCB with hot swap sockets, and the sockets support both three-pin and five-pin mechanical switches. As such, if you do not like these or an individual one fails, you can swap it out without replacing the entire keyboard.
Taking a closer look at the Epomaker Creamy Jade switch, it has a blue top and light green and blue bottom. A stem is in the middle with a 20mm spring that keeps the switch elevated. The switch stem has minimal lateral movement inside the housing, which ensures actuation is stable and the keys do not wobble about. The switches are factory lubricated for a smoother typing feel and sound. The stem is made of polyketone, or POK plastic, which is said to offer better wear resistance to traditional POM stems. The upper case is polycarbonate, while the bottom one is PA66, which refers to polyamide or nylon 66. The contact pins are a combination copper and palladium alloy.
Taking apart the Epomaker TH108 Pro is a bit more of a chore due to the use of plastic clips holding everything together. With some pry tools, I was able to expand a small gap at the back corner of the keyboard and work my way around. Unfortunately, one of the plastic clips did break in the process of opening the keyboard, so I would not recommend doing so unless you know what you are doing. Once the clips are released, the top and bottom separate from each other, but you will need to detach two ribbon cables to separate each from the keyboard deck. One leads to the screen on the top, while the other leads to the daughterboard for the battery and back I/O. It is nice to see ribbon cables here, as they prevent a moving keyboard deck from affecting more stable portions of the keyboard, such as the USB port and its back switches.
The keyboard deck sits in here with gasket mounts in between the top and bottom shell. There are eight protrusions around the deck with rubber mounts to hold in place. These gaskets should also reduce vibration or unwanted movement transferring from the deck to the rest of the enclosure. Underneath the deck, there is a thick layer of silicone to fill in the gaps of the bottom shell. It also works as an insulator for the two large batteries underneath and the daughterboard. The two batteries add up to 10000mAh, which ensures a long battery life.
In between the plate and the PCB, there are several layers of sound damping material, including a Poron sandwich foam, IPXE switch pad, and a sound-enhancing PET layer. Under the printed circuit board, there is another layer of EPDM switch socket foam and the aforementioned silicone padding. All these layers contribute to the overall typing sound and feel. Underneath the sides of the PCB, there is a column of LED lights, which produce a nice side glow on the Epomaker TH108 Pro.
Page Index
1. Introduction, Packaging, Specifications
2. A Closer Look - Hardware and Software
3. A Closer Look - Disassembly and Internals
4. Conclusion
