Disassembly

Disassembly of the HV-KB390L is very simple due to the use of ten Phillips head screws that attach the metal plate to the plastic case. In order to access these, you need to remove some keycaps as seen above; be careful when doing so as the keycaps clip into place here instead of having two mating pieces as with the Cherry MX keys. A precision driver helps a lot here, and once all the screws are removed, the two pieces separate easily. With no cable to worry about, we can get a look at the bottom case panel right away, which confirms the ABS plastic composition as there is a label that states as much. This also helps confirm that the case is unnecessarily angled at the top, with a lot of empty space here, and HAVIT could have had an even lower-profile design had they chosen to (or had the OEM chosen to, depending on the source of the original design).


The PCB is blue in color and was finalized on July 7, 2017, as seen by the print on the bottom - very recently indeed. We also see that the switches themselves are soldered through the plate and into the PCB, and they have connectors similar to those on Cherry MX switches, albeit with a different spacing, so you will not be able to use these switches on a PCB designed for Cherry MX-style switches or vice versa. Solder quality was generally very good aside from two locations where excess solder or flux was applied, though not nearly by enough to affected functionality. SMD LEDs with resistors are also associated with each switch here, which goes well with the transparent housing chosen for these switches. Backlighting should be fairly good here, and the light itself is diffused through the housing on each switch.


There are a few tantalum capacitors on the PCB, including a couple by the female micro-USB port. The HV-KB390L is powered by a Holtek HT32F52314 32-bit ARM Cortex-M0+ USB microcontroller with up to 64 KB of onboard flash memory and 8 KB of SRAM. The lighting effects and onboard controls that are pre-programmed out of the box are thus stored on the MCU itself. There are also two separate Macroblock MBI5020GP 16-channel PWM LED drivers to drive the 87 LEDs here, and all the components are on a multi-layered PCB.

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