A Look Inside

The metallic cover removes heat faster and looks nice, too. The front and rear covers are made out of plastic, though.


This is the PCB that hosts the LED indicators and power button. The connector on the PCB side was hard to remove, so I left it as is.


A look at the small mainboard.


The Thunderbolt 3 card has a heatsink to cool down the controller.


The PCIe 4x slot is occupied by the SATA expansion card shown below.


The SATA expansion card features an AP3P7R0EMT FET along with a driver IC and several SMD parts (caps, diodes, and resistors).


There are four FR9809 buck DC-DC converters on the PCB, which handle four phases. These ICs include a FET. There are three more VRMs on the right side of the converters mentioned above.


All filtering caps are polymers provided by APAQ.


There are two more VRMs on the back of the PCB.


This is the EEPROM of the DAS, an ATMEL 24C02N IC.


The SATA controller, an Asmedia ASM1352R, normally bridges a pair of SATA ports with a USB 3.1 interface, so an additional circuit must be used to bridge the SATA ports with the Thunderbolt 3 board. The ASM1352R also acts as the RAID controller, supporting RAID0, RAID1, JBOD, and SPAN. Close to the ASM1352R controller is a Macronix MXIC 25L4006E CMOS flash memory. In the same area, I also spotted a Realtek RTL8153 Gigabit Ethernet controller.


This heatsink cools down a transformer, which seems to be utilized by the VRMs that feed the Thunderbolt 3 card with power. Given you can charge other devices (e.g., laptops) through the TD3 ports, a capable power circuit is required.


Although there is room for a TVS diode for voltage surge protection on the PCB, that spot is unfortunately vacant. The AP3P7R0EMT FET at the input of the DC signal acts as a switch. Once you press the power button, it closes the circuit and you have power.


The I/O ports of the PCB.


The RAID selection rotary switch.


Yeehon provides the cooling fan, and its model number is A8025L12S. It most likely uses a sleeve bearing, which doesn't last as long as fluid dynamic and dual ball bearings.