Hi there!
I have a TS8OA-3520D-FLK V3.02 20131017 HCSN 14 10 DVR motherboard and I am not able to find any way to hard reset it. I could not managed to find any reset button or any reset pads on the board. There is any way to reset this board?
More images at higher resoltion here: https://drive.google.com/drive/folders/1HD8QZqcvfT_hpR03kMSyr1TnxShdloCU?usp=sharing