How to reset the TV-7216 DVR to factory settings?

Question

CCTV

Hello. There is a DVR with a forgotten login password to enter the admin panel.
On the front side it says: H.264 Network DVR
On the belly:
Embedded 16CH Digital Video Recorder
MODEL: TV-7216
POWER: DC12V 3A
SYSTEM: PAL / NTSC
S / N: 201203071 052
I found the manufacturer by googling - China, Techvision. The "manuals" section of the site is empty.
I took it apart, took out the battery, disconnected the HDD and left it in this form for a day - it did not help.
Are there any ways?

Answer 1

Programmer.