Possible procedure for another model.

https://www.manualslib.com/manual/757069/Signet-Qv-3020.html?page=15#manual

Quoting: "Chapter 5: DVR Setup -
5.15 Video Mode
This option enables you to select between PAL and NTSC video formats.
This unit comes packaged with PAL format cameras for use in your region; as such
you should not change this setting.
Chapter 5: DVR Setup -
5.16 Factory Reset
Press the [ SEL] button to restore the unit to default, the DVR will reboot and all
settings (including the password) will be restored to the factory default settings.
Caution: There is no confirmation dialog box after pressing the [ SEL] button!
If you have forgotten your password:
And the unit is not recording; keep the system on the main screen, and then press
the [Pause] button ten (10) times in succession, the DVR will then reboot with default
settings. Note: The default password is the [CH1] button six (6) times.
If the DVR is recording, you will need to disconnect the HDD to force the machine
to stop recording prior to resetting the machine to default. "