Access Harddisk after replacing it DS-7604NI-E1

Hi I recently replaced the 1TB hard disk in my DS-7604NI-E1 with a bigger disk, now I need to access the files that are stored on the old disk. I'm not sure what file system HikVision is using. Can I just connect the Hard disk to an external connector and read the files of it? If not, how could I do it (I know I could put it back in, but then aren't the files getting overwritten (the disks was already full).

Thanks for your help.