NEC NEAX IVS2 PBX with NEAXMAIL AD-8 - hard drive clone issues

Hi Everyone, Not a classic computer but has a 386 embedded in it for the voice mail. I rescued it from work. We had it rung for 20 years straight. The voice mail (AD-8) is basically a 386 running MS-DOS 6.22. So my concern is the hard drive. It is the original 2.5 inch IDE IBM Travelstar 6 GB drive. It has bee running for 20 years except for a handful of extended power outages. Hence while it is working now, I don't have too much hope for the future. The PBX had its on battery backup and also was always connected to a UPS. I have tried to copy it to an industrial CF card but no luck. I have used Rufus, Active Disk Image, and Macrium Reflect. I don't have my older PCs up and running at the moment, hence I have been trying with a Window's 10 machine and USB adapters to no avail. Since the voicemail card is running headless, I can't see the error messages. There is a serial port but but I have figured out the settings yet. Any suggestions? Do I need to get a DOS machine running to do this? And yes, I really don't need the voicemail working, nor do I need a PBX in my house but why not?