Definitely not a personal computer for the masses, but maybe some national office gem from East Germany.
Resources
Wiki
xepb.org
robotrontechnik.de
retrobrewcomputers.org
Zander (schematics, display adapter)
oldcomputer.info (connectors, pinouts)
Documentation and service manual
Internals
Motherboard
Keyboard
Floppy Disk Controller
Floppy Disk Drives
TEAC FD-55FV-13-U drives – see spec.
Power Supply
That’s really the most impressive part of 1715, solid, heavy, massive and what an attention to details.
Power Supply Fan
Absolutely amazing, aluminium base and super quiet almost zero-friction bearings.