I just got my first Expert in the mail a couple weeks ago and finally managed to have a closer look. The PSU was dead, so I took a ATX PSU and converted it for use on the Expert. This worked pretty good for about two days until I finally decided to put the case back together.
Now the Expert still powers on as usual but none of the two floppy drives are working. I only get orange leds lighting up permanently when the drives are connected. They do not insert disks or respond to anything.
Of course I disassembled the machine again and checked for broken connections, I even re-did the floppy power cable but the issue still remains the same. What could be the cause? Hope that nothing fried on the boards :/