I picked up a Tektronix XD88 on ebay a few years back. I’ve powered it on last year(2022) and it seems to have a non-functioning power supply. So, the other weekend I connected it up to an external power supply to see if it would do anything. I’m happy to report that it does show some sign of life.
I was 99% sure that if it didn’t detect a keyboard that it would fall back to serial port, but I was wrong. I don’t have a keyboard so now I’m asking around to see if anyone knows if there’s a dip switch combination that will run diagnostics through the serial port. I do have a copy of the ROM and I have been looking at that with Ghidra, but haven’t figure it out yet. If you have this info or if you have a boot disk image please let me know(michael dot kato at gmail).