u53 MC1488 is a RS-232 line driver, opposite of the the MC1489.
Problem with the drives could be a bad Floppy Controller and/or the drive buffer chips like what happened to mine...
I bought 2 810's and the 850 Communicator package at the BX on Anderson AFB Guam in 1983. 810's were $440 back then.
Antic and Analog mags were there every month...
They appear to be missing the cartridge containing the program.
If you look close at the left side, you see glue that held a cover plate over the cartridge port and joystick ports. The original ones covered up the promo-vision cartridge...