Rare Vintage (1980) Zenith Data Systems Z90-80 computer, with 5.25" floppy drive

“Clean condition. It was retired years ago and kept in a cool indoor environment. Computer powers on and boots to the H: prompt. DISK DRIVE: The disk drive spins and the head engages. But it does not read data. We tested the drive on another Z80 CP/M computer and got the same result from this drive. Other drives were able to read data on the second computer. We did not have the time for further troubleshooting on the disk controller card or the main board. So we lowered the price and relisted it. All the schematics and guides are included for you to repair and keep the whole thing original. MEMORY BOARD: We checked out other internal electronics and replaced components as needed: on memory expansion board, we replaced 4 memory ICs. It PASSED memory test afterward. VIDEO BOARD: We replaced 3 transistors, 2 capacitors, and 2 resistors. Monitor screen lit up afterward and displayed the H prompt.”