Here is a Disk II clone I found in a Apple II+ that someone is asking me to help them repair. This thing was the culprit. It is broken and I doubt if it's worth fixing unless it is the rarest Disk II clone controller on the planet.
No there is no manufacturer name on the front or back. the only thing on it is the "518400" sticker and a S/W near the "TBP28S42N" PROM chip.