IBM 7535 Manufacturing System
The IBM 7535 is a big robotic arm. I came across it by finding the remains of one at the amateur radio shack at my university. All that was left was the large metal control box and a few circuit boards. One of them with a lot of ICs caught my interest, so I looked up some of the chips on it. It turns out that it was a complete Z80 computer with serial port, Am9511 FPU, video, and tons of I/O. I was planning on reverse engineering the code and the hardware, but other things prevented that from happening.
I don't know for sure why it was included, but those non-english characters are katakana.
Fall of 2019, I tried booting up the CPU. Here are the results.
I applied the three different voltages required (+5, +12, and -12), and then realized that the lab supply could not source enough current. I looked around through some cupboards and found a desktop power supply. A quick google showed me how to use it, and the CPU board seemed to work fine. After a bit of probing (scope photos below in zip form), I found the video output. There happened to be a TV in the lab with composite video input, but a matching connector was nowhere to be found. The solution was found in those white drawers in the above photo. It seems that some soldering iron tips will fit into RCA connectors. The ground turned out to be unnecessary, so only the iron tip and alligator clips were needed.
I am not entirely sure what ARM OVER RUN means. It is in the manual below. If I remember correctly, it thinks that the arm has traveled too far in a certain direction.
Files:
Scope traces on various pins (zip)Notes on communication with the controller (txt)
IBM 7535 documentation (pdf)
Program and character ROMs (zip)