So, I was going through some old 1050 drives that I recently picked up. One of them had a wire and 2 position switch coming out of the opening for the on/off switch.
I figured it was a write-protect switch of some sort.
Anyway, upon opening it, I found a small 14 pin chip that had the markings scraped off and "1050" marked on it. This chip was sitting on top of 74LS74A chip as shown in the picture. All of the pins from top chip were making contact with 74LS74A underneath it. Pins 11 & 12 of top chip have wires attached which go to the 2 position switch.
Switch has 3 legs and I assume that the 2 positions are either side shorted to center leg. However, unless the switch is bad, only one position shorts one side to center - and the wires are hooked to the center and the side that never shorts so if the idea was to open/close the short on pins 11 & 12, that never happens as is. They're always open.
Anyway, would love to know if one of the experts here has ever seen this or can figure out what shorting those pins would do.
Edited by cx2k, Thu Nov 8, 2018 10:14 PM.