Ni-Wumpf board coil buffer chips
On a Ni-Wumpf replacement CPU, coil faults can come from the 7406 or 7416 inverters at U12 and U13. Each output should be the opposite of its input.
Systems
Related tips
- Bench test of coil buffers Z6 and Z7
- Spare chips for System 1 boards
- Which spider chips fail and why
- Socketing a replacement spider chip
- The six Rockwell "spider" chips on the CPU board
- Testing CPU input buffers Z29 and Z27
- Swapped U4 or U5 spider still does not work
- Check the TC3 jumper plug on the CPU board
Source: Gottlieb System 1 Pinball Repair from 1977 to 1980, Clay Harrell (pinrepair.com)