UDN display driver chips
The D-8000 and seven-digit master boards have two UDN7180A chips driving segments (each handles three displays) and four UDN6118A-1/UDN6184A chips driving digits. The UDN6184A is the older part and the UDN6118A-1 replaces it; the "-1" means a higher voltage rating than a plain UDN6118A. The "A" on the 7180 means a plastic case. The UDN7180A is the hard one to find.
Systems
Related tips
- UDN display driver chips
- Characters missing from a display
- Same segment missing across one 16-digit display
- Master display board versions
- Which UDN6184 drives which display
- All score displays dead
- Using a logic probe on the display board safely
- Test MPS-A42 and MPS-A92 display transistors
Source: Repairing Williams System 3 to System 7 Pinball 1977 to 1984, Part Three, Clay Harrell (pinrepair.com)