| JA3 Pin: | Function |
| -------- | ----------------------------------------- |
| A | Horizontal Scan In |
| B | Vertical Scan In |
| C | Feeds into scan gen earlier than A |
| D | Feeds into scan gen earlier than B |
| E | Pull down to enable A B inputs |
| F | Pull down to enable C D inputs |
| H | Horizontal Blank (Scan sweep for display) |
| J | Vertical Blank (Scan sweep for display) |
| K | Gnd |