Vintage Mac
Have a question about a CRT monitor connection
Why would these pins be missing?
The DB-15 plug on that display cable has omitted the Composite Sync signal at Pin 3, because the display doesn't support that. Instead, it uses a separate Vertical Sync signal (Pin 12) and Horizontal Sync signal (Pin 15). Pin 8 is not used, so it doesn't matter if it's present or missing from the plug.