Choreboy wrote:
The computer output was easier for a probe, being holes. None of the 15
holes carried any signal I saw. Two sat at 5V. The rest were at
ground. With a DMM, one of the signal holes (horizontal sync, I think)
showed zero ohms, but that could be normal.

That's not normal, there should be at least 75 ohms to ground.

---
Met vriendelijke groet,

Maarten Bakker.