This guy added a video card because the onboard was not working proper:
https://ancientelectronics.wordpress.com/2015 … 2-model-30-286/
I suggest you do same if all else works OK and replacing the ramdac does not help.

Fantastic! I'd been told putting one in would work but this gives confirmation.

It has 3 ISA slots which is probably 1 fewer than I would want if I'm using a VGA card but I think I can get it to work.

However my top preference would be to get the onboard VGA working, if at all possible so I'm open to any suggestions anyone might have about the magenta, while hoping the RAMDAC is the answer

One time I hooked up a monitor that had a break in the VGA cable on one of the colors, and the 30-286 POST was so thorough it caught it. So if you had a connectivity problem on green then perhaps it would report it too?

PIST does report a VGA problem, yes. But at I've said I've thoroughly checked continuity right from the port to the ramdac IC and used an entirely different monitor and vga cable

I see
I wonder how the POST works in this area and how it's catching it. What if you POST with no monitor at all, then hook one up to see the results?

That's an interesting suggestion. I'll give that a try tomorrow

301,161,601,163

And 2401 are the error messages and it's the same with the VGA cable connected, or disconnected. 2401 is the one that relates to VGA.

New RAMDAC chip arrived... and I was right. Problem solved. Output is now white and the error code is gone from POST!

Congratulations on the fix 😀

I had a similar problem with a 386SX that would only run the display when the RAMDAC area was heated up. Putting a generic replacement in its place worked: Restoring VGA output on a Packard Bell 300 motherboard with built-in Oak OTI-037C video card
And now the display is fixed.

I guess some of the early RAMDAC chips are failure prone or got static shocked somehow.