I did get the Newer Tech G3 card installed, but no video. Looks like I do need to pull the cache card as I'm having the same issue of no video from the AV card.as seen in this video featuring the same G3 accelerator card.
The 8100 is pain in the neck though. Should have probably picked up a 8600 instead, if there was any reasonably priced and good shape. I’ll figure it out on Sunday, and probably get a bottle of plastic cement if I need to glue anything back.
There is an interrupt switch I need to pull out, before I can slide and drop them other board.
