This may be obvious to everyone, (But I did not think of it right away so maybe not.)
I you have an old SCSI jazz drive or SyQuest drive around that you have no need for break it open and check out the connectors. Inside, I found normal 50 pin scsi and HS power ports (Well why not?)
Cutting...
I have a 6100, angle adapter, newertech processor upgrade and two apple av cards (not hpv), two Apple Video - VGA adapters and an old multi-scan VGA monitor (optiquest), and OS 7.6, 8.6, 9.04
No matter what combination of these items, I use I cannot get the AV card to display on the monitor...