J2 switches the clockspeed of the 33c93/A chip between 7mhz and 14mhz
J3 enables/disables Autoconfig
J4 enables/disables Autoboot
J5-J9 Memory size/population config
J10-J12 SCSI ID of Host controller (default is all 3 jumpers closed, which is ID 7)
The HC+8 is a good card. One of the fastest ZII cards I personally remember owning/using. However, there are a few things you should know:
If it's randomly locking up with the access LED on solid, then chances are you have a bad connection at the cardslot, bad connection at a simm socket, or it just doesnt like some one of the SIMMs you have in it. (The dram conrtrol design on this card is a little temperamental. Once you find a good combination/config, its rock-stable.. Its just that some times you have to do some trial & error before you find a memory config/combination that it likes).
I also would not reccomend powering a drive off the card, unless its a low-power device like a CF card or maybe a modern notebook drive. Alwayse power internal drives directly from the PSU, not from the +5v/+12 on a zorro card.
