I have a rev 6a A500 which was working very happily with a 1st gen ACA500plus + ACA1221, with a "Matze" graphics card on a Zorro-Adaptor. I just bought an X-surf-500 to complete the setup and it's all gone wrong after installation. From what I can tell the X-surf-500 has done bad things to the ACA500plus.
1st boot with X-surf-500, amiga doesn't boot at all.
2nd boot, after wiggling all connectors, the DisMo gets to 14 and stops
Unplug everything, start again.
Repeated attempts with / without the Z2 card eventually gets to the ACA500plus's boot screen, pressing F1 to start booting the default config makes DisMo count to A3, then everything goes black. No CF activity on either card, no floppy noises.
A rather unscientific process of plugging in things at random has got it roughly back to where it was, but it's not as stable. It can take a few reboots to get started now, whereas it used to spring into action.
I've not been brave enough to try again with the X-surf-500. Is it possible that it causes a clash with the Z2 card, or is it on a different address space entirely?