I originally posted the initila problem in the large-format section, but since this is on-going I thought it might be more appropriate in the PhaseOne section:
Hardware & software: New PC running Windows 7 64-bit, i17 920 2.16 gHz quad-core, 6gb triple channel RAM, PhaseOne recommended SIG Firewire card, Capture One 5.1, PhaseOne 64-bit driver 188.8.131.52019, H20 on Mamiya RZ.
Problem: Despite being assured by PhaseOne that this would work before the new computer was built, it doesn't. Connecting the H20 gives the 'isochronos' (asynchronous) error. Windows Device Manager confirms the H20 is connected and working correctly. Various other Firewire cards (all Texas Instruments chip-sets) have been tested but all give same error. PhaseOne suggested a 'legacy' Windows Firewire driver. This connects the camera to C1 but firing causes immediate 'blue screen' total system crash. Nothing else so far suggested by PhaseOne has so the case continues.
The only way we can get the camera to connect to C1 is to remove 4 gb. RAM reducing total to 2gb. The issue seems to be that the PhaseOne 64-bit driver does not work with 4gb. RAM or more, despite their claims that it should, and I don't seem to be alone in experiencing this problem according to the PhaseOne user forum.
Has anyone out there successfully shot tethered with an H20 (or any other back) using Windows 7 64-bit with 4gb. RAM or more? This has been going on for three weeks now.