Hey everyone, I've been through quite the adventure getting my X68000 PRO up and running, and thought I'd share a discovery.
In my setup, I modded the PRO to provide TERM power on the C-50 port, and power the ZuluSCSI that way. I'm using a very ordinary DB-25 to C-50 SCSI cable, one I've used with classic Macs plenty in the past.
WRT the issue, I found a handful of posts here, and in other X68K forums, where people got intermittent/unstable results when using the ZuluSCSI v1.1 (STM based, not RP2040) specifically. Symptoms are that sometimes it would hang at the SxSI boot screen, sometimes it would get to the Human68K boot and hang on one of the drivers, sometimes would get all the way into LHES and hang when trying to perform some activity or launch an application.
In all instances, the thread died, or the user simply switched to another device.
Not having another device on hand, I started thinking about what could make the system marginal like that, and noticed an unpopulated footprint on the ZuluSCSI, labelled on the back side of the PCB as "Optional SCSI ACK filter cap".
Untitled.png
Untitled2.png
What's the worst that could happen?
Chucked a little 22pF ceramic capacitor in there and, bam. 100% rock solid bulletproof.
22pF was just the value I had on hand. To my reckoning, a larger value like 100pF or some nF might be 'better', but it works so I ain't touching it now! :D
I don't own a V2/RP2040 Zulu, so can't comment on those.
Hopefully this will help someone out there!!