Altos 386/1000 boot/diags images?

Long shot, but you never know... I recently obtained an Altos 386/1000 system (80386 + 4GB RAM in a tower case with tape drive and floppy) After a quick clean and check it powered up, gave a whinge about a flat battery (which I'm told is to be expected), and then booted SysV r3 Unix OK. After an hour or so poking about, I shut it down then powered it up again a short time later... Now, it starts up, does the power on checks (including the battery whinge), loads Unix, prints some information about memory and a 16 user license then stops. No more messages, no keyboard input, nothing. So I'm a bit stuck. I've found some manuals online but they're not really helping - I'll take it to bits later and see if I can read the internal SCSI drive on another system but I'm not convinced there is an issue with the drive though. So wondering if anyone knows of any installation (or diagnostic) images for these machines? It has a SCSI tape drive and I have some tapes for it, so with some SCSI shenanigans I'm fairly sure I can write a boot tape on a Linux system, or maybe even the floppy - but I need the images... Any clues? Thanks, Gordon