Diagnozing Sanguinololu instructions? (no replies)

Hi,

I've got a second hand Reprap with one Sanguinololu which was reported by the previous owner as having a defect and it's replacement which may be having a problem (discussed here). I'd like to repair the first one and need to check the second. So I was wondering, is there some kind of checklist you can go through to determine if a Sanguinololu board has a problem and if yes, where the problem is?

Best regards,
Ming-Hua