Hi, This may seem a bit simple but I'm having trouble with a manager who is approving a retrospective validation (OQ) protocol. I have a list of alarms that I can stimulate, which is fine, and then more alarms that I cannot stimulate due to catastrophic damage/failure to the equipment. These alarms are listed and an explanation beside each stating why they cannot be tested (e.g. would need to damage the motherboard!!!), but now the approver wants to know how I know that these untested alarms work! Normally there would be some sort of manufacturers documentation to reference, but this piece of equipment is here over 20 yrs, so no paperwork!!! I have searched FDA guidelines high and low to find an actual statement stating that if catastrophic failure occurs do not need to test alarms but so far cannot come up with anything! Fact is, I don’t know if alarms work unless machine decides to pack itself in or we cut interlocksE-Stops/ etc, but this doesn't seem to cut it with him!Any ideas???