What are non-repeatable faults?

Non-repeatable faults are faults that NEVER appear under standard test conditions, such as in the Liquid Audio workshop, but always appear for the owner.

These faults are separate and different from intermittent faults, which appear sporadically and unpredictably for both owners and technicians. Non-repeatable faults are exceedingly rare and are often not indicative of a real equipment fault, but some other issue with a customer’s equipment or wider system, configuration, etc.

In the few instances that I’ve dealt with non-repeatable faults, most were customer-induced: one from a bad interconnect, one from incorrect connections being used, and a few others along those same lines.

One I saw recently with a Quad 909 power amplifier has me stumped, and I don’t think it is a customer-induced issue, but there will absolutely be a reason it only appears for the customer; we just need to invest enough time and testing to determine why that is.

Very occasionally, a certain combination of environmental circumstances, connected equipment and test conditions may be needed to replicate a normally non-repeatable fault.