I'm a rookie repairman. If I do something wrong, I'd expect to eat that cost. If I did what I think every other guy would do (a logical repair check list) to diagnose a machine, and then several purchased parts later, only to find that the unit is totaled, do I deserved to be paid for my time and the materials purchased?
I asked a similar question before and was left an interesting comment; someone asked whether I had quoted "replacing the parts" or "fixing the unit". Another answer was about the $25,000 Hammer Fix. Regarding that answer, if hitting it with a hammer doesn't work, who is ethically liable for the $25 hammer?