I still repair electronic equipment down to component level, it's a dying trade in this throw away society of today.
Manufacturers don't help, I had a PCB (Printed Circuit Board) the other day where both the component and print side had been encased in epoxy resin just to prevent it from being repaired.
For sure Lexus would have replaced the complete alternator, probably not a brand new unit but a reconditioned item, your old one in turn would have ended up on someone elses car after going through the same process.