I've had an A-760x and an A-500x serviced and they are totally different again from previous models and are easier to work on. Rita told me that there's factory updates for the "A" series which will help prolong the life of the units, I think some resistor changes. She also told me that she doesn't see too many of them but when they do come in due to failure, it's usually pretty bad, like whole boards are burnt out.
Klipsch RB 75's
Sunfire 12" TrueSub Signature