Could be the device also may bear inspection and testing, in case
that may need replacement; there is a chance it may contribute to
the failure rate you have experienced among power supplies.
If the electrical mains and plugs in the location the device is used
are tested OK, and if you've tried using an automatic self-regulating
uninterruptible power supply (with its own backup battery) to stop
any effects of spike, surge, or quick fluctuation of voltage, the next
item to look into may be to see if the device itself places undue load
on the power supplies.
Maybe you should ask about this aspect of your experience.
Good luck & happy computing! 🙂