Hi David,
The way to test if this is your Power supply fully is by metering out your 5v under load - Buying another Power supply could just give you the same issues due to every supply being set up a touch different for every machine dependent on reels, lamps and extras.
But only use a meter if you know what your doing as you could cause more damage if not.
Did you adjust the 12v pot or 5v pot on your psu?
Best wishes
Stu.
I believe I adjusted the 12V pot.... it worked great for a long while......