Having problems with Exact Power EP15A

Need help, having some issues with the EP15A Power conditioner whereas the voltage drops to 90 after a day on the bench under load. Does anyone out there have a schematic for this power unit or a possible cause or fix? I changed all the caps with upgrades and ran fine for a day. Help. Steve
Doger spent a lot of time and money only to find out it was the IC chip which is not available. All my caps were replaced. Let me know if you want for parts I'm selling it cheap.