Ensoniq DP4+ Repair

I have an Ensoniq DP4+ Digital FX unit that is in need of repair. It has been through one attempt to restore it to working order, but the previous technician was not able to complete the repair. The technician was able to replace all the leaking capacitors, restore the power supply, and replace the OS/ROM chips to the latest version. Basically, a full refurbishment job. However, there is some issue with the components that gives the error “Unexpected Event Type” and the values 50, 51, and 75 (it will produce various values when you boot it up). I have read that these error codes may have to do with the general process register on one of the chips, but I really don’t know anything about it… Does anyone know about these error codes? Are there any repair shops or technicians out there who work on old Ensoniq gear?