The ProPSU (Prophet-5 Power Supply Replacement Kit) replaces the old Prophet-5 transformer and power supply board with a brand new design by Stefan Huebner, a renowned German synth tech and electrical engineer.
This new design is available both for rev 2 and rev 3.x, and resolves the three main issues with the original design:
Heat - in the old PSU the 5V supply is pulled down from a much higher voltage, resulting in a lot of excess heat. In the ProPSU the 5V supply has its own dedicated winding in the transformer.
Mechanical instability - the old power supply board is "hanging" from the voltage regulators in one end and the large filter capacitors in the other. A common point of failure is that the voltage regulator legs simply break off. This can ruin the sensitive CEM/SSM chips and other things inside. The ProPSU includes a solid aluminum heat spreader bar that is screwed onto both the new power supply board and the original heat sink. No more broken regulator legs!
Protection - The old power supply had no protection for over or reverse voltages. This can be dangerous because if one of the rails fail, the others might "swing" over to their reverse voltage for a brief time - enough to fry your CEM/SSM chips. The ProPSU has over/reverse protection on all rails.
For more tech details about the ProPSU, check Stefan's home page.
NOTE: This kit requires drilling and some soldering. Also please note that installing this kit means rewiring and soldering mains voltage cabling (110-230V). Please be careful and follow the instructions closely. If you feel insecure about this, please consult a synth tech. See the Assembly instructions page for more info.