Nice snag for $300!

The resistor being bad wouldn't cause the fuse to blow. Fuses blow because of an over-current scenario. Resistors go bad by opening up and cause a no-current scenario. I checked the schematic and F3 is the supply to the +5v line on the power supply board in the back box. There are several possibilities, but I would start by checking the +5v regulator (big component on the heat sink) and see if it is shorted. A shorted electrolytic filter capacitor around the regulator can also cause F3 to blow. Check too for any wiring that could be causing a short circuit condition. These kinds of problems are generally pretty easy to find.

Good luck!

Jeff

Of course I totally forgot to mention that the bridge diodes (CR5 through CR8) could also be shorted causing the problem. Check those first

Jeff