Not only is the resistor surface mount, but the board appears to be multi-layered as well. Difficult soldering job, especially in the field. Without a schematic of the board it would be hard to tell the function of the resistor. looking at the picture the resistor in question is in the power circuit..(proximity to the fuses), which could mean a high current undervalue for the resistor. But if it's somehow included in the current/voltage feedback changing the value could change operating charteristics. If I was going to do the repair, with the little I've seen, I'd keep the same ohmage value, and try to step up the wattage.

If you had the board in hand, given time, you could come up with a workable schematic to go by....