I know this is an old topic, but as I am working on my damaged MXS 5.0 and had also that resistor burnt but readable, I can say it is a 3.3 Ohm resistor. I have replaced it with a 2W one.
BTW, I need to know what the SMD TR marked component, just on the bottom part of the PCB, connected to that R26, is. I guess it should be a transient supressor, but don't know the voltage value nor if it is bidirectional. On my unit, seems shorted.
Thanks!
Jose