So a friend of mine asked me to have a look at his brothers Rat which apparently was plugged into 18v rather than 9. I assume he took a look inside and realised the black resistor (theres a scorch mark on the PCB) was damaged and so removed it.

From the looks of things, the PCB itself is fine and there are no obvious physical flaws with any of the other components but i'm not entirely sure what would be likely to go in that type of situation.
If anyone could tell me what the value of R1 is, it'd be greatly appreciated, the schematic that's all over the web seems to have divided opinion as to wether its 100% accurate or completely useless. Any info on other components vulnerable to such an overload would be usefull too

Thanks a lot