to diy, also have to find how whats the actual problem first..
remove the knobs and turn the pot shaft directly, test if its working.
If not,
for a start, visual check the wirings to the pots and see if all the wires are intact and whether is there any loose wire hanging.
if all wires ok, get a multi meter, connect the 2 leads from the meter to middle and left(or right) point of the pot, turn the pot shaft and see if the pot is working ok.
if everything seem to be ok but still volume and tone not working, imho, save the trouble and look for guitar tech. It will be easier and faster.
Diy to troubleshoot problems sometime will waste lotsa time and doesnt guaranty problem will be solved.