Hi JK, I am pretty new to this blog/thread thing, but have lots of exp. with Copco and Sandvik equip. Other than what diags are avail. on a readout of the computer (if equipped) what I would usually do is narrow the issue down to three things...Mech, Elect, and Hydraulic... once you have narrowed that down, there are three diff. approaches... Noises, heats, and movement for mech. using a meter for electrical, and then temp, pressure and flow readings with the hydraulic components... once you have narrowed those things down, it gets a little easier...hope that makes sense to you? -Doug