Fellow operator was washing out our 47 meter after job today and he couldn't get it to shift back to other material cylinder when he tried. What should we be checking that would cause this problem?  Didn't get a chance to see if he was able to get it cleaned out or not hope he did.

check inside could be some blockage.

popped fuse for accumulator dump/grate switch. Probly to late now but you can push in palm valve to bypass electronics. If it still dont shift either rear busshing packed excessively with grout or cuss yourself for not changing your hyd filters and replace the little A10 hyd pump. 

Maybe the hopper grate was open. I know it sounds silly but have had people call me before saying the same thing and the grate was open. It could be a proximity switch that is bad. Try disconnecting one or use the stroke kit.

a little piece of wood and the manual control valve, as long as you have pressure

All of these are possible,what brand? We have had issues on our Putz pumps with the hopper grate switches going bad or. Wing damaged