Hi Bought this from a salvage guy a couple of years back. Got it running and most hydraulic functions working correctly. It has a pattern changer, but we think this is in order. Go all functions properly, apart from bucket arm/dipper and the off set/knuckle boom. The dipper does tend to lift a bit, when you lift the main boom, it basically comes in until the ram is fully extended on the dipper, then the boom lifts, other than that it won't move. The offset won't move at all with the pedal, unless I unplug one of the three solenoids below the cab, then it just goes all the way to the end of its travel, to move it back have to switch the pipes. Looking at the spool block below the cab, starting from the left, first slice front blade, works normal, next the offset. Then the dipper spool, this is in a block with the slew, which works fine. Next block has the two track motor slices in, last block bucket and boom. I'm confused by the amount of pipes I think are for the pilot circuit that go between slices on the spool block, would have expected one pilot pipe to each service? But we have say the boom pilot pipe to a T joint on the slice, and the T off go's to a track motor block? Dipper similar. The fault is mainly connected to two adjacent spool slices, which both basically do nothing, not even change engine note or hiss of hydraulics. We think the pilot service works, as do the joysticks as if you swap things around things happen. I suspect (hope) some of the pipework between the spool slices is wrong, I have attached a picture, sorry poor quality but can upload more. Also unsure what the bank of three solenoids adjacent to the spool block do, maybe connected to the depth monitor?
Did you check the potentiometers on the offset boom? They will cause the boom and stick to lock out if they lose track of where it is. I bypassed mine in a pc50uu I had a while back.
The rod for the potentiometer on the dipper was broke, if you moved it slowly the dipper would respond, if to far everything would stop unless you switched the release switch under the seat. Mended the rod today, also spotted the other day the offset one was un plugged, plugged it back together. Do the potentiometers link up with those three solenoids? How did you bypass? Cheers
Ya somehow they do, I think it's basically to make sure you don't hit the cab with the bucket. I just figured out what wires needed to be stuck together to trick the system into thinking they were always in the right spot.
Ok cheers will have a look
Put a flow gauge in the pilot circuit on the slightly odd looking pipe on the extreme right in the picture, it seemed odd that this pipe went from the boom slice to one of the track motor slices. With the pipe fully throttled the boom worked as normal, I'm guessing this cross feed pipe is incorrect?