excavator boom not moving

[elmartinfarm]

We have a kumatsu pc75 uu-2, was running fine. Now we went to use it and have no stick function at all. The saftey switch seems to work, energized when lever is up and not energized when down. Blade moves up and down and tracks turn. Any ideas?

 

[Dr.Dc]

If all the other controls work then it just in the circuit for the stick. This will also tell you if you have a pilot problem or a delivery problem. If none of them work then look at all you filters first(pilot and main hydraulic filter). Its cheap easy and you will know if there was a failure(depending on type of material in filter will be type of failure). At that point then you have narrowed down to what side of the hydraulic it is. Hopefully this gets you started and I hope to read the result when you find something.

 

[caterpillarmech]

Do you have a pattern selector? I have seen them get out of position and make a machine function funky. Is it just the boom or all of the boom functions?

 

[Dr.Dc]

good call caterpillarmech, very good possibility, that gives me an idea on another problem I'm working on.

 

[elmartinfarm]

Have no boom function at all, have continuity on both wires to solinoid for safty switch which makes me think electrical problem. No pattern select, and is a grey market machine.

 

[89.ho.ss]

I am having the same issue. I know it's an old thread but I am wondering how you made out?

 

[elmartinfarm]

No answers, am checking pilot pump this weekend. It seems electrical to me. I have power on both sides of the lock out solinoid, which seems odd. Let me know if you get anywhere.
Good luck

 

[89.ho.ss]

Had komatsu send over all wiring for cab and controls. Looking at it now. Their diagrams are not what I'm used to

 

[normman]

I'm having a similar problem, blade move and tracks move but no control lever function. If you use the safety by-pass switch all functions work. All hydraulics work, good pressure at test ports. Code on console is "EE" and code on the controller is blank. Its a PC75UU-2.

 

[elmartinfarm]

Where is the safety bypass located?

 

[normman]

Below your right knee when in the seat on the side of the seat mount.

 

[normman]

Does your machine have any codes on the console or the controller?

 

[elmartinfarm]

Safry bypass switch did not work, controller Shows 3.6.

 

[normman]

Looks like you may have a bad offset potentiometer. We have had those go bad, over the years. We have not had a 'EE' code, it says that the controller is bad, but on a 1995 machine the price of the controller is $6,900.00 it is not worth buying. I'm hoping
somebody may have something I missed?

 

[89.ho.ss]

What does the EE code mean? I have one and I don't have power to my sticks. But I have had the EE code since I owned it (10 years)

 

[89.ho.ss]

I have power to the one side of the lockout solenoid but no power to the other one. I do get the ground to activate when I put the safety lever down. Do you get the ground to activate on yours?

 

[normman]

I found that power is going in but not coming out. But the test for 'EE' is "is there power at K1, #8, #17, #18, if so the controller is bad." That a very basic test to replace a $6,900.00 controller. How have you been using the machine? Did you bypass something like the safety switch?

 

[89.ho.ss]

I didn't bypass anything it always worked. Always had the EE on

 

[normman]

Do you have a safety bypass switch? If so has it been bypassed, electrically or may be hydraulically? Ours won't work unless you hold the switch up. It is not labeled in english, the operators did not know what it was for YEARS. Lol. According to our book "EE" code means "Abnormality in controller power source system or communication system". Basically the controller maybe bad. I have trouble condemning the controller on one test!

 

[89.ho.ss]

Mine is just really weird because it was working perfectly fine I got out of the machine got back in and then it would not work