Riddle me this you Link Belt/Sumioma experts.

[Coaldust]

160 LX serial number K2J6 0872
Man# 16003-1608

Why does the service manual not provide the specs for the proportional valve pressure/amperage test? The boxes are blank. Triad couldn’t tell me either. What am I missing? My 130 LX book has the specs.

 

[Coaldust]

Back history. The customer complaint is low power in all functions. Bogs down. Local dealer has worked on it. Customer in-house Tech has worked on it. I’m involved to see if I can help. I don’t think it’s an engine issue. The customer just installed a reman engine and sundry parts. The main wiring harness was replaced at the same time. No increase in performance after the new engine was installed. I don’t think there was much wrong with the original engine.

Hydraulic filters are clean. No visible Hyd oil contamination. About 13,000 hrs on machine. Just a brief overview. Owner operator. Looks like the machine has been cared for and not abused.

 

[Coaldust]

Update: She has an active 0080 code pilot travel function switch. It appears the power-up feature is not working. The pilot travel switch looks like it’s part of the power-up valve electrical circuit. Hmmmm.

Where is the pilot travel switch located?

 

[Coaldust]

Found that pesky switch on the bottom of the main control valve on the Rh travel spool. Now reaching it,.....

 

[John C.]

I'd like to help you on that but can only give some information from older models. On the old C2 machines those solenoids were checked just to see if they changed voltage when the mode switch in the cab was changed. A multimeter was put in series with the wiring and the measurement was in milliamps. Most of the time it you could just watch the pressure gauge plumbed into the pump control circuits. It would change each time the mode switch was changed.

It kind of sounds like a hose was plumbed into the wrong place or that the wiring harness might have something different. Maybe you can put the multimeter in and see if you get any reading at all.

 

[Coaldust]

Thanks for the reply, John.

Ah. OK. That makes sense. I should primarily be looking for a change in Amps/pressure as I move through S/L/H mode. I do have that. I’ll double check my notes.

Just discovered the power-up circuit for the two stage main relief is inop. Solenoid isn’t receiving any power.

Once the standard main relief pressure is reached for two seconds, the power-up circuit is supposed to send pilot pressure to the main relief and raise the pressure to 5500psi for 8 seconds. That matches up with the customer complaint. Plus, the standard main relief pressure is a little low. That’s my project for this morning.

 

[Coaldust]

I’ve got an active M0080 pilot travel switch code. Which I discovered, prevents the power up feature from working. It’s a simple circuit. Controller sends a 4.75 volt signal to a normally open switch. Which closes whenever the travel motor main stem is used and the signal gets grounded.

Tested this simple circuit six ways from Sunday. Unable to find anything wrong with the travel pilot switch circuit.

What am I missing?

I even swapped a known good controller from a similar machine and the M0080 fault reappeared. Hmmmm. Head scratcher.

 

[John C.]

As I recall power up is supposed to work anytime a travel function is used. The other way to activate power up was a button on the joystick. Keep in mind that the circuit is grounded through the computer. Maybe you can put your amp gauge in line with the ground side of that switch to see if current is flowing which might indicate that the computer is getting the signal.

 

[Coaldust]

New info comes to light. There is an additional pilot pressure (normally open) switch for the implement functions. This switch circuit can also create a M0080 fault code, which disables the power-up feature, when active.

OK, then. I need to locate the other switch and test.

The inductive ammeter is a good idea, John. I’ll try that.

 

[Coaldust]

M0080 Diag5, you are a bitter mistress. Lesson learned : there are two pilot switches. Either one can cause that fault.

Three Link Belt hoes on this job and every unit has at least one bad pilot switch.

 

[Coaldust]

Parts are ordered, everyone is happy and I’m headed to my next adventure. Packing up my game and headed out west. Cowboy style. Just like Kid Rock. To the black sand and gold covered beaches of Norton Sound. There’s no place like Nome where broken dreams and broken machinery await me.