I am helping my dad figure out his excavator that had sat for a couple years. It is a Kobelco Sk-200LC sn: YQ-02513 We cleared out a mouse nest in the controller area. (gross) Engine starts/runs but display screen wouldn't work. No hydraulic movement at all. No throttle adjustment. No shutdown at key. E-stop frozen. Had to shut down at engine. Checked fuses and found broken terminals in the fuse box. Repaired fuse box terminals, replaced all fuses, checked continuity. Checked all other wires. A few were missing some insulation but still intact and not touching anything. Still nothing. Well, buttons on display terminal do seem to work. Buzzer works. Win wiper works. A/c seems to work. Checked the pilot solenoids under cab. Cover was smashed. The outermost solenoid valve (I believe is pilot safety) had damaged wires. Disconnected wires to it and adjusted the valve all the way in to bypass. Still nothing. Opened Mechatronic Controller box. No obvious burns but there is some debris clustered near some of the micro controllers. Next thought was to clean the circuit board. Hoping he doesn't need a new CPU. This is a personal use machine not making money so hoping we don't need to spend $$$thousands to repair. Thoughts?
I will try to post some photos here:
last of my photos:
Can you post up some closer pictures of inside of the controller. It's hard to zoom in on my phone but it looks to me like alot of corrosion inside controller. The lcd screen on that model was a common fault. If the buttons around the screen work it just needs a new screen.
I will try to post better pics of the controller in the morning. I spent the afternoon cleaning the board. Once debris was removed, the corrosion seemed very minimal. The display worked when parked. They just go out like that? It’s not completely dead either, when I start the machine I get a partial quick flash of some Japanese symbols. Then blank. I will look for new screens tonight. Any idea how to remove the display? I already spent way too much time just removing the vent bezel.
LACHAU, the labels help tremendously! thanks. Does it matter that my Mechatronic controller p/n ends in "F2" instead of "F1" as shown in your parts list? Also, should I be looking for a new display or a new cluster controller?
LACHAU, I opened up the C-2 Cluster Controller and checked the boards. No damage or debris was present. It looks brand new. Not to say it isn't the problem but at $700 replacement I would like to be sure. Gonna keep tracing wires. Is there any way to test the Cluster Controller to confirm if it is good or bad?
Kobelco ireland, here are more pictures of the Mechatronic Controller now that I have cleaned the board. I looked for the Cluster display but cannot be sure of the part number until I get it removed. Otherwise, it appears that I would need to purchase the entire C-3 Cluster & Switch Assembly which would cost $900. I see similar looking displays going for only $100 and would certainly go that route if possible.
BTW; Is there any way to move this machine in its current state? It is kinda parked in the back property. Moving it closer to our barn to complete repairs would be very helpful.
You need to figure out why you have no hydraulics, you said you bypassed the safety solenoid by screwing in the centre of it. With that solenoid by-passed even if controllers are in trouble or even removed you should still have hydraulic movement with engine running tho it would be painfully slow. As for your c-1 controller on certain parts of the board there is corrosion across different circuits on the board which means that controller is no good but to be completely sure you would need the display working to see the faults on screen. If you fit a new controller you need the screen working to calibrate the new controller by A-adjustment. You have a expensive repair ahead of you. If it was mine I would try figure out why hydraulics are not working first, is there hydraulic oil in it, is the pump coupler OK. If you want to move it you can remove the centre shaft from the final drive and drag it close to your workshop but be careful with shafts removed the machine will roll freely and can run away on you
Kobelco ireland, I appreciate the info though sounds bleak. As you suggested I will concentrate on hydraulics for now. How would I check the pump coupling?
Sorry about the bleak info but know from experience that series of machines are hard to find parts for and very expensive when you do. Easy way to check pump coupler is connect pressure gauge to pilot pump and start engine, if pump coupler is in one piece and rotating hydraulic pump you will see pressure on the gauge. Are you sure it was definitely the dead man solenoid you screwed in. Solenoid you are looking for should have wire tag with sv-4
Kobelco ireland, Ok looked at the pump assembly and decided to pull the little gear pump off the end to see main pump shaft and it was spinning.
Kobelco Ireland, you called it. I had bypassed the wrong solenoid valve. I couldn’t read the valve number but identified the valve I bypassed as “F” on the block. When I went back and bypassed valve “K”, then the hydraulics worked. At that point, it took some time to break free the tracks (it’s below freezing here) but after awhile we got it to limp back to the shop. So, now we have hydraulic actuation. We still have no display. No throttle control (not even manual on the console) and no shut down (aside from e-stop pull). Per your recommendation my dad is willing to purchase a new mechatronic controller. Should we also purchase a Cluster Controller or might the new Mechatronic controller sort that part out too?
If your machine harness is trouble. You also can adjust the 02 PSVs located on the main pump regulators to temporarily operate.
Not sure yet if there is problem with the harness. We were able to get hydraulics working after I bypassed the correct solenoid. The next question is whether we need a new Mechatronic Controller or Cluster Controller or both. I can't find a way to diagnose the Mecha without having the cluster working. I did check everything [battery relay, fuse box, cluster control] for 24V and everything checks out. My hunch is that the Mecha is toast. Kobelco Ireland agrees.
circuled is where I can see bare wires makes me wonder what we can't see deeper in the machine. I would not be plugging a new controller in a machine with unknown history and possibly wiring faults. You had furry friends living in cab? My advise would be get the screen working first. If the buzzer works and the bottons around the screen work it's only the lcd screen is faulty. If you get screen working we can work through the faults that appear on screen to find out if there are caused by broken controller or if you have other faults in the machine as well that could break the new controller (I.e. Damaged or shorted wires). There needs to be a lot of wiring/solenoids/throttle motor etc check for continuity, resistance, and shorting. Seen a few people over the years not take time to check things over correctly and instantly fry a new controller.
Is there any risk in running the machine without the Mechatronic Controller and Cluster?
With bare wires there is always a risk but it will run it will just be very slow
Definitely had some mice living in the machine. We checked a lot of cab wiring and from what I could find the wiring at the relay you circled looked to be the worst of it. The screen is rather odd; it powers up (all pixels light) then it goes blank then comes on about 30% with pixels and the other 70% blank. Not enough to see any codes though. I took another look at the display assembly and I think I see how to remove it now. I also checked it for power and it checked out at 24v. Other wires I checked had really low voltage... CPU fault, which I believe was Pink and green (?) read like 0.3V or something. I didn't understand and figured it was some sort of low voltage 0-10 signal or something so I just moved on.
What you are describing the screen doing is common on them, lcd screen needs to be replaced. If you can get screen on its own it can be soldered in. Sensors work between 0.5 to 5.0 volts. Psv solenoids work on milliamps, sv solenoids work on 24 volts