Hi all, I have Kobelco SK250NLC-6 Serial: LL08 03036 Year 2000 Pre minor change. I need some help from someone that has in depth knowlege of electronic in this excavator. People in this post will probably be able to help: HeavyEquipmentForums Original problem was that machine was giving out errors: #16 - P1NEGA-CON SENSOR - known fault from before, replacement sensor on order. #30 - STEP MOTOR M CURRENT-NG #31 - STEP MOTOR M S/PT. ERROR Customer had to use manual throtle. I took motor off and repaired micro switch that wasn't making contact when motor goes to it's reference position. I installed motor back, but I wasn't able to get it working. It shuts the engine down when I turn the key to shut down, and moves to idle position when I start the engine. But when I turn the dial to raise RPM, it just sits at itde. I checked signal from dial to Controller and it has range of 0,5 to 4,5 VDC. Only error #16 remains now. Please note that is error was from earlier, it didn't come up at the same time as #30 and #31. Can someone confirm if A adjustment MUST be done, and if this is my problem? I also noticed that none of the buttons are working, including the one on the screen. Customer mentioned that this happened at the same time when he had a problem with throtle motor, I can't trust him 100% because lot of times he is giving me conflicting information, but let's say he is saying the truth, for now. Now this is stopping me from performing A adjustment, but also buttons must work. When I power up the machine, screen comes up with #16 error and I can't silence the buzzer or move to a different screen. I have checked all the connections OK. I think I have a problem between Controller and switch box assembly. There is some sort of serial communication going on there. Switch box has some multiplexer chips inside, so I think that controller is constatnly scanning the inputs to the box and dependent on the states it takes action. But nowhere in the manuals is this process described or how it can be checked. At first I had some loose connections on the CN14 of the controller, and wiggling the wires sometimes activated some commands, MODE A-M-B would change, wiper would come on, and so. But after repairing loose connections, nothing is working now. Connections are good, I have checked them and 100% sure that they are OK. When I let the machine on and I unplug CN14 and replug it or CN31 or 32 on switchbox assembly some action happens, but I think that is due to signals tansition due to plugging. On the box I have checked 5 volts Ok, ground OK, every button changes from 5 volts to zero when pressed. One interesting thing that I found was that input 32-9 when I take the wire out and reconnect, it changes my mode from A to M than to B and back A and so, every time I disconnest and reconnect the wire. But even with this wire disconnected, none of the buttons are working. I don't have a spare switch box so I can't change it. Does anybody have any ideas how to go futher about this? Thanks!
Pictures of the controller and switchbox
Hi an A-adjustment will have to be preformed if motor was removed or replaced but since the dash buttons are not working you can't preform it till that problem is fixed. When you turn the throttle dial from low to high idle and you said it does not move is this with just key turned on or with machine running and while working the levers. Is auto decel turned on or off?. Also have you confirmed p1 nega con sensor is faulty by plugging into the p2 connector to see if fault on screen changes to p2 nega con
It doesn' move when motor is running. It starts the motor, moves from shut down to idle position, but doesn't react to throttle dial. Auto decel on or off, same thing. but that makes me think, is auto decel circuit OK, I haven't checked that. I didn't try anything with P1 sensor yet. I know i need to fix that too before A adjustment, but I was focused on the buttons. Machine is working in manual mode and throtle for next few days because it is needed for work, but I'll get onto it after job is finished.
Hi all, Bit of an update. Pressure sensor is replaced, and auto throttle motor is installed. Buttons were working fine. A adjutment done. All OK. Now few days later, buttons don't work again. I come to chek, they are working, then all of a sudden they stop again. Does anybody know what sort of coding goes on between switch box and controller? Thanks!!!