Yesterday I looked at old threads to solve my lockup problem with a Case 9020B excavator (early model) but didn't find any solutions. Engine starts up fine, but there's no auto throttle control with the rheostat, and all hydraulic movement is locked. In the WORK MODE display, the message "mode" keeps flashing. (When I turn off the key, the engine quits, but "mode" keeps flashing forever unless I also turn off the battery disconnect switch which I have on the negative side of the battery.) First thing, checked the limit switch in the left console, but it works fine. At the rear of the right console is the self check controls, and pressing any of those buttons produces nothing on the dash display. (I assume the display is working, but not positive.) To the left of the self check controls is the throttle "backup" button. When I press it, I not only can manually control the throttle, but the whole machine becomes unlocked, operating normally, it seems, except for the auto throttle control. I figured I would find a bad relay behind the controller behind the seat, but they all seem to be good (switching them around). Page 13 of section 4001 (electrical) tells me that a controller defect will produce this situation of no auto throttle but has manual throttle. So I figure maybe the controller in back of the seat is bad. The little window of it shows both the green light on and red light on. Anybody know what this means? I also took the board out, and it looks as good as new, as well as perfectly clean. No burnt out elements, etc. Hard for me to figure the board is bad, looking this good. Plus a new board ain't cheap, maybe $1500 to $2200 on the internet. And once installed you can't give them back. I read other posts, where someone had the problem with a dirty element in the filter of the pilot control solenoids for the hydraulics in the right rear compartment, causing a lockup. But replacing the filter didn't help. Also checked the three fuses in the left rear on the wall behind the batteries--they're working. I've checked a lot of electrical connectors but haven't found any problems. Any ideas, or courses of investigation? My first-born's name is up for grabs.
Ok .. have a 9030B with some of the same symptoms .. replaced the throttle motor .. replaced the computer .. just to find out it was the RPM Sensor .. I got that advice early but didnt listen .. good luck
Thanks for the reply. Any advice on how you check that sensor, and where is it? Talked to Case yesterday, and an old head told me a number of sensors could cause the problem.
I have a 94 case 9020 and my throttle motor quit on me , i was just seeing if you had to go to case to get the motor or is there other places you can find them , case wants $1000 , thanks !
Reply Sorry, but I don't know. My problem turned out to be the computer, which I apparently burned when jumping the battery. Expensive item, that computer.
do you have your old computer and if so what is the KHR number on it. I took my computer to a board repairer and was charged over $700 and the board is locked on the red led. email me if you could...I have a linkbelt quantum 2700 and I apparently arced the computer while trying to start it.
I kept the old board, with the probably forlorn hope of cheaply fixing it one day to serve as a backup. On the outside of the metal container, there's this number, which is probably what you're asking about: SMCU-5 KHR1781. I never looked at the board itself, but Case in Wichita said one can see a burn on it, from a spike in voltage.
samperkins21 and dwayanehicks I have the exact same machine as sp21 and am going through the same thing right now!! Feel free to email me at jflan3 at aol dot com. Any help would be appreciated.
Not much I can add. Case looked at the computer closely and found a burn, and that was my only problem. So if you check yours, even with a magnifying glass if necessary, you might find your problem. A new one is expensive, but you can get a cheaper one cannibalized from an excavator that's been junked. Of course, you might be taking a risk with a used one.