Komatsu Excavator PC128-UU Boom Hydraulic Problems Serial number 19XX. This has been sitting for about 3 months. Today I went out and fired it up. It started right off. but there was a constant beeping. The oil, coolant and hydraulic are all OK. I figured it had to be something else. After it warmed up some, I attempted to move it around to see what the problem was, and here is what I discovered: It shows a code 37. When it is just beeping: The blade goes up and down. It travel forward and reverse. It swings left and swings right. The boom goes down, but it DOES NOT go up. The boom extends out, but it DOES NOT come in. The bucket opens and closes. The thumb works both ways, but occasionally sticks and kills the machine (but this is not a new problem, it did it last fall). When I pull the override switch, the beeping stops, but there is a constant buzzer sound, and: The boon extends out AND back. The boom goes down AND up. All other functions also work. Any ideas what it could be or where to start. Could the cold weather (it only got down to about 5 degrees here), have anything to do with it? Thanks in advance. Pat
sounds like ice in the boom position sensor to me. I'd get it into a heated shop for 24 hours see if it goes away, if so follow up with a hydraulic flush and change filters/fluid. mine dose this every winter unless we have fresh oil and filters
I'm guessing the boom is articulated in the middle. If so you have the cab safety system locking you out. The system is there to prevent the bucket from hitting the cab when articulated all the way to the left. The bypass switch will enable to the boom to articulate far enough to the left that the bucket could hit the cab. The buzzer is a warning that you are operating the machine with a dangerous condition. There are potentiometers on each joint. You will see a wire harness connector for each potentiometer. Make sure all the connectors are intact and don't have any corrosion. I don't find a code 37 in my old notes. There is a code 31 which says defective boom potentiometer system.
Thank you for your information. I need to update. After giving this problem a lot of thought, I did remember that when I bought the machine I was told that one of the sensors was not working properly, but that it did not hinder to operation of the machine. I also remember the previous owner mentioning something about the override switch (he called it the emergency switch). Anyway, as I stated earlier in my previous post, when I pulled the toggle switch back on the override switch, the boom functioned properly, but the beeping continued. I kept thinking about this, and remembered that when I bought this, the toggle was held in the back position with a tie wrap. I went and checked, and the tie wrap had come loose. I secured it back, started the excavator, and NO beeping, and the boom works perfectly. So, my question is: what sensor would cause the boom to not work properly, and is it an easy fix? Also, what are the consequences of running it this way? I never plan on using the articulated boom. Thanks. Pat