Hi all, I'm at the end of my rope with this thing. It's a '99 773 with the electronic hand controls (ahc). Here's what it does: some days- works fine all day; other days- when I try to lower the bucket nothing happens, and then it will not lift/lower/tilt up/tilt down any more until I shut it off and then restart the machine. It is totally an intermittent problem, which is what is driving me insane. I have checked the actuators by removing them and switching them. It still happens only during bucket lowering so I believe I can rule that out. I have checked the hand control switches by swapping the plugs on them, and then the opposite switch makes it fail. Also, when I turn the machine on, the error lights to not function correctly. The left light (the indicator for lift) never turns on at all... ever. The right light remains on when the machine operates, and sometimes flashes (3 flashes) when the machine stops functioning. I have checked the connections and fuses several times, however, I still do not quite understand the wiring of it. Additionally, the previous owner hired a mechanic to troubleshoot this problem, who indicated that it is "probably the computer". At this point I believe he may be correct, but they seem to cost $1500 so that is the last resort attempt. I hope someone can help, as there is no dealer on this island.... Thanks.
Does anyone know a place I can find a used computer for this machine? Junkyards with bobcats, etc.? Thanks
UPDATE: Today I noticed a pattern. When the weather is bad ie cold and rainy- she works pretty good. When the weather is hot, dry, and sunny- she will absolutely refuse to function at all. Also I have found that the right error light sometimes blinks 3 times when it fails, and other times only 1 blink. Any ideas/ other people had this type of problem? I was ready to order the stupid $1500 computer, but now with the weather affecting it I'm not so sure... Grrrrrrr.
It seems like when I spray the interlock computer with water, it works for a while. I'm going to continue checking to see if that keeps working....
I see that you are located in Maui, how close to the water and prevailing winds? The reason that I ask is, salt and water is a very good combination for corrosion. If the connection is dry then high resistance due to the corrosion will prevent the proper voltages to reach the computer or switch or whatever. When you add water even a tiny amount will conduct some current. If it were mine I would take apart all of the connections and clean them well, some types of corrosion are hard to see but will prevent current flow. After cleaning apply a good coating of dielectric grease. This keeps the corrosion from reforming. Just a guess at your problem.
landshaper I had the same problem with my 773. Behind the side pannels I had to two leads with plugs laying on the bottom, both were covered by mud. I really don't know what there for, I didn't even know they were there until I started cleaning the mud out. I was getting lift and tilt errors all the time. I would have to shut it off and start it back up and it would start working again for a little while, now, it does happen, but its very rare. I got this info from a guy in Florida who was having the same problem with his 773. I sure hopes this helps.
My 773 f-series, hand and foot controls, had this problem and I replaced the bics solenoid and stem on the side of the control valve body and it fixed the problem.
Thanks for all the advice, everyone. So far I cleaned all the connections (every one I could find on the machine, even the fuses) with connector cleaner, that didn't help. Today she was extremely moody for the first half hour, then 6 straight hours without any errors. Grrr. I'm looking into the kit (on another thread) for $1000 to replace everything, and I am also considering switching to foot controls. Billg- I am about a mile from the ocean on the windward side of the island- so yes, it's the ideal recipe for corrosion. Also in a previous life my 773 pushed snow in Alaska- just as bad. Unfortunately when I cleaned all the terminals I couldn't find any corrosion. Tgeger- I did not find the connectors you mentioned... by side panels do you mean the drive motor access panels in the belly? Or somewhere else? DukeyJoe- how do you have hand and foot controls? I'm not familiar with that configuration, but did your bics solenoid test bad? Or did you just try a new one and it worked? Thanks again- it's very helpful to have some outside advice.
UPDATE: While the machine still intermittently operated normally, I have grown frustrated with her moodiness. I finally ordered the upgrade kit. It comes with a new ahc computer and both complete joystick levers for about $1000. Got it from tri-state bobcat, who was very helpful and they somehow managed to order it and get it to me in hawaii in a little over a week (very impressive). I installed it today, it only took about an hour- so far so good. Hopefully my next update will be positive.....
...Nope. The problem persists. Grrrrr.....
Could you clarify what you're saying, which error lights are you referring to, the LED lights on the BICS display? At the moment when it stops operating, and you get the three flashes on the "right light" (?), do you get beeps as well? If so, it should have a code that you can bring up on the hour meter display, might help narrow down your search field. I've never worked on one with Advanced Hand Controls (AHC) so I have no real experience to offer. However, I see you've been dealing with this problem since April and I know I would like to get it resolved, especially since there's no Bobcat dealer on that Island to help, hopefully one of the Bobcat techs here at HEF can noodle this one out. But it sounds like you've done simple tests to indicate that neither the hand controllers nor the actuators are the problem, so that leaves you with either a problem in the harness, the ECM, the ACS control module, various connectors, or ground connections. If it were me, and I continue to get no resolution for the problem, I would start taking that thing apart. Raise the cab and lock it off on the safety prop, remove the cover panels that are on the inside of the machine next to your left foot and right foot, and remove that entire panel in the center, the panel where the fuse box and control levers are located. I'd bust that thing open so I could get a good look at all the electrical harness to look for rubbed or pinched spots, take apart every connector and inspect the pins and sockets looking for anything suspect. And since you're in an area with little to no support, I'd consider purchasing the service manual for the machine because it will have the electrical diagrams (as well as other info) that will be useful to you. BTW, what series is your 773, and what is the machine S/N?
sounds like the BICS check valve is not holding pressure between the inlet and the BICS solenoid. Or the screen on the check valve or the screen around the BICS solenoid valve is plugged. That check valve is important when lowering the boom. Because lowering takes no pressure, system pressure drops to near zero. Well, obviously near zero can't unlock the lock valves (that takes 125 psi), so the lock valves lock. The check valve prevents that scenario by trapping oil in the passage across to the BICS solenoid in the DCV.