Makers Acres
Well-Known Member
So here’s a little background: I hope that my experience can help someone or shed some light on a very frustrating issue. It’s a long read but if you’re having issues with your Bobcat it might help!
Over a year ago my buddy started having problems with his Bobcat A300. Sometimes it would work, other times the controls would never unlock. It seemed to be completely random. It would sometimes happen when you were right in the middle of working, and it would just freeze. If you were lucky, you could get it work right again, other times it would take days before you could get it to move.
Just to be clear, it would start-up, and then when you push the “Press to operate loader” button, you would hear a couple of clicks and nothing would happen.
After diving into the problem, I was able to get a copy of the service manuals and learned all about the codes and how to check them.
The loader seem to mostly show the following:
38-04 No communication from joystick controller
39-04 Left joystick no communication to Bobcat controller
40-04 Right joystick no communication to Bobcat controller
We called Bobcat out, and they sent us a tech. He spent about 20-30 minutes on it and could not find the problem. The machine started right up and worked fine for him, of course.
He seemed to think it was a wiring problem. He said they could take it back to their shop and they would start
exploratory work, beginning with replacing the wiring harness (for a couple grand). Needless to say, we did not pick that option.
I printed up the wiring diagrams on 36”x48” paper and started tracing out all the wires, and testing them all for continuity. I also traced each wire back to make sure it had not been chewed up by rodents.
I did not find anything wrong, and we went back to the bobcat dealer. They told us it was probably the joysticks themselves, and they wanted to swap them out (for $5K!) to the newer upgraded style. I was told the joysticks on this model had a lot of problems and Bobcat quickly phased these style joysticks out. Once again we said no.
Months went by, the machine limped along and was occasionally usable, and I this was really burning me up inside that I couldn’t solve this.
I pulled the control board out and put it on my bench, and built a small wire harness for testing. I connected it to a power supply and looked at all the pins, checking them for voltage and proper grounding. All seemed fine.
I even connected the CANbus pins and looked for control message on my scope. My scope was detecting the message, so the joystick controller seemed fine. I then pulled out the Main Controller and did the same. This seemed to pass too. I put everything back together and it STILL did not work.
I then moved onto the joysticks: I pulled the first one apart and learned the hard way that they were boobytrapped. The have a strong spring, and when you try and remove the top without clamping that spring, it rips the flexible PCB apart. In my case it broke the connecting wires going up to the handle, and broke one of the X/Y position sensors off.
It took another week to fix this manually, and a lot of patience to get the board rebuilt correctly and get the sensors back in the right places.
Once I got past this, I could see the CAN messages from the joysticks, and I could see the analog X/Y signals coming from the joysticks.
Then in a stroke of good fortune, I went back to the joystick controller and while observing the CAN message, they suddenly stopped. Then they started again, then dropped out again. WHAT?? I pushed on the center of the joystick controller, and the messages stopped again. I did this for a while till I could repeatedly put forces in different spots and start and stop the messages consistently.
I reinstalled the joystick controller back in the machine and was able to put a couple of folded up napkins behind the center of the controller and just use the outside two bolt holes to put the board slightly under tension and flexed.
Crossed my fingers and the machine started right up and WORKED!!! WHAT THE HECK.
We ran it for a few hours and it was working the best it had in a year. We ran it for about a month like this and all was running great. My guess is that a solder trace on the board failed. Sadly these boards are potted in EPOXY, so it is next to impossible to get at the components.
My buddy found a new controller online and ordered it. Part number 6683608 by the way, and I think it was around $1200 for it. We got it and swapped out the controller with the new one.
It started right up, and you have to go through a couple of calibration things to get it setup. The first one you can put up on blocks and it does a flow or wheel speed calibration. This one was pretty easy but took a couple of times to get it right. The next is you have to connect to bobcat service software and I think you have to calibrate the turning sensors. Since we could not do this, we just ignored the error asking for calibration (it didn’t stop the machine from working).
The machine ran for about a month and then hard stop.
The joystick controller failed and started showing “38-04 No communication from joystick controller”.
I pulled the controller out and connected it to my scope, and sure enough, the CANbus was dead and was not showing any messages. We contacted the place we bought the controller from since it was warrantied for a year. The said since we didn’t take it to an authorized service center, they voided the warranty of the board. Ugh!
So I guess my question here is if anyone knows if you ignore this calibration, does the controller have a limited number of runs without calibrating before it locks itself out? Could this be reset by a Bobcat dealer that knows what they are doing? I know my Dodge truck has a “Digital Fuse Box” that if it thinks something is wrong, it disables that component and you need a Dodge Services tech to reset it. Very frustrating, considering we thought everything was peachy!
TLDR: Busted Controller board, swapped it out, now got a busted Bobcat.
Over a year ago my buddy started having problems with his Bobcat A300. Sometimes it would work, other times the controls would never unlock. It seemed to be completely random. It would sometimes happen when you were right in the middle of working, and it would just freeze. If you were lucky, you could get it work right again, other times it would take days before you could get it to move.
Just to be clear, it would start-up, and then when you push the “Press to operate loader” button, you would hear a couple of clicks and nothing would happen.
After diving into the problem, I was able to get a copy of the service manuals and learned all about the codes and how to check them.
The loader seem to mostly show the following:
38-04 No communication from joystick controller
39-04 Left joystick no communication to Bobcat controller
40-04 Right joystick no communication to Bobcat controller
We called Bobcat out, and they sent us a tech. He spent about 20-30 minutes on it and could not find the problem. The machine started right up and worked fine for him, of course.
He seemed to think it was a wiring problem. He said they could take it back to their shop and they would start
exploratory work, beginning with replacing the wiring harness (for a couple grand). Needless to say, we did not pick that option.
I printed up the wiring diagrams on 36”x48” paper and started tracing out all the wires, and testing them all for continuity. I also traced each wire back to make sure it had not been chewed up by rodents.
I did not find anything wrong, and we went back to the bobcat dealer. They told us it was probably the joysticks themselves, and they wanted to swap them out (for $5K!) to the newer upgraded style. I was told the joysticks on this model had a lot of problems and Bobcat quickly phased these style joysticks out. Once again we said no.
Months went by, the machine limped along and was occasionally usable, and I this was really burning me up inside that I couldn’t solve this.
I pulled the control board out and put it on my bench, and built a small wire harness for testing. I connected it to a power supply and looked at all the pins, checking them for voltage and proper grounding. All seemed fine.
I even connected the CANbus pins and looked for control message on my scope. My scope was detecting the message, so the joystick controller seemed fine. I then pulled out the Main Controller and did the same. This seemed to pass too. I put everything back together and it STILL did not work.
I then moved onto the joysticks: I pulled the first one apart and learned the hard way that they were boobytrapped. The have a strong spring, and when you try and remove the top without clamping that spring, it rips the flexible PCB apart. In my case it broke the connecting wires going up to the handle, and broke one of the X/Y position sensors off.
It took another week to fix this manually, and a lot of patience to get the board rebuilt correctly and get the sensors back in the right places.
Once I got past this, I could see the CAN messages from the joysticks, and I could see the analog X/Y signals coming from the joysticks.
Then in a stroke of good fortune, I went back to the joystick controller and while observing the CAN message, they suddenly stopped. Then they started again, then dropped out again. WHAT?? I pushed on the center of the joystick controller, and the messages stopped again. I did this for a while till I could repeatedly put forces in different spots and start and stop the messages consistently.
I reinstalled the joystick controller back in the machine and was able to put a couple of folded up napkins behind the center of the controller and just use the outside two bolt holes to put the board slightly under tension and flexed.
Crossed my fingers and the machine started right up and WORKED!!! WHAT THE HECK.
We ran it for a few hours and it was working the best it had in a year. We ran it for about a month like this and all was running great. My guess is that a solder trace on the board failed. Sadly these boards are potted in EPOXY, so it is next to impossible to get at the components.
My buddy found a new controller online and ordered it. Part number 6683608 by the way, and I think it was around $1200 for it. We got it and swapped out the controller with the new one.
It started right up, and you have to go through a couple of calibration things to get it setup. The first one you can put up on blocks and it does a flow or wheel speed calibration. This one was pretty easy but took a couple of times to get it right. The next is you have to connect to bobcat service software and I think you have to calibrate the turning sensors. Since we could not do this, we just ignored the error asking for calibration (it didn’t stop the machine from working).
The machine ran for about a month and then hard stop.
The joystick controller failed and started showing “38-04 No communication from joystick controller”.
I pulled the controller out and connected it to my scope, and sure enough, the CANbus was dead and was not showing any messages. We contacted the place we bought the controller from since it was warrantied for a year. The said since we didn’t take it to an authorized service center, they voided the warranty of the board. Ugh!
So I guess my question here is if anyone knows if you ignore this calibration, does the controller have a limited number of runs without calibrating before it locks itself out? Could this be reset by a Bobcat dealer that knows what they are doing? I know my Dodge truck has a “Digital Fuse Box” that if it thinks something is wrong, it disables that component and you need a Dodge Services tech to reset it. Very frustrating, considering we thought everything was peachy!
TLDR: Busted Controller board, swapped it out, now got a busted Bobcat.
