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Bobcat 763 Electrical, Gauges come on 1 second, Then says Input

Discussion in 'Skid Steers' started by Bobcat Crazy, Mar 14, 2020.

  1. Bobcat Crazy

    Bobcat Crazy Well-Known Member

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    I have most of this 763 back together. I am now trying to crank it but, when I turn the key on the gauges and panel lights come on for one second, then everything goes off and the (Input) light comes on for about 5 seconds and then nothing else works. I can then cycle the key again and it repeats.

    I have new battery cables on it, positive and negative so the cable connections are good at both ends, the battery voltage checks good.

    Could any of you point me in the correct direction? I don't have a clue where to start as electronics are my weak point.

    All help is appreciated!
    B-Crazy
     
  2. willie59

    willie59 Super Moderator

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    I don't have an answer for you, nor do I know what all can cause that fault, but one thing I know can cause that fault is a direct short of a power wire that comes from the main controller. For example, had an S205 do that once, I searched all over that machine looking for the cause. Found one of the wires in that bundle that goes down the left loader arm to the attachment plug in connection was pinch and grounding to the loader arm. That power wire came directly from the main controller. My guess was the main controller was seeing this short circuit on power up, and since it had no way to "lock out" that particular circuit it simply shut down to protect itself, Input comes up in display because that means there's no communication with the main controller and the BICS panel. Of course not, it shut itself down. All I can suggest is go over the electrical system well looking for bad spots, even disconnect harness plugs where you can, such as the loader arm attachment harness, there's typically a plug connection where that harness connects to the main frame harness. Unplug it and try power up again. If you can't find the problem you'll most likely have to get a Bobcat tech out there to find that gremlin.
     
  3. Bobcat Crazy

    Bobcat Crazy Well-Known Member

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    Thanks, W59! I am always amazed at not only the depth of knowledge you guys have but, also your willingness to give of your time to help others like me as we try to work through these issues.

    Many thanks!! :)
    B-Crazy
     
  4. Bswwood

    Bswwood Active Member

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    This is from the manual, might help. usually the "9000" wires are purple communication wires. The 763G will be RX/TX communication.

    Typically an Input error is caused by a failure with the 9100 wire from the Main controller to the 9110 and 9120 wires at the panels.

    Check the wires for continuity and a short to ground.

    *If there is no continuity, check the cab to mainframe connector for a loose or pushed back pin.

    *If there is continuity from the panels to the main controller, check the wire connections at the panels and main controller for loose or pushed back conditions.

    *If there is a short to ground, disconnect the cab to main harness to see if it is on the cab side or the main harness side.

    *The Left hand panel can also cause the "input" code.

    *A Bobcat Controller failure can also cause an "Input" error.



    NOTE: If dealing with an electrical problem on a 763 G series loader be sure to check the Bobcat Controller, see the solution below.



    Check that the Cab Seat Pan Foam is not contacting the Heat Sink on the top of the Bobcat Controller, this can be detected by raising the cab and looking for an indentation in the seat pan foam caused by the Bobcat Controller Heat Sink. The Bobcat Controller may be damaged due to the interference. If interference is detected remove that section of foam, there should be a perforated cut out in the foam remove this perforated cut out before installing the replacement Bobcat Controller Note: Be sure that the Wiring Harness also does NOT contact the Heat Sink. Reroute if necessary.
     
  5. Bobcat Crazy

    Bobcat Crazy Well-Known Member

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    Hey, you Guys are an awesome resource, this will give me a lot of info to work with. Hopefully, I will get the time tomorrow after work to see if I can locate the issue.
    As soon as I have time to work on it I will update you Guys.
    Thanks for such great info!:)
    B-Crazy
     
  6. Bobcat Crazy

    Bobcat Crazy Well-Known Member

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    Okay Team, I have found the issue, thanks to the posting from the book (thanks BSWWOOD). The 9100 wire has no continuity to the 9110/9120 wire at the two upper panels.

    I do have continuity on the 9110/9120 wire which runs from the left panel to the right panel. I found a diagram online which shows this wire, it is numbered 9110 on the left panel and the other end of this same wire is numbered 9120 at the right panel but it is the same wire.

    The diagram shows the 9100 wire connecting to this wire somewhere but does not say anything about where the joint/connection might be located in the wiring harness. Do any of you Guys know where this connection might be located in the wiring harness?

    The only way I know to find it is to start cutting the mesh wiring harness cover until I find the connection. I certainly would hate to do that.

    If any of you have an idea where to start looking for that joint it would be much appreciated.

    It looks like I am closing in on this issue and it is all because of the help you Guys have offered! Thanks so much Guys!!
    B-Crazy :D :cool:
     
  7. willie59

    willie59 Super Moderator

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    I've never had to search for that wire junction so I don't know where it's at. But I do know if you have no continuity from wire 9100 at the C408 connector with wires 9110 and 9120 at the left and right panel then that's for sure a problem.
     
  8. Bobcat Crazy

    Bobcat Crazy Well-Known Member

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    Thanks w59, it is good to know that I am on the right track! :)
     
  9. willie59

    willie59 Super Moderator

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    Something to consider other than that (where is it?) connection of 9100 wire at C408 and the 9110 and 9120 wires at the panels. Back at the C408 connector, I once had a T300 rental machine that was about to drive me bat $hit crazy. Machine would work flawless for day after day, then all of a sudden, nothing. Every time the customer would call me about that dead machine, I'd show up, it would work perfect. Bang head. Kinda hard to fix something that ain't broke. Finally a day came it was dead when I got there. Found there was no power on the 1900 computer power wire coming out of the C408 connector. It was getting power on the input side of the connector, but nothing coming out. Pins and sockets inside the connector looked fine, but they damn sure weren't no power coming out of C408 on wire 1900. Being out in the middle of nowhere my option was to connect a jumper for wire 1900 from the input side of C408 to the output side. Machine came to life. My point, in your case, find wire 9100 on the output side of C408 connector and either probe it or strip it open to check continuity between it and the 9110 and 9120 wires at the panels. You need to eliminate a possible problem at the C408 connector before you start search for that junction of 9100, 9110 and 9120.
     
  10. Bobcat Crazy

    Bobcat Crazy Well-Known Member

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    Good morning W59 (and the rest of you Guys helping with or following this thread), I hope all of you are doing well in these crazy times. Keep your chin up, this too will pass!

    Back to my issues with the 763. Once I found the wiring diagram online and using the info you Guys had provided I started tracing the 9100 wire. I unplugged the J2 connector at the computer and the C408 connector and pinned the terminals to test the wire.
    (I also found trace marks of probing on the 9100 wire so someone that knew some of the great info you Guys have shared with me had already been looking for this issue).
    I do have continuity from the J2 to C408, I do not have it from the other side of C408 to the connectors at the left or right upper panels.

    When I get back to it (hopefully Monday after work) I will probe the 9100 wire leaving C408 and pin test the terminal on the upstream side of C408 to make sure it is not a bad connection between the terminal and the wire. If that is good, it only leaves the hidden connection somewhere inside the wiring harness where 9100 connects to the 9110/9120 wire.

    While I was thinking about how to find the hidden connection I may have come up with a way to find it. I know when the telephone tech comes to work on a communication wire issue in our 5 story building he hooks a tone generator on one end of the suspect wire and he can trace that tone on that wire from communication room to communication room until he finds the bad connection. If the (tone generator device and tone reading/finder device) will work from floor to floor on a large building, then it stands to reason that it would work on this wiring harness for just a few feet. I have a friend that has one of these tracing tools that I can barrow.

    So if this works I will be able to cut the mesh wiring harness covering where the tone ends and repair the bad connection without having to cut more of the mesh than is necessary. Should all of this work the way it works in my mind (admittedly my mind is a strange thing and everything does not work in the real world as it does in my mind:confused:o_O:D)!!! I will be able to share with all of you where this hidden connection is.

    I would be so happy to contribute something to this site that could possibly help someone else (at some point) that may have this same or similar issue in the future. I have gained so much helpful info from all of you and it is greatly appreciated. Must of you Guys are people that have been in the trenches with these machines and have "been there done that" and your knowledge of these machines and different issues they present is priceless.

    I am an old country boy that loves to turn wrenches (and I must not be smart enough to realize that I am not supposed to be able to fix these machines without any formal training :eek:) but your help has made all of my endeavors on these machines successful. These projects have caused me to do a lot reading your posts, searching the Forum, and eliminating one possibility after another until the cause was actually found.

    I thought that one day I would be smart enough to not jump on projects that I don't know anything about and have no training in. Well, I will be 60 in a couple more months and obviously, I have not gotten smart enough to stop doing this type of stuff!! :confused::eek:o_O:D

    Thanks again Guys for your time and replies!!!

    B-Crazy
     
  11. Ronsii

    Ronsii Senior Member

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    The tone 'detector' you are thinking of is called an induction amplifier... one of my favorite tools to track down stuff :) you can use it with just one wire also.

    induct-amp-set.jpg
     
  12. Bobcat Crazy

    Bobcat Crazy Well-Known Member

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    Yes that is the same exact tool that my friend has. I didn't remember what it was called but you nailed it! Thanks
     
  13. Bobcat Crazy

    Bobcat Crazy Well-Known Member

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    Okay Guys,
    Here is the latest on the 763 and it is not good news. I traced and tested all of the wires from the J2 plug on the controller to the left and right panels up top and they all checked good.

    I had posted earlier that I did have a connection on the 9100 to 9110 and 9120 at the upper panels but I had to have just not had a good connection with one of my test leads because it checks good now and I have checked them all several times now.

    When I was SURE that all of the circuits checked out good I continued to dig deeper and took the controller apart and there I found the bad news :eek::eek: at least 2 burned places in the circuit board :( sometimes I just can't get a break o_O but I can certainly get a Brake :mad::mad:!!

    Is there any help to be found with an issue like this? Or would the only answer be to buy a new controller/circuit board?

    And yes I am very afraid of what I think the answer will be but I have to ask it anyway :(:(:(!

    There are not enough sad emojis available for me to express how this new find has made me feel :(!

    All help would be appreciated even if it is a link to where I might find the most reasonably priced replacement.

    Please see pics below for controller part and serial numbers and the number on the actual circuit board inside the controller housing.

    Thanks,
    B-Crazy
    763 controller part number.JPG 763 controller circuit board number.JPG
     
  14. willie59

    willie59 Super Moderator

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    Looks like the seal for that controller has been compromised for some time allowing moisture to get in there. To my knowledge, and I could be wrong, but the only place I know to get a replacement controller is Bobcat. And even if you found another source you'd still have to get a Bobcat tech out there to program it for your machine. I know that prolly ain't what you wanted to hear, but unfortunately that's the way it is.
     
  15. Ronsii

    Ronsii Senior Member

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    So.... what's burn't on the board? or is it mainly the part just out of frame lower right??
     
  16. Bobcat Crazy

    Bobcat Crazy Well-Known Member

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    Okay, I don't know if I can do this justice or not but I will try.

    This pic shows a wire that has been soldered in over one of the burned circuits (I'm not saying who soldered that wire in but it may have been that B-Crazy guy ;)!

    763 circuit board.JPG
    This next pic shows where the wire goes through the CB and this end is connected to the other solder point which the printed circuit went to before it was burned out. Hey I know it is not pretty but it might work :eek:!

    763 circuit board 1.JPG

    This shows there is another very small printed circuit that is burned in to.

    The next pic will show where the other end of this circuit is connected but the solder points are so small I can't solder them without shorting it to another circuit :mad:

    circuit board 4.JPG

    This pic shows where the other end of this very small circuit is connected but again too small for me to solder.

    circuit board 5.JPG




     
  17. Bobcat Crazy

    Bobcat Crazy Well-Known Member

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    Here is a place close to the other end of the board that looks like it is corroded I am not sure if they are making connection or not but they may be. the small circuits look to still be intact however I am viewing all of this through a magnifying glass.

    763 board.JPG

    If you flip the board over from the pic above the corroded section is located between the red (capacitor I Guess it is) and the hole where the J3 connector bolt would be in pic below. Just to the left of the red capacitor.

    763 circuit board 2.JPG

    Does this give you some idea of the areas I am dealing with? I hope I did a fair job with the pics and discription.
    Thanks for any help anyone can provide.
    B-Crazy
     
  18. Ronsii

    Ronsii Senior Member

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    For bridging very small lines there are a couple ways to do it...

    1:remove the coating and burnish with a fine steel wool then mask where you don't want to solder to flow with a resist pen/paint/tape and flux the area then swipe a good tinned iron across it with a small amout of 60-40 solder on the tip

    2:remove the coating, burnish then draw the area with a conductive silver solder pen, done.

    3:find the ends and jump around them... like you did with the wire ;)

    4:*BEFORE* you do any of these it is important to find out why the trace burnt!!!! because the burnt trace more than likely acted as a fuse and saved other components....(or not :( ) So it's best to trace and identify just where the circuit goes and comes from and then determine if the cause has been fixed if it was a short or just corrosion causing a short....
     
  19. Bobcat Crazy

    Bobcat Crazy Well-Known Member

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    Thanks Ronsii, that is great info! I am ordering the silver trace pen tonight, the link to it worked good too so I didn't have to search amazon for it.

    All you Guys are totally awesome with all of the experience you have and the help like this that you offer. Now I am interested to see if I can actually for this CB! I would have never thought of a fix like this. I had never heard of this type pin or knew that a CB could be fixed this way. :):)

    Thanks Guys!
    B-Crazy :D
     
  20. Ronsii

    Ronsii Senior Member

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    Have you got any ideas why the board shorted??? or do you think it was just from the corrosion and gunk in there??? I would try to identify where those connections go and make sure you don't have wiring harness issues or something else outside the CPU that might have caused some of the problems...

    On the pen, that was just a quick links I put in there to let you know the alternatives were out there normally I get that kind of stuff from an electronics clearing house or digikey... or ebay...etc...