873c Auxillary hydraulic issues

[mechdriver]

First, thanks to all the post on here about aux hydraulic issues, I've learned a lot but still have an intermittent problem. I've replace both rod and base coils and cartridges and the right lever control, that totally failed. the aux hydraulics will come on but, momentary light on, and works but will stop and the momentary light or the detent light will flash, which way the switch was pushed. I can cut the machine off and switch the key to the bleed position and most of the time it will start working again when I crank it and press the mode switch. Any suggestions as to what may be causing this intermittent issue? Thanks

 

[7LBSSMALLIE]

aux control mod lft hand firewall . alittle below steer console . two connectors 4x4 square, alum box.

 

[7LBSSMALLIE]

aux control mod lft hand firewall . alittle below steer console . two connectors 4x4 square, alum box.

you have not uptadeted as to issue is resolved . makes it kind of hard to give a crap about next poor guy. hence the reason I no longer check daily.

 

[mechdriver]

you have not uptadeted as to issue is resolved . makes it kind of hard to give a crap about next poor guy. hence the reason I no longer check daily.

Problem not solved. Downloaded repair manual and spent last Saturday checking voltages on the PWM and could not identify any issues. Still fails periodically. When i got done with all the static checks Dat. It worked fine for nearly 20 minutes. After it tripped out the first time it was about every minute. If i bleed hydraulics whem i shut it off it seems to come back to life for a little while but i just got on it and it wouldn't work to start with. Im realy not sure which way to go with this thing except the local dealer. As far as me not responding immediatly, thanks for the suggestions but i don't live on the internet.

 

[Tazza]

Problem not solved. Downloaded repair manual and spent last Saturday checking voltages on the PWM and could not identify any issues. Still fails periodically. When i got done with all the static checks Dat. It worked fine for nearly 20 minutes. After it tripped out the first time it was about every minute. If i bleed hydraulics whem i shut it off it seems to come back to life for a little while but i just got on it and it wouldn't work to start with. Im realy not sure which way to go with this thing except the local dealer. As far as me not responding immediatly, thanks for the suggestions but i don't live on the internet.

Sadly i don't get on here as often as i should either, thanks for the update when you got time.
The only other thing i can think of is a wire rubbing on the frame. You have replaced all the parts i'd do too. If it works and fails with a flashing error, it makes me think there is a wire that could be rubbing some where shorting out and causing the error.
The big issue is where to look? You have the wires from the right control lever back to the control module, then you have from the module to the coils.

 

[mechdriver]

Sadly i don't get on here as often as i should either, thanks for the update when you got time.
The only other thing i can think of is a wire rubbing on the frame. You have replaced all the parts i'd do too. If it works and fails with a flashing error, it makes me think there is a wire that could be rubbing some where shorting out and causing the error.
The big issue is where to look? You have the wires from the right control lever back to the control module, then you have from the module to the coils.

I've checked all the wiring and if there is a break or bare spot l can't find it. I've unplugged, cleaned and reconnected every connector that i can find and checked all ground points l can find. Still fails. Can the PWM be intermittent? Could it be hydraulic in nature? Overpressure? Bypass valve sticking?

 

[Tazza]

I've checked all the wiring and if there is a break or bare spot l can't find it. I've unplugged, cleaned and reconnected every connector that i can find and checked all ground points l can find. Still fails. Can the PWM be intermittent? Could it be hydraulic in nature? Overpressure? Bypass valve sticking?

As you are getting a light flashing code, i would not think it is hydraulic..... I guess it could be the controller, electronics can do weird things, especially in earth moving gear being in the elements shaken about.
There really isn't much else to look at, you have done wiring and connectors, new coil and stem.
I guess, another long shot is the control switch in the handle, but the will not be cheap, and you never know if it is at fault either.

 

[mechdriver]

As you are getting a light flashing code, i would not think it is hydraulic..... I guess it could be the controller, electronics can do weird things, especially in earth moving gear being in the elements shaken about.
There really isn't much else to look at, you have done wiring and connectors, new coil and stem.
I guess, another long shot is the control switch in the handle, but the will not be cheap, and you never know if it is at fault either.

I failed to mention that I did have to replace the joystick head. Thumb switch/rheostat died while I was working on everything else. I've called a local repair guy and he is going to take a look at it at first opportunity. Does anyone know what the going price for a replacement PWM is? As soon as I have a cure, I'll post the results.

 

[Tazza]

I failed to mention that I did have to replace the joystick head. Thumb switch/rheostat died while I was working on everything else. I've called a local repair guy and he is going to take a look at it at first opportunity. Does anyone know what the going price for a replacement PWM is? As soon as I have a cure, I'll post the results.

You have replaced just about every part associated with it.... The computer is about the last part.
Sadly, i thought the box was expensive, unless yours is the style that is not in the main brain box and uses a small unit mounted to the frame that controls the aux and i think parking brake.

 

[mechdriver]

You have replaced just about every part associated with it.... The computer is about the last part.
Sadly, i thought the box was expensive, unless yours is the style that is not in the main brain box and uses a small unit mounted to the frame that controls the aux and i think parking brake.

Thanks for everyones help. I finally broke down and ordered the PWM control box. My machin is back in action.????

 

[mechdriver]

You have replaced just about every part associated with it.... The computer is about the last part.
Sadly, i thought the box was expensive, unless yours is the style that is not in the main brain box and uses a small unit mounted to the frame that controls the aux and i think parking brake.

Thanks for everyones help. I finally broke down and ordered the PWM control box. My machine is back in action.????

 

[Tazza]

Thanks for everyones help. I finally broke down and ordered the PWM control box. My machine is back in action.????

Glad it's fixed, shame it was the box..... I'd like to get my paws on one and see just what is inside to see if they can be fixed or not, i'd like to think the outputs aren't too complicated and have common failure points and not be the main control chip that stops working.
There have been a few failures of these modules recently on the forum, could be due to heat i guess

 

[mechdriver]

Glad it's fixed, shame it was the box..... I'd like to get my paws on one and see just what is inside to see if they can be fixed or not, i'd like to think the outputs aren't too complicated and have common failure points and not be the main control chip that stops working.
There have been a few failures of these modules recently on the forum, could be due to heat i guess

I'm actually guessing it's a combination of heat and vibration. since the circuit board is completely covered in epoxy it would be very difficult to remove the 'protecting' layer to get to the components. Back in the late 80's I worked in an electronics repair shop and we did, at times of necessity, grind into potted circuits for repair. It was always a time consuming gamble and really not feasible except as a last resort. On the other hand, I have a faulty unit I would be willing to sell for a nominal fee if anyone would like to try. Thanks again for all the help.

 

[Tazza]

I'm actually guessing it's a combination of heat and vibration. since the circuit board is completely covered in epoxy it would be very difficult to remove the 'protecting' layer to get to the components. Back in the late 80's I worked in an electronics repair shop and we did, at times of necessity, grind into potted circuits for repair. It was always a time consuming gamble and really not feasible except as a last resort. On the other hand, I have a faulty unit I would be willing to sell for a nominal fee if anyone would like to try. Thanks again for all the help.

Glad you have done it before, you know all the little things to check first.
Thankfully i haven't tried messing with potted gear very often, i did it years ago just out of curiosity. As i got the epoxy off components, i also removed numbers from the components, so it wasn't really helpful..... But as a kid, you still have to try