Bob S185 locking up

[Jacksondemo2754]

Hi everyone. So I have another machine that's acting up. Anyone ever run into the service code D7555. In the manual it says right forward drive short to ground. It only does it intermittently. But it will lock up the forward drive on the right side but not the reverse side of the right side.

Thanks again

Nick

 

[crewchief888]

Hi everyone. So I have another machine that's acting up. Anyone ever run into the service code D7555. In the manual it says right forward drive short to ground. It only does it intermittently. But it will lock up the forward drive on the right side but not the reverse side of the right side.

Thanks again

Nick

assuming this is a SJC machine?


several things can cause that code,
bad drive coil
bad harness at the pump
bad connection from the pump harness to the mainframe harness.

probably the easiest thing to do would be swap the drive coils on that side, and see if the problem goes to the opposite direction. if it does the coil is bad, if it doesnt it's probably in the wiring or connection.

i think the fwd side drive coil is the coil on the rear, (closest to the engine), but off the top of my head i'm not sure.
disconnect one of them, power the system up, try to drive, and see what fault you get.

 

[Jacksondemo2754]

It is SJC. And my next question was going to be if the rear coils facing the engine were to drive the coward motion and vise versa. I'll check this out today. Thanks again

 

[Jacksondemo2754]

Ohh and by the way I did swap coils and the fault went away for awhile and then came back same code same side

 

[crewchief888]

Ohh and by the way I did swap coils and the fault went away for awhile and then came back same code same side

take a look at all the connectors, it may be something as simple as a loose pin or socket in the connector.

 

[Jacksondemo2754]

I took a look at the connectors. Tested for continuity and ohm they all tested good. Tested the main frame harness to the drive controller it tested good. The only time it happens is if you are going fast and you travel over excessive bumps and then it locks up and only forward right side won't move all the other functions for movement operate to spec. Got it be a bad drive controller?

 

[crewchief888]

I took a look at the connectors. Tested for continuity and ohm they all tested good. Tested the main frame harness to the drive controller it tested good. The only time it happens is if you are going fast and you travel over excessive bumps and then it locks up and only forward right side won't move all the other functions for movement operate to spec. Got it be a bad drive controller?

unbolt the drive controller, flip it over and check for any cracks on the connector side.

i ran across a couple SJC machines with very intermittent and erratic faults.
i found the epoxy (?)that the controller is sealed with was cracked.

 

[Jacksondemo2754]

unbolt the drive controller, flip it over and check for any cracks on the connector side.

i ran across a couple SJC machines with very intermittent and erratic faults.
i found the epoxy (?)that the controller is sealed with was cracked.

Cracks like those?

 

[crewchief888]

yes
if you are absolutely positive all the wiring and connections are good, i'd replace the controller.

 

[bobcan]

Yeah, knowing what I do of Electronics and Circuit Boards, there is a very good chance that there are components 'pulling away from the sockets or soldered connections' because the Epoxy is adhering to the case cover and holding them in place until a physical shock opens the circuit once you hit a big enough bump.. then they quite likely connect somewhat again almost immediately, and with small voltages being used, it may go into fault quite easily .. That block of epoxy would add quite a bit of mass, unfortunately, and although trouble-free when sealed up the separation likely makes sense as the cause, if it shifts about during use, and also would be letting Moisture and Dirt in too, out of sight _ Good Luck there!!

 

[Jacksondemo2754]

Thanks guys I'm going to start there. I have a manual and a wiring schematic so I know the wires are good I followed them all the way to the drive controller