90xt boom/arm control locked

[jjohn21ca]

hi, Machine was running fine for a few hours when the boom stopped working. The up and down boom control seems to be locked. The stick doesn't move left or right but the forward and backward movement controls work perfectly. Any idea what this might be? I topped up the hydraulic fluid and all other functions work fine. I am assuming a safety lock has triggered or soemthing. thanks, john

 

[jjohn21ca]

A friend told me that there is a safety switch that when activated stops the controls from moving and that most likely the switch has stuck in the on position. Does this sound right?

 

[Tazza]

A friend told me that there is a safety switch that when activated stops the controls from moving and that most likely the switch has stuck in the on position. Does this sound right?

It could be a safety switch or even a bad coil that locks the hydraulics out. I don't know your machine, but there should be a coil on the control block that locks this function out if the controller detects the seat bar is not down or someone is not in the seat. This is just for safety. As the seats rot out, the sensor doesn't work so well.
I'd start looking at those 2 areas first.

 

[jjohn21ca]

It could be a safety switch or even a bad coil that locks the hydraulics out. I don't know your machine, but there should be a coil on the control block that locks this function out if the controller detects the seat bar is not down or someone is not in the seat. This is just for safety. As the seats rot out, the sensor doesn't work so well.
I'd start looking at those 2 areas first.

thanks, I think the sensors are ok because the safety switch indicator lights all work fine.

 

[Tazza]

thanks, I think the sensors are ok because the safety switch indicator lights all work fine.

If the lights lite up, i'd look at the solenoid.

 

[ben@g2g]

If the lights lite up, i'd look at the solenoid.

Is it just the up and down that is locked? Does the bucket tilt work? I'm not familiar with the 90xt, but I'd assume it's similar to our 40xt. There are 2 things it could be. Both are a pain because it involves lifting the cab, which also requires to have the bucket fully raised. 1 - there is an electronic switch, and a mechanical one that are activated when you lower the safety bar. In your case it might be the mechanical one. You will see a linkage behind the seat that plunges down when you lower the bar. This unlocks the control sticks. 2- or it could be the bucket lift solenoid. On our 40xt this was under your right elbow if you are sitting in the machine. You will need to tilt cab to access.