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Terex TB42

telwood

Well-Known Member
Joined
Mar 20, 2013
Messages
123
Location
GA
I own a Terex TB42 boom lift. Gas motor etc. Everything works great but last week I lost forward drive and the high speed function. I've read the other post and realize these things can be a pain.

So I bought it from a dealer and called them to do a site service call a couple weeks ago. Called them back the other day and they pretty much whined saying their Optimizer 4 must not be working because the motor shut down every time they hooked it up. It seems like they would still be able to troubleshoot based on just not going in forward and the high speed toggle. The tech said he thinks it is wiring because the drive motors rarely go bad....who knows but I got no answers that have fixed it.

I played with it some today just checking connections and it seems to only drive backwards no matter which direction I move the joystick. The high/low toggle does nothing as it just stays in low speed.

Logically it seems the speed toggle must be bad and maybe the joystick? But reading about all these OEM Controls I am a bit lost what to do next. I plan to call them Monday and others and start trying to figure this out but hoped someone could enlighten me with the possible troubleshooting? All controls except those 2 work perfect.....it can't be moved from the bottom controls so I am referring to the basket controls. Wheels steer fine and all boom actions are good.

Any opinions would be appreciated,
Tom
 

barklee

Senior Member
Joined
Aug 4, 2009
Messages
903
Location
ohio
Does that have the superflex circuit board in the lower control panel? We have had a few go bad and they will do some crazy and scary stuff. I would check that out.
 

telwood

Well-Known Member
Joined
Mar 20, 2013
Messages
123
Location
GA
Yes, I am working with OEM to diagnose the Superflex board. Apparently they can be sent in for rebuild but am trying some other things first that may be the culprit
 

barklee

Senior Member
Joined
Aug 4, 2009
Messages
903
Location
ohio
I noticed if you press your finger on the board while using the function that doesn't work it will start working if the board is bad. Try that out.
 

telwood

Well-Known Member
Joined
Mar 20, 2013
Messages
123
Location
GA
Just to follow up for anyone with this equipment. I chose to call a dealer and that was a waste of time as they sent a tech and fixed nothing. I did the research and figured out how this thing works. More time that I'll admit to but probably the best way owning older equipment.

The forward and reverse was fairly easy to diagnose as it has a device called a digi-sensor attached to the base of the steering/forward reverse control joystick. An LED light comes in both forward and reverse setting if it is working properly.

In my case the LED for forward wasn't lighting on my unit so the digi-sensor is bad and needed replacing.

A great source for electronic parts is Hindley Electronics. They seem to have parts for Terex, Genie, Skyjack.
 

telwood

Well-Known Member
Joined
Mar 20, 2013
Messages
123
Location
GA
Changed out the digi-sensor and machine run great in forward and reverse. $169 part and about half an hour labor.
 
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