Dear all,

after lots of month today i wanted to play with my motorized unimog outdoor. I put 6x freshly charged eneloop batteries into it and wanted to get started. But after 1 meter of driving the engines slow down and stopped. It looked as if the batteries were empty. Okay, may be something was wrong with this set of eneloops. I change them to anoter fresh set... but the result: the same problem!

In december of 2014 i bought the unimog together with all the power functions. In february i stored the model (without batteries) in the cubboard. everything worked wonderfully.

Now today nothing is working anymore. I have tried three different sets of batteries, all with the same result. I measured a set of battieres, each cell has over 1.4 volts. The voltage breaks down immediately when starting engines.

I have different types of motors connected directly to the battery box. Small motors are running a little longer, the large L-motor stops after a few seconds. That's why I do not think that an engine is broken. But can the battery box go broke? Is there any way at all electronics in it other than a switch?

I am confused and my daughter is sad that the Unimog could not drive on the lawn today. I hope someone can give me a tip.

Are you sure the gears aren't stuck or something.

I may have an answer to your problem; I have multiple PF battery boxes and one of them exhibits the same problem that you have described. If you have a second battery box then I would suggest replacing the one in the MOG with it and seeing if it works.

Hope this helps,

John

Swap out your battery box. I had a bad one from my 9398 which caused the L motors to squeal and stall out

Unfortunately i have no other battery box at the moment for testing.

i think i will try to open the box and look for something wrong before i order a new one.

It´s strange that somesthing got broken into the cupboard over the month...

Call Lego, they will send you a new one probably for free. But then you have to return the old one so don't open it.

Unfortunately i have no other battery box at the moment for testing.

i think i will try to open the box and look for something wrong before i order a new one.

It´s strange that somesthing got broken into the cupboard over the month...

Open it and see if you can find the problem your self

i opened the box. There are the contact plates only and a small board with the green LED, the slide switch and a small SMD component that I can not identify. Thats it.

I will order a new box and hope you are right

Sariel also had a bad box in his 9398, so a new one should fix the problems!

i opened the box. There are the contact plates only and a small board with the green LED, the slide switch and a small SMD component that I can not identify. Thats it.

I will order a new box and hope you are right

That is the PTC resettable thermal fuse.

That is the PTC resettable thermal fuse.

Which might actually be the faulty part!

Big thanks to all of you.

Yesterday the new box arrived. I placed the same (!) batteries from the old one in the new box and - wow - it works fine.

Big thanks to all of you.

Yesterday the new box arrived. I placed the same (!) batteries from the old one in the new box and - wow - it works fine.

Glad to be of assitance. Replacing the battery box was the only solution to the problem, that came to mind, since all of the motors were effected at the same time.