Asked — Edited

Defective Ez-B V4 Controller?

I got my Ez Robot developers Kit for making my Wall E robot. I got all the servos up in place and tried to power on the controller. I am using the Li-Po battery that is available on the the store. I connected it to the plug that goes into the controller but I couldn't get the blue lights for the controller to come on nor did the controller make any sound. I haven't used it before and this is straight out of the box. I was wondering how I can diagnose if it is a faulty part or I am doing something wrong.


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do you have a multimeter or voltmeter?

If so, measure the voltage from one of the digital power pins on the board to a ground pin on the board. Do you get anything?

Measure the voltage of the battery. What does it read? Is the battery buldging on the side?

Is the + going to the red side of the battery and the - going to the black side of the battery?

Does anything happen when you first plug the battery in? Was there a pop or anything?


The red wire is going to the plus sign and the black wire is going to the negative sign.

The battery is not puffed on any side.

Nothing happens when I plug the battery in.

I'll update you in the evening with the multimeter readings.


did you check the fuse?


As @nomad said... check the 20amp fuse in the base.... you'll need a Philips screwdriver....



is it not the best after replacing the fuse to test the ezbv4 on its own whithout servo conneted.i bin told there's always a reason why the fuse blew up.


I am trying to walk him through a series of steps that will help him to determine the issue. It could be the fuse or the poly fuse or many other issues. It could be that the barrel jack isn't the correct polarity. It could be a defective V4. If he is getting power to the plugs that I asked him to check, and it is the same as the battery voltage, then the rest of the things don't matter and it is a defective V4.

Going forward, this is how I am going to be answering questions. It will take longer but will help others more who read the posts.


We get a lot of people hooking it up backward who are new to electronics. This might have been the case - if the tutorial was not followed. When the ezbs are returned to us, we can see what happened :)

Let's hope his was a fuse - best way to tell is with a multi meter. Anyone getting into electronics better have a multi meter :D


I second the suggestion about buying a multi meter and learning how to use it. I don't know how anyone can be in this hobby without one. I would be truly lost without mine. Not only is the lowly multi meter critical to have in any type of electronic work but they are so useful in day to day handy work and troubleshooting around the house and garage. Electricity is everywhere and not to hard to learn, understand and manage. Without simple skills like using a basic multi meter you may as well just let someone else do all the fun stuff. :)