Asked — Edited

Suddenly Can'T Power Up

Started playing with my new EZ-B v4 from the Developers Kit yesterday and all was going well till I got the low battery warning and replaced the batteries (6 AA rechargeable), only to be unable to power up anymore. No lights, no sound, no connection. Very disappointing.:(

I used a multimeter and there is 7.2V coming from the battery pack and 7.2V out the power shell. There is also 3.3V on the controller board where the pins contact. There is a soft disrupted buzzing sound coming from the controller, but only when I push down on it, which leads me to believe power is circulating somewhere, but there may be a faulty connection.

I'd appreciate technical assistance and help with returning the part if needed. This wasn't a cheap kit for me so I hope to get back up and running again soon...Thanks!


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Sounds like you should check the fuse perhaps?

Open the shell and carefully inspect for damage or solder bridges(solder points connecting)


If 3.3V is present the fuse should be intact.

@Jess where are you measuring the 3.3V, at the ADC pins?

No lights and sound is indicative of no power getting to the ez-b, are you certain that you have 3.3V working?


Thanks for the help. I will take a photo of where I measured the 3.3V when I get home. What would the buzz I hear be coming from if there is no power?


If the 3.3V switching power supply had an issue it could possibly create a buzz, but if 3.3V is working then it would likely be the speaker.


Here's where I got the 3.3 V. Was I supposed to measure somewhere else?

User-inserted image


Yes - that means your batteries are dead. That point where you measured is the VIN, which is the voltage in. If you are using the 6 x AA battery holder included with the dev kit means you should have at least 7 volts. If you are only getting 3 volts, this means the batteries are dead.

Replace the batteries with new ones. Have fun!

PS, be very very very careful measuring voltage at the position. If you accidentally short the GND or VIN to any of the components around, it will blow the EZ-B. You cannot short pins together of electrical components. Be very careful. In the photo, the pins are very close to shorting between the VIN/GND and components around.

To understand more about the EZ-B v4, there is a fantastic tutorial that also includes a datasheet. Here is the direct link:

The datasheet will outline what the pins are and which ones carry voltage. You do not need to take the EZ-B v4 apart to measure the voltage. The voltage can be measured at the pins, which are exposed on the top - these are the same pins where you connect the servos and sensors to.

The datasheet (from the link above) will explains the pins and expected voltages. For example, the ADC pins are 3.3v and the digital pins are VIN. VIN means the voltage input to the ez-b.


Wow, yeah replaced the batteries and that was it. I could've sworn I measured 7.2V coming from the battery pack and 7.2V out the power shell though? Hrm, well, now I feel slightly dumb but I least my EZ-B works again. blush Will try playing with it a bit more before deeming the issue resolved. It still seems a bit sketchy to me.

And I will be careful about the pins...Thanks everyone!


We are happy you are back up and running. Have fun!

Ron R