Mten4 stopped working after buyer took shipment?

[Brokenmten3]

I recently bought an mten4 and after testing it indoors decided to resell it to buy a different EUC. It was working perfectly prior to the sale. I sold the item and the buyer stated that it doesn't work - namely, that it doesn't self-balance and there is a red light on the controller when you turn it on and it also doesn't connect to the apps anymore. I never connected the wheel to any app since I only tested it for a few minutes.

The buyer stated the only way to shut it off is disconnecting the power cord. After receiving the item back, I can confirm this is the case. How likely is it that the mten4 would suddenly stop working like this? From my previous experiences with my mten3, it was quite resilient could take a lot of damage before bricking.

Also, any ideas how to make it work again? Looking at YouTube disassembly videos, the wheel looks pretty simple and low maintenance, so it was surprising to me this happened.

[alcatraz]

Sorry to hear it. A few questions.

Was it shipped with transport mode on or battery disconnected? 

What's the battery level now?

Are there any signs on the packaging that the wheel may have turned on by itself? (tire marks, dust)

Begode puts white goop on all cable connections. Check to see if it hasn't been broken. It can be hard to tell but it would indicate the buyer swapped parts or tampered with cables. I know this is very unlikely but might be worth a look. 

Check if the motor spins without resistance. 

Check if the motor cables are plugged in the right order.

[Brokenmten3]

-It was shipped to buyer in transport mode and returned with battery disconnected.

-Battery level does not show on the board.

-No.

-Doesn't look like any parts were swapped out.

-I can spin the tire manually. The wheel basically doesn't do anything by itself.

-Cables look okay.

 

Thanks!

[alcatraz]

Hmm. That's interesting.

Tried charging it? Check the charge port for bent pins. Does the charger's light switch colors when plugged in to the wheel?

If you've got a multimeter you can check the pack's charge level by measuring the voltage across the output (voltage mode VDC, carefully, don't let the probes touch).

You could also check the operation of the power switch with the multimeter in resistance mode. There should be 0ohm when pressed and infinite ohms released. 

Check the board for visible damage. I had a blown transistor on the pack of mine and the board looked new from the front. Obviously I'm not saying take it apart, but shine a bright light and look for discoloration from the angles available.

It's good to rule these things out before going further sending the wheel for repair.