Created Buying a used hoverboard (markdown)

Buying-a-used-hoverboard.md

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+## What to check before buying a used Hoverboard
+### Compatibility with the firmware
+It's very hard to know if an hoverboard has a controller supported by this firmware, there are too many brands/models.<br>
+Usually the older models have single/mainboards.<br>
+You can ask the seller to open the hoverboard and send you a pictures, but he will most probably accept only if the hoverboard is defective.<br>
+Ask him what's the chip model/brand to verify if it's [compatible](https://github.com/EFeru/hoverboard-firmware-hack-FOC/wiki/Firmware-Compatibility#mainboard) with this firmware.
+
+### The hoverboard turns ON
+Press the sensors on one side, tilt the hoverboard in each direction to check if the motors runs smoothly.<br>
+If it's not working, the sideboard is probably defective.<br>
+If the hoverboard turns OFF, the battery has probably lost too much capacity and is not able to deliver enough current.<br>
+
+### The hoverboard doesn't turn ON
+Most of the time the battery is defective.<br>
+If the charger is still available, try to turn the hoverboard on while it's plugged, this will prove the controller is still working.<br>
+
+### Motors
+Make the wheels spin manually:
+* if you feel wheels are cogging, 2 mosfets of the same phase are probably shorted, you will have to replace it. The gate drivers could also be damaged
+* if the wheels are not spinning at all, it was exposed to water/humidity, you can through it away 
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