Sunday, 9 October 2016

Wizboard hoverboard segwway scooter gyro board repair.

Component transfer service: 

I thought I would offer a service to transfer gyro board parts over as I still can't see any Wizboard configured Gyro boards for sale. If you have faulty gyro boards and want your replacements modifying to fit your wizboard, leave a comment below with your email and I will get back to you !

I was passed a Wizboard branded balance board for repair, the first one I had seen.

A quick look on the web showed how it should work, no front lights should come on until you stand on the pressure pad. This one was powering on with both lights immediately on. The motors would not energise at all.

Again the web showed this was a fairly common failure, the solution being to replace the gyro board for each affected side.

I found this a little strange as I would not have expected both to fail at the same time ? and also wondered about the failure mechanism, especially as it is common fault ?

Nothing was showing up about 'repairing' the board, just swapping them out.

I didn't want to spend too much time as the person wanted the board back working ASAP and there was a quick solution but I thought I would at least have a bit of a look into it.

As a quick first check I checked the pressure pad switches were working correctly, they were.(no voltage across the connector, press the switch and it had about 3v across it).

The board doesn't have a great deal on it, a 3 axis chip, a microcontroller, a fet and voltage regulator, some passives.

All the passives, fet and regulator checked out so my money was on the 3 axis chip, the micro second but as there was no way to flash a new one I just went with the 3 axis chip.

I ordered 2 new chips and swapped them out, chips were removed using hot air and flux, and replaced the same way, touching in with the iron afterwards as I didn't want to overheat the chip. What is going on inside a 3 axis chip to sense movement ! its like magic, I will have to read up on it.

Sadly no success, board behaved exactly as before, disappointment.

So two new boards were sourced off ebay, cheapest price was £32 for two delivered.

There were no identical boards, the Wizboard does not have opto sensors mounted on the board, the switches are mounted in the pad and connect via wires, however the layout and components on the ebay boards looked almost identical except for this so I ordered some with a view to swapping parts over.

The boards came and a close inspection revealed a few of the resistors (for LED current limiting) were a different value.

Also although the connectors on the board looked the same the Wizboard wiring would not plug into them as the molding was different.

So as well as swapping the sensor connectors over, I swapped all the other connectors and the SMD resistors for the LED's.

Put it all back together ( had to open up the holes on the new PCB as they were about 0.5mm out of alignment).

Success ! it was nice to see the board back up and running, I had a quick go before handing it back !

I would have liked to have had a proper go at diagnosing and fixing the original boards, but if as I suspect it was the micro, it would have been more work to source the code and flash it (if available at all).

If you have had success actually repairing the boards or why they fail I would be very interested to know !

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