Need help with fried focbox

When I connect my focbox 1.6 to Vesc tool 6, i firstly went to update the firmware from 5.02 to 6.00 and then I went to setup an old hub motor (picture 1) which originally had a 5 pin hall sensor cable (picture 2) which I converted to a 6 pin cable (picture 3). I plugged it into the Vesc and When I got to the page where you have to select the motor poles I paused the procedure for approximately 5 min to look up the number of poles, but when I put the correct number in and went to start detection I noticed that the Vesc disconnected itself. When I check the Vesc I noticed that was no longer any light anywhere on the controller, so opened it up and I noticed that as soon as I would connect it to power, the diode (picture 4) gets extremely hot within seconds. I also compared it to the other working focbox I have and noticed that on the broken one the left side of the diode is shorted to ground (picture 5), but not on the working one.

Picture 1:

Picture 2:

Picture 3:

Picture 4:

Picture 5:

Full top side view:

Full bottom side view:

(the cables are there, because though that I just had to reupload the firmware at first)

This is way out of my reach concerning electronics, so help would really be appreciated. Thanks

Does anyone know the specifications of that diode so I can order a replacement?

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There was a guy @JohnnyMeduse in the US and @MartinSp in Slovakia who used to repair VESCs some time ago, not sure if they are in the biz any longer.

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Maybe @jaykup

This should be the original part number for that diode



Thank you!

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Can i also replace the drv8302 with a drv8302DCA, because there are no drv8302 in stock anywhere.

Yeah, same thing.

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Thank you very much! I hope replacing these will fix my problem

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Is there a possibility that the processor is also damaged? I am not quite sure if I should replace it too.

Test resistance between 3.3v and ground on the swd port. If it’s less than ~2 ohms probably the stm32, but the canbus chips on these can also short the 3.3v rail. If it tests fine (high kohms) then processor is probably good.

Can also check phase to phase resistance to see if they are all about 60-80?kohms. Looking for consistency to see if any mosfets are shorted.

Note that you’ll need an stlink v2 to manually load the firmware if you do have to replace the stm32. It won’t load via USB the first time.

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I usually do it with a Makerx hi100 over the swd programmer

I just replaced both the diode and drv chip and the same thing as in the beginning is happening when I connect the Vesc to a battery.

Welcome to VESC repairs… they are almost never straight forward haha

Since you have a working Focbox, I’d start poking around with the multimeter to compare the two and see what’s different. Make sure the new diode test correctly, etc.

You might have a shorted ceramic cap that is the issue but it’s presenting in the diode. A thermal camera can really help here, but you can also test these with a multimeter.

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