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VESC C39 blew up

Hello everyone,

recently, the C39 capacitor on my VESC blew up. I took a short ride on my board, had to cross the street and picked up the board. On the other side, the board did not accelerate. So i connected the VESC to BLDC tool and it did not show any fault code. It even says there is current in motor when triggering the throttle on the remote but the motor will not spin. When i power the VESC it does not blink three times on start up. Later i recognized that C39 blew up. I contacted the supplyer (Enertion) but the do not respond since 4 days or so.

So my question: What is the C39 for and can i repair the VESC on my own or should i try to send it back to Enertion if they eventually will respond? Also, do I have any warranty on the VESC? I purchased it roughly 1 month ago and wrote the board for an overall of maybe 5-6 hours. Moreover, the capacitor must been blown up when there was nearly no load on the board/VESC what seems to me like it was not my fault and even something like a production failure.

Enertion has no warranty unless you buy it separately.
You should be able to repair it if you have soldering iron and some SMD soldering skills.
It’s 10uF 50V cap, SMD1206 package, order code: 963-UMK316BBJ106ML-T

I do have a soldering iron. But are you sure it can be repaired like this? To me it seems like there is no connection to be soldered to on the burned side. or can i just add a good ammount of tin on that side?

I found this, do you think this is compatible?

And how could this actually happen when the board imho was not under load?

If the trace is burnt and lifted, you can, with a lot of care, scrape a bit off the protective coating and bridge to it.

I scraped a bit off and got some conducting material beneath it. Between GND and this the resistance i measure increases over time to over 20k. Hopefully this is the right connection.

But i still do not know how this could happen when the board was not under load…

That cap is for input cleaning. Most likely it was blown by a spike as you plugged it in.

Here you can see its position:

But should the VESC not function normally even without that capacitor?

In theory it should still power up and every thing

Pretty sure that Enertion has several months of standard warranty on their electronics?

No. On VESCs, they don’t, unless you buy it.
They have warranty on Raptor for example.

How many volts is your battery pack ??

It is about 25V, 6s.
I am waiting now for the capacitor to arrive. But I am sceptical if this will make the VESC boot and function normally again (did not blink three times at startup) since the blown up capacitor only was for stabilizing the supply voltage of the drv.

Well, shorted caps usually just start conducting as a normal wire would, so if that’s the case then you would have a short to GND.

So now I soldered the capacitor to the VESC but still no change. On startup it does not blink three times, but led 1 and 3 are always on. Bldc says there would be current in motor but the motor will not spin. Motor detection gives a failure. But no drv fault code (NONE)…

If this might be helpful, here is a picture with the soldered capacitor:

Is that solder bridged to the pins on the DRV chip? or what is that white thing over the first 2 pins closest to the cap?

I knew this question comes up :smiley:
But don’t worry, it’s just some hotglue to isolate the drv from tin coming close to the contacts of the drv. The (faulty) behaviour of the vesc did not change at all…

I would start by crossing things of the list.
Check the 5v rail, check resistors, caps, etc.

I am not shure what the 5v rail is. If it is the round component right next to the drv, it is 5v.
Unfortunately i do not have a multimeter that can measure the caps…

5v rail is any part of the board that is supposed to have 5v running through it, you can test the +5v pin on the canbus or uart port. For the caps, you can at least test if they’re shorted.

Everything seems to be normal, i could measure the 5v at several different spots. Resistors seem to be ok, too.