I think I killed one of myRobclaws

[dave]

It stopped working (not showing up as USB but LED's still lit) and then a few minutes later the LED's also failed and I could smell burning.

On removing the board there appears to be two scorch marks on the underside. I've circled the marks and where they lined up on the back of the board. Can you tell me what would cause components in those areas to fail please. I had set quite low limits on the amount of amps I was delivering to the motors (10A) and was running it off two 12v batteries in parallel, the voltage reading from them right now is 12.6. It was running just fine for about 10 minutes then failed.

I have a spare board, but they are not cheap and I don't want to swap it in until i understand the cause of the failure.

[Basicmicro Support]

The small chip is the 3.3v regulator and the big chip is a mosfet driver. The area damaged on the mosfet driver is related to the charge pump that generates the gate voltage for the mosfets. I dont see any direct connection between either other than the 5v switching regulator. If it was damaged/failed and allow 12+v through to each chip its possible that could explain the damage though I would expect the other mosfet driver to fail as well in that case.

Double check your wiring on the pin headers. Make sure you didnt accidentally short the 5v rail(check for shorts on everything of course). I dont see any way this could have been related to the current or main battery voltage(not directly) so you should be safe running the second board.

Please send this board in and we will diagnose the problem and repair the board. We can give you more speciifc answers on what failed when we do that.

[dave]

Thanks, I'll send it in this week. I did have it running fine for several days before the day it failed (where it ran for 10 minutes) but this was the first time it was under any sort of real load. It is used in a life-sized starwars BB-8 and directly drives the body via a 60RPM motor. I'll check every wire tonight for shorts and swap out with a new board. Thanks.

[Basicmicro Support]

You might want to send me the motor model numbers/specs as well. Fromt he picture it looks liek you have a 2x15 or a 2x30. Please confirm which of those as well.

Also the base you are mounting the board too look slike wood?

Thanks.

[dave]

Sorry for the delay, shipping tomorrow.

The base is 3D printed.
The model is 2x15
The motors used are: https://www.servocity.com/html/60_rpm_h ... 2jdD7grJaQ

In software I set the limit to 10A to be safe

[Basicmicro Support]

Where you using the encoders on those motors at the time it failed?

[dave]

I had them hooked up for both M1 and M2, but only using them on M2. M1 was PWM, M2 was position controlled.

[Basicmicro Support]

It might be related. PID control usually puts more stress on the motor controller than PWM and the one channel that has visible damage is channel 2 but I wont know more till I can look at the board.

Did you get a chance to send it in yet?