Fix Blown A4988 Stepper Motor Driver


Pretty certain I've blown a couple in the past and just blown another now. The circuit was working, then after changing about (there are three A4988 on the board, I was testing with one A4988) it stopped working, however upon changing to another A4988 it started working again. Honestly I think I blame the capacitors in the PSU and me being too quick on the last change over... and spike (above 35v)

So... circuit is correct and the A4988 Stepper Motor Driver board is not working... Any further insight into what is wrong and if any chance of fixing...

...or any further protections I can take to prevent this (and I do have capacitors across each boards 12v input (usually I use 100uF, but here they are 47uF 35v Electrolytic))

After reading Pololu - Understanding Destructive LC Voltage Spikes should I try a resistor in series on the 12v input?

After looking at the datasheet:

and schematic diagram here:

Would identifying and replacing C1 / C2 (CIN1 / CIN2), fix the board?

This is probably just a thought experiment for me as I've never performed any SMD soldering (reflow), etc... Just mainly wondering if they are fixable if in a pinch?

Many thanks :smiley:

NEVER change any wiring with the power applied.

Most likely the chip itself is blown.

Not knowing your skill set. I would say do not expect it to work, those chips are hard to work with unless you have the tools. However it would be great experience. Since you change things fast, I do it to add something in the range of 27K across the power supply. When possible I also add a LED as an indicator.

lol, I'm sort of self taught over the last few years, I watch more than I experiment. I have a programming and drafting background. I even had to do a quick calculation to check if the 27K was a trick suggestion :blush:

I like the resistor idea... Thanks

More excuses, in my defence I was rushing for dinner, was the missus or magic smoke :wink:

I checked the value as I use a lot of 27K resistors but it is ok upto 36V. Using SMD 1206 parts they can be soldered between the leads of a radial lead cap. Go for the missus, you can always generate more smoke:-)

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