Circuit Board Repair - Help

Hi,

my Black and Decker 20V DC Lithium Sweeper leaf blower stopped working and upon taking it apart I discovered burn marks on the circuit board. The marks were around what appears to be two solder dots as outlined in the photo’s I’ve attached.

Can anybody please help to identify this specific part and tell me, if possible, how to repair it? My electrical knowledge is limited but I’ll do my best to assist with any inquiries.

Sorry in advance for the quality of the pictures.

Any instructions or suggestions would be greatly appreciated.

Hello @cajoromi,

Unfortunately in a situation like this good pictures are often the key to identify the damaged component.

Are there any markings on the board that my symbolize the type of component?
Do the solder pads appear like they housed a part that is now missing?

-Robert

Hi Robert,

thanks for your reply. I posted the same thing on another forum and this seems to be the winning answer:

That looks like there was a resistor there; look around inside the casing for a part about that size.

Looking at how it’s wired, that a PWM driver section for the motor; the driver is the 8 pin chip, and the lower part would be a diode, near the red wire there.

That would likely be a current limit resistor/fuse, and it looks like it did its job, lol.

I would guess it would be a small value resistor, like 0.1 ohms or smaller.

I’d try a single strand of wire from a piece of multistranded appliance cord; one “thread” out of an 18awg zip cord cable is about 40awg, and that blows at about 20A .

If you can find the original part, there may be a number on it, but I doubt it.

Make sure the motor spins easily before you do this; the motor stalling is what cause this, either there was crap in there, or the bearings in the motor are bad.

Try it before you put it together, it’s easier to put out if it catches on fire. :)