DeWALT Vacuum DVC581H - How do I Repair Broken Battery Terminal?

Good day community,

I have an interesting question I hope. It is a re-opening of a previous thread that has been closed, but with a spin… so different:

I own a DeWALT DCV581H Corded/Cordless Wet/Dry Vacuum. To be specific, the battery port for cordless use stopped working, however the the vacuum still runs when it is plugged in.

So that’s the spin! I assume that that whereas the MOV and fuse needed to be replaced so that the vacuum would work when plugged in, as was discussed in the previous thread (above), MY PROBLEM is that the vaccum doesn’t work when I attache a 20v battery, so there must be other circuitry that is damaged… I am just unsure what…!?

(And yes, i know I can always call DeWALT, but it’s off warranty, and no service center wants to deal with this. Honestly, I just don’t want to throw out something that still works half as well…)

Any help would be super appreciated. and I am ready with my soldering kit to get this repaired!

Cheers folks

Have you tried disassembling the vacuum to look inside? If not, I would highly recommend doing so and looking for any visual signs of damage. Once inside, you should be able to locate any damaged components if you look carefully. The fuses are soldered down, so you will need to use a multimeter, etc… to test these for continuity. I believe all of the battery circuitry is on one half of the board (the side with the shorter heat sink). There may also be a fuse hidden in the colorful wires that connect the board to the battery terminals.

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Hi Kyle_Luiten,

Yes I did open the vacuum. It was the first thing I did, but for some reason yesterday I was unable to post any pictures…

Here is where the wires run from the battery terminal to the circuit board:

As you can see there is a red, black and blue. Nothing looks physically damaged but I guess I will need to buy the multi meter to test the components as you said. I’ll guess I’ll also have to do some YouTube research on how to use it. (That’s okay though, I think it’s a great skill to learn and it’s been on the bucket list for a dog’s age)

If you or anyone might know exactly what and how to test the components, I’m also open to shortcut version too :wink:

Did you find a fix for this? I have the same problem.

Just fixed mine. If you look just up from the blue wire you will see the board is discolored from an over temp component. If you flip the board over you’ll find an FDD8874 transistor with some black discoloration around it. What happened to mine is that the transistor failed and become a short but then overheated when it stopped limiting current and melted itself off the circuit board. I have no idea what the transistor does but replacing it allowed the vacuum to function again. The part can be ordered here: https://www.digikey.com/en/products/detail/on-semiconductor/FDD8874/3908103?utm_adgroup=Semiconductor%20Modules&utm_source=google&utm_medium=cpc&utm_campaign=Dynamic%20Search_RLSA_Buyers&utm_term=&utm_content=Semiconductor%20Modules&gclid=CjwKCAiAzNj9BRBDEiwAPsL0d-L9aya0_qYKo9SadmO94MlmGHKvfsjpfFmA3A9i23gFI40ItzUqfBoCrlQQAvD_BwE

Also, I blew the fuse in the brown wire while I was working on diagnosing the problem. This wasn’t the case initially because the AC was working but if it stops working then you will most likely need to replace this fuse.