Dremel 4000 won't charge - battery or charger?

Hey all, I've got a Dremel 4000 that's been working fine for a year, but now it won't charge. Plug it in, the light on the charger doesn't even come on. I've tried a different outlet, no luck. Is the battery dead or is the charger toast? Any way to test? Thanks!

Have you checked the charger's fuse? Some of those have a little fuse inside. Also, try wiggling the connection where the battery meets the tool—sometimes contacts get dirty. Clean 'em with a pencil eraser. If that doesn't work, it's likely the charger. Mine did the same, had to replace it.

I had a similar issue with a different brand. Turned out the battery was completely dead, and the charger wouldn't recognize it. I used a multimeter to check voltage on the battery terminals. If it's below a certain threshold, the charger won't start. You might need to 'jump start' it with a charger in parallel. But careful, if it's a lithium battery, don't mess with it unless you know what you're doing. Otherwise, just buy a new battery.

I've seen it both ways. If the charger light doesn't come on at all, that points to the charger being dead. But before you buy a new one, check the battery contacts for corrosion or gunk. Sometimes it's a bad connection. Also, if you have a multimeter, test the charger output—should be around the voltage printed on it. If you're not getting that, it's the charger.