Cordless Dremel 8220 rotary tool power fault

[spleenharvester]

Hi all

I bought this Dremel several years ago (8220 + 880 2.0Ah battery). After about a dozen light uses it developed a power fault. I asked Toolstation to start a warranty claim for me and they just refunded me in full without asking for it back instead. Would be nice to fix it instead of consigning to the dustbin.

It is complete luck of the drawer whether it powers on or not. Sometimes it will be completely dead, no lights no response. Switching power on and off repeatedly and/or removing and reinserting the battery will eventually make it spring to life. After that it continues working perfectly until it is switched off again. Then once again it is luck whether it turns back on or not. This does not seem to be related to the battery charge level.

I am guessing it is a fault on the PCB, which appears to be p/n 2610021281, but there are no UK sources available for it and I doubt there will be in the future as it's been superseded by the 8240 series. Anyone encountered this before?

Thanks

[spleenharvester]

PCB pics

[stj]

resolder the big mosfets and wipe the speed variable with contact cleaner - see if that helps

[spleenharvester]

Cheers will give that a go. Sod's law it's working perfectly fine now that I've got it on the bench. Will update

[spleenharvester]

Found the fault, it was a fractured trace adjacent to the positive wire to the motor. Very very subtle, I only noticed it with a magnifying glass. Unfortunately I made such a mess of the board in the process of doing this that I really can't be bothered to fix it, so I think I am going to sell the parts and treat myself to a Milwaukee instead. :-)

On the pic attached it's the blue circle, the two sides of the trace were tinned before this photo was taken

[sam_sam_sam]

You could probably fix it if you remove all the solder from the traces where the wires going to the board and shorten the wire leads a little bit and just clean it up a little bit unless you really damaged the board traces then this is a different story but depending on how bad it is you used solid wire and even fix the broken traces

It looks bad but it might not be that bad if you wanted to spend a little bit more time on it

[spleenharvester]

It probably is fixable by a pro, not by a guy with a tremor haha. I managed to find a brand new replacement mainboard for £40 so I'm just going to go for that instead.

[spleenharvester]

Update, replaced the PCB, it worked perfectly for about a dozen uses now it's doing it again. Think I am just going to treat myself to the Milwaukee rotary tool instead.

[sam_sam_sam]

Update, replaced the PCB, it worked perfectly for about a dozen uses now it's doing it again. Think I am just going to treat myself to the Milwaukee rotary tool instead.

Be aware that sometimes the m12 battery packs have issues with charging them after they have some age on them and depending on where the battery cells are manufactured Canada made battery cells are used in a lot of them seem to have this issue