DeWalt multi-tool issue

[kjacko]

Hi all,
my out of warranty DCS355 18v multi tool keeps cutting out on me.
I’ve changed blades and batteries and it’s not either of those.
So even if cutting into plasterboard if I go full speed straightaway it almost always cuts out (it should not and has never done that before). So I have to gradually increase speed, even then it might still cut out on me.
Took ages to chase out a channel in plaster yesterday.
I’ve been using multi tools for years, my method of operation hasn’t changed so it’s not me using it wrong.

I can get a new naked tool for £99. I’m a DIYer so don’t use it daily for work, but I want it to work properly when I do need to use it, which is often enough.

Any ideas?
Cheers

 

[blup]

A loose connection that cuts out under vibration.

If you can’t fix, it get the corded Makita, three year warranty.

Blup

 

[big-all]

what size off battery and how old??
and how much charge in the battery ??

 

[kjacko]

what size off battery and how old??
and how much charge in the battery ??

Thanks, but I did mention that battery wasn't the issue (because i'd tested 3 different ones all with full charge that work perfectly with my other tools).

A loose connection that cuts out under vibration.

If you can’t fix, it get the corded Makita, three year warranty.

Blup

Lol, i had no issues until my little brother borrowed it
Regarding your vibration theory: interesting, but if i sneak up on the speed it seems to work ok (for a while). Its brushless so certainly can't be a brush issue
I'm not going back to corded. I did have a 3 year warranty but its expired now.

 

[big-all]

i have the same one and never had a problem so afraid if its not the batteries i aint no use here

 

[kjacko]

i have the same one and never had a problem so afraid if its not the batteries i aint no use here

lol thanks bud. The irony is after trashing mine (well I think he did) my brother went and bought his own!
Might just have to buy another one and let my mate take the dodgy one apart. He loves doing that to DeWalt tools for some reason.

 

[big-all]

when you do get the new one try running the side by side one after the other and see if you can detect any differences in sound/speed/vibration /speed build up' slow down
just anything to give clues ??

 

[Deleted member 174758]

I had a Fein (corded) that did the same sort of thing. A wire had broken inside where it was crimped into a bootlace ferrule so I suspect you may have a broken wire somewhere. After all these tools vibrate a heck of a lot. I couldn't source a replacement ferrule which was small enough, so I just replaced he tool in the end as the original was nearly 5 years old (my cut off point)

 

[kjacko]

I had a Fein (corded) that did the same sort of thing. A wire had broken inside where it was crimped into a bootlace ferrule so I suspect you may have a broken wire somewhere. After all these tools vibrate a heck of a lot. I couldn't source a replacement ferrule which was small enough, so I just replaced he tool in the end

I've just found a video on youtube that seems to indicate the same issue i'm having and having just spoken to a local dealt repair centre they pretty much said similar to the video (without me even mentioning it). So it'll cost me £25 for them to repair, or nothig if they can't. In which case i'll need to buy a new tool.
Reckon i'll have a go at it myself first. I know how to micro solder.

 

[blup]

Thanks, but I did mention that battery wasn't the issue (because i'd tested 3 different ones all with full charge that work perfectly with my other tools).

Lol, i had no issues until my little brother borrowed it
Regarding your vibration theory: interesting, but if i sneak up on the speed it seems to work ok (for a while). Its brushless so certainly can't be a brush issue
I'm not going back to corded. I did have a 3 year warranty but its expired now.

If you are comfortable taking it apart you might find a loose connection. Otherwise time for a new one.

Blup

 

[opps]

A loose connection that cuts out under vibration.

If you can’t fix, it get the corded Makita, three year warranty.

Blup

Not disagreeing with you... but... why would the connection disconnect, and then reconnect? I guess that if, as per Jobandknock's post, if some of the strands have snapped then perhaps that might explain things.

For the record, I have only ever used a cordless multitool once (Ryobi). It was relatively new, and the batteries were relatively new. I was trying to cut through moisture resistant chipboard. It kept cutting out. In the end I used my corded Fein, which was fine.

I am wondering if something on the speed control PCB might be dodgy. Or perhaps the batteries are no longer to provide sufficient amperage.

 

[blup]

Not disagreeing with you... but... why would the connection disconnect, and then reconnect? I guess that if, as per Jobandknock's post, if some of the strands have snapped then perhaps that might explain things.

For the record, I have only ever used a cordless multitool once (Ryobi). It was relatively new, and the batteries were relatively new. I was trying to cut through moisture resistant chipboard. It kept cutting out. In the end I used my corded Fein, which was fine.

I am wondering if something on the speed control PCB might be dodgy. Or perhaps the batteries are no longer to provide sufficient amperage.

Who knows....

This is an interesting video, it suggests soldering can cause the wires connecting the battery pack to the tool to break under vibration, initially they are held in place by surrounding insulation but eventually fail. These small wires should be welded not soldered, the uploader suggests. Always difficult to tell with youtube, but it makes sense

Fix your Dewalt 20V MAX Li tools!! Easy fix for intermittent problem. - YouTube

Blup

 

[Deleted member 174758]

The Fein ones are crimped to the bootlace ferrules

 

[Mike13]

A proper ratcheting crimp tool does give a cold weld inside, The insulation then acts as a strain relief.

 

[kjacko]

Update on this, in case anyone else has the same issue…..
I took it apart, blasted it with a compressed air can to remove excess dust and gunk, sprayed it to hell with WD-40 contact cleaner, let it dry for 24 hours, put it back together, and……?
It’s like new, works perfectly
Thanks for all your input folks.
Case closed.