Jig saw flashed out

[AJB Temple]

Is this a bin it job?

Milwaukee mains 240v jig saw. About 4 years old but very little use and in pristine condition.

Was using it to cut pipe slots on a bench yesterday in 25mm oak floorboards. Had been fine. Not much dust. Suddenly the saw goes bang and there is a flash out of the back and some light black soot marks around the rear red plastic vents.

Saw was not stressed, cable was not caught, sharp blade.

Is this a case of bin it or strip it down and try to repair. I have a pro Bosch as well so not desperate.

 

[worn thumbs]

I would definitely take ten minutes or so to have a look inside before binning it.If you are lucky it might just be an accumulation of damp dust in there.Have you looked at the fuse?I fear that if the saw has a soft start there may not be much hope as they tend to use something a bit more sophisticated than a plain switch.

 

[Distinterior]

My Millwaukee jigsaw did exactly the same thing about 18 months ago. Mine is a bit older than yours and had done a lot of work, but I was right in the middle of a job that needed the use of the jigsaw. I went and bought a Festool cordless version to replace the Millwaukee and get the job finished......I've yet to strip the Millwaukee down and see if I can find what went wrong with it. It may just be the brushes....? I did change the fuse, but that didn't fix it.

 

[MikeG.]

Nah, you've let the magic smoke out. It can't possibly work now.

 

[sunnybob]

Theres a very good chance its just a knackered mains cable.

 

[AJB Temple]

Thanks. I think I will strip it down. There is a tool repair place not that far from me in Maidenhead, and they charge £15 to inspect and diagnose, with a no-obligation repair estimate. I have three tools languishing in need of repair so I might give them a go.

 

[sunnybob]

Just unscrew the panel where the mains lead goes in. If its the lead you will see the scorch marks. less than a fiver to replace. If it isnt obvious, then take in it.

 

[AJB Temple]

Thanks. Will do.

 

[beech1948]

Sounds like a capacitor gave up and flashed out. Happened to me on two tools. Took it to my local tool repair shop and it cost me £15 to get it fixed.

 

[AJB Temple]

It being Christmas, I took the casing off. No dust inside the machine. No evidence of mains cable burn and the live tester showed current through the cable. Brushes are almost unworn. although there was a big flash when it happened, there is very little blackening inside the case.

I think I may as well take it in for repair.

 

[sunnybob]

HAVE YOU CHECKED INSIDE THE PLUG?
Sorry, caps lock got away from me (hammer) (hammer) (hammer)

 

[AJB Temple]

No Bob. Embarrassed. Because fuse was not blown (since live was reaching the tool) so It didn't occur to me. But I will now.

 

[sunnybob]

If youre using one of those pens (really dont like them), its quite possible you you might just have live in but no return circuit. A loose or broken neutral wire will cause a big flash.

 

[Zeddedhed]

Suddenly the saw goes bang and there is a flash out of the back and some light black soot marks around the rear red plastic vents.

Light black?

Grey, perchance?

 

[AJB Temple]

Yes. Light black is a sooty version of grey.

Live in, Bob, means fuse is not blown. Therefore problem resides in the tool somewhere. Tool is now at repairers.

 

[sunnybob]

Live in means the fuse is not blown. #-o
it does NOT mean you have a circuit back to the supply. (hammer)
A loose or disconnected neutral in the plug will stop the machine from working.
If all you have to test a circuit with is a light pen, then use it to see if there is live at the neutral terminal of the motor. That will tell you if the motor windings are complete, thereby pointing an arrow at the return wire.

 

[AJB Temple]

Thanks Bob. I did check the plug, as you advised. The fuse is OK, the plug connections all OK. Cable appears undamaged. Pen shows that live feed makes it into the tool, but there is no return. It's easy enough to get the case off the back of the tool, as it's clearly intended to be easy for a brush change. Brushes had hardly any wear.

I do have a multi tester, but I am no electronics expert and stopping the tool down further looked like it would be hard to get back together again. So I carted this Milwaukee jigsaw along with a Swiss made Bosch pro jigsaw and a Milwaukee impact driver off to the repair shop and I will see what they say. I will report back when I get the tools back. The local tool guy charges £12.50 to strip a tool down and diagnose. Then I pay for whatever else is needed.

 

[DTR]

Pen shows that live feed makes it into the tool, but there is no return.

Not sure what you mean by a pen, but unless it references back to Live, it will not tell you if the neutral (return) is present*.

*Well, actually it will show everything as live up to the first open-circuit, wherever that may be.

 

[sunnybob]

Sensible move. I spent most of my life repairing machinery, i cannot count the number of times I found a simple loose wire (after travelling a 100 miles #-o (hammer) )
My personal best (?) was to spend an entire day travelling to and from a supermarket whose manager point blank refused to fault find over the telephone, only to find on arrival that cleaners had unplugged the chicken rotisserie oven to clean underneath. It was small consolation I stuck him with a days wages when he could have been up and running in 10 minutes and for free :evil: :evil:
checking costs nothing, you may be lucky next time 8) 8)

 

[Phil Pascoe]

Some years ago I told a friend who earned his living repairing small electrical and white goods that at work when a chambermaid or cleaner came in with a non working vacuum I always checked the lead for continuity before sending them for repair - and that nine times out of ten there was a break in the lead (usually an inch or two from the cable grip) or a wire yanked out of the plug. Yes, he said, nine out of ten vacuums that I get are the same.