How Do I Repair an Electric Drill?

[Shanaly]

I guess we all use one for repairs and maintenance now and again!

Mine seems to have stopped working intermittently - I took it apart and cleaned off carbon from the copper motor bushes. but to no avail.

It has worked hard and the only other thing I can think of is dust in theres somewhere?

Any expertise welcome!

[Wotname]

Might help to know if it's battery or mains powered.
If mains powered, it is most likely a fault in the cord; either at one end or the other.
If battery powered, then crook battery, battery terminals or speed control circuit or trigger switch.

[bizzy]

loch the trigger on and lower it into sea water ,this will fix it !

[Shanaly]

btw it is mains 240V ~

[mrlassiter]

Shanaly,
Electric motors wear their brushes down to the point that they are not in spec enough to do their job, if you have cleaned carbon dust off the brushes it tells me they are worn (but, not how much,...) , try to get a set of replacement brushes from the manufacturer. I remember getting extra brushes included with some of the Harbor Freight tools I've purchased in the past, never ceases to amaze me that those cheap Chinese companies can afford to put them in the box, yet Dewalt?, nah!!

[Cormorant]

I recently revived a dead circular saw with a little PB Blaster into the trigger switch. . . .

[sdowney717]

Inside of cord may have broken copper strands which intermittently loose connection.

[xymotic]

All power tools can be fixed with a credit card. It's kind of hard to diagnose if you can't better explain the problem, though I suppose if you knew what was wrong there would be no need

When it stops working, if you tap it and it starts moving, that would indicate the brushes sticking. The power switch can be tested fairly straightforward with a multimeter.

[Reefmagnet]

At the price of them these days, why bother to fix one?

But the common problem is the power lead failing usually at or just below the point it enters the body of the tool. Usually way to test is to jiggle the lead with the switch pressed and see if it randomly starts operating. Also, if it's variable speed, it could be a failure in that circuit. If you don't need var speed, it can be by-passed.

One other check (aside from the obvious - the brushes and their tails): The commutator (where the brushes run) is made of segments of copper separated by insulation. In a dirty environment, or after heavy use carbon or other conducting material can build up in the gaps where the insulation is, effectively shorting the tool and preventing it from running. The usual fix is to scrape the gunk out with a thin blade, but CO contact cleaner might work.

If it's anything else and I reckon you just need to pronounce it dead