Dewalt DC989 18V Drill- Sparks, smell

[Russprogress]

I just purchsed a USED Dewalt DC989 18V Drill as a backup to my everyday one. The used drill I purchased has a burnt electrical smell and a higher than normal amount of sparking at the brush area. The first time I operated it I actually had sparks exiting the case. The drill seems to operate properly : power, speed, except for the sparks and smell. Now that I have cycled it through the operations a little, the smell does not appear to be as bad, and the sparking is much less. However the sparks are continuous. My other drill gives off minor sparking when then the trigger is activated or released but not continuously. I am guessing this used drill needs a set of brushes but I am not positive. Can anyone with some knowledge help?

[milou6]

I have a DC759 that has all the same symptoms. Mine was purchased new about 3 years back, have taken relatively good care of it.

[cmoorejack]

hey guys,
You may have to replace the brush's on that one..part # 603754-01..the commutator [where the brush's may need to be cleaned also..could be build up and dirty] some of these cordless tools do have an odd ozone smell to them, nothing to worry about..the smell could also be coming from a switch starting to go bad..Anyhoo..check your brush's first..if they look ok..you may have a bad motor and will need to replace it..check your friendly neighborhood ereplacementparts.com for breakdowns,parts and availability...
Hope this helps..
Craig

[Russprogress]

Thanks for the info, I have ordered the brushes and will try to clean up the commentattor when changing the brushes. I assume you are saying that the smell may be coming from the switch......If that is the case I will only worry about the smell when it fails and just not use this drill indoors....the smell lingers forever. My biggest concerns right now are the sparks.....Hopefully the brushes help.

[milou6]

Yeah, thanks! Will give it a shot. For me the smell only began recently when the sparking started, so hopefully new brushes will sole the smell too (and yeah, it lingers alright!)

[blue2thabone]

Hello, i also have a DC925 and it does the same thing as mentioned (bad smell, smoking, and sparks), but i also now have a loss of power. The tool is pretty much useless. does this sound like a bad motor/brushes?

[Russprogress]

Just a note to update everyone.......I finally received my new brushes and was able to find time to replace them. Outcome: My old brushes were deffinately worn and both lead wires were chaffed through in several spots (against motor case). I should have probably replaced both lead wires, but I just wrapped them in electrical tape, I then installed the new brushes and reassembled the drill........The drill seems to be working properly now. I am not going to say that all the smell is gone, but I would say it is atleast 98% gone, (might still be burning off a little residual), but I dont think it is an issue anymore. As far as I am concerned the new brushes have cured my drill issues. Thank you for everybody's comments!! Russ

[milou6]

Just a quick follow up: I had commented about similar problems with my DC759, and wanted to warn anyone reading this thread with that model that it has a sealed motor and the brushes can't be replaced. The motor and pinion are relatively inexpensive though ($26) part number 397156-02.

[buildthings79]

Also one of the common factors of this problem is the trigger switch. DeWalt has issued a recall that was posted at the entrance to Home depot. The problem was the triggers in these drills would burn up very easily. The wires that go from the trigger to the brushes would be what starts that burning smell. The insulation on the wire heats up so much it starts to melt and catch on fire. I had this happen to me twice. It would most likely happen when I was using it under extreme load like in the hammer drill setting or to drill large holes through thick wood. There is reason why the trigger switch is covered in copper because it was designed to dissipate heat. If you use the drill at anything slower then full speed the trigger (which is a potentiometer or variable resistor) is then required to decrease the voltage to the motor but maintain the current. The excess voltage is dissipated into heat which is why the drill gets hot under heavy use. The wires that run up to the motor from the switch are under sized and over heat under the current demand which starts to melt the insulation off of them. This heat also causes the trigger to fail or at least the variable speed part of it. I have Three broken DeWalt drills with all the same problem. The newer drills have alot larger of copper wrapping on the trigger switch which will hopefully alleviate the problem. Oh yeah One thing that causes fires the most is DIRTY DRILLS. Hit your drill with a blow gun inside the vents and every now and then or take it apart and clean it.Fire needs Three things to start. HEAT, OXYGEN ,and FUEL. so if your drill has a crap load of saw dust and grease from the motor in it clean it all out so theres is nothing to heat up except the original factory parts.

[Dave]

buildthings79-

Amen to that advice.... cleaning out your power tools is one of the best ways to keep them working properly. A little compressed air goes a long way.