Not really understanding my Dewalt drill (speed control is gone)


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Old 11-04-17, 02:59 PM
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Not really understanding my Dewalt drill (speed control is gone)

I have a corded Dewalt D21008 (Type 1) drill that has been serving me well for years.

Suddenly, it lost it's ability to turn slower if I press the trigger just a little. There is no RPM control, but if I press the trigger in just a little, it is supposed to start turning, but slow. Instead, I press the switch about half way in and then the drill engages at full speed. Forward and reverse - no difference.

So I figured the switch was gone; so I get a new switch and replaced it. But the problem stays the same.

Confused; why would this be? What else could be gone on the drill so it does this? Might be time to let go of this but I'd like to understand it.
 
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Old 11-04-17, 03:12 PM
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I would look at the brushes.
 
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Old 11-04-17, 03:14 PM
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Sounds like the sped control switch has gone bad.
 
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Old 11-04-17, 03:40 PM
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There is a variable control that controls a switching triac. That triac has gone bad.
You need to replace the speed control assembly.
 
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Old 11-04-17, 03:42 PM
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Originally Posted by pugsl
Sounds like the sped control switch has gone bad.
That's the thing though; there is just one switch. Nothing else.

Hmmm brushes. I could have a look.
 
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Old 11-04-17, 10:33 PM
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It's the speed control...it's all part of the trigger assembly. You'll have to take it apart to understand. Here's a link to a replacement parts site...your part is #6. https://www.ereplacementparts.com/de...76_127136.html
 
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Old 11-08-17, 05:59 AM
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Yup, that is exactly what I replaced. :|
 
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Old 11-08-17, 12:03 PM
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Only other thing I could think of is a broken wire? No wiring diagram of exactly how the lead wires connect though. I'm not sure how brushes, as mentioned, would cause a problem like you describe.
 
 

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