Porter Cable 18V drill has power but doesn't spin

[Uncle Ben]

I have a 18V Porter Cable drill that has worked great for quite a few years, but suddenly stopped working. I have a 2nd PC drill and an impact that also use the same 18V batteries and they work fine, so I know the battery is not the issue. I know the drill is getting power because the LED work light on the front of the drill comes on when pressing the trigger, but the drill does not make any sound whatsoever and does not spin. It does not buzz or squeal in any way when pressing the trigger...nothing, except for the LED light coming on, which makes no sound.

It is past the warranty, so I don't think Porter Cable can help me, but I am willing to take it apart and replace parts if needed, but I would like to have some direction or idea of possible issues before I do anything, especially since I have never taken apart a drill before (I have taken lots of other things apart though )

Thanks for any and all input!
-Ben

 

[Bubba Fett]

Probably a loose connection somewhere between the trigger and the motor. I'd open it and look for anything dangling. I'd check any connections for corrosion or dirt. If it isn't that, than there could be a logic board issue. The motor itself might be bad, but it never hurts to check for easy stuff. A multimeter would be handy for checking continuity between connections.

 

[ybnormal]

is that the old 18v NiCad model? I've got two of those and they are pretty durable. as BubbaFett said, sounds like you have a loose connection to the motor or the circuit board

 

[Uncle Ben]

Yes, I believe it is NiCad, and it has performed very well up to this point, as has my other drill and impact of the same 18V type. I have been very happy with them. I will go ahead and open it up and start by inspecting visually and then checking continuity, etc. Thanks for your input.

 

[Bacon!]

With a brushed drill it is a pretty simple circuit. After a visual inspection for broken wires, etc., use a multimeter to see where power stops.

It'll be going into the the transistor module, which is often (but not necessarily) part of the trigger module, then out to the motor, plus second switch for the light.

If not making voltage past the transistor then the transistor itself is fried or the trigger, which "might" be able to be cleaned out as it is a type of potentiometer with a track/wiper contact (usually). Could also be a bad solder or crimp joint.


If near 18V is making it to the motor (trigger fully depressed), then a motor fault. Maybe bad brushes, maybe they're replaceable, or maybe not, or a bad winding. Could even be a bad spot on the commutator, then manually turning the chuck to put the motor in a different commutator position (and /or powering a different winding) could allow temporary function, be a sign to tear open the motor or replace.