The electronic brake does not work

The best place to find parts for your particular model is here:
Porter Cable Parts

Imhope,this helps you!

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Power Tools - Porter-Cable

www.portercable.com/20Volt

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The battery is defective.

go to www.dewaltservicenet.com and enter the model number of your drill. It will get you to the parts breakdown and will tell you if there is a charger available from the factory. Or call 1-800-433-9258 1-800-4DEWALT. stanley black and decker owns all of them so yes that's the right place!

Usually when the driver is slightly bent, it will not retract. Easy to check. Remove the head and pull out the cylinder and driver together. Adjust the driver or replace as needed.

There is a good parts breakdown for this drill on www.ereplacementparts.com. They are also a fairly good place to get replacement parts but most of the parts for this drill are discontinued.

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Here's a link for PDF file download of your manual.

http://www.dewaltservicenet.com/documents/English/Instruction%20Manual/Porter-Cable/N027636,DA250C.pdf

if you are talking about the J621 3/8 Professional drill the chuck kit number is 692074 and it lists for 43.30. You can but that from Dewaltservicenet.com or if you need more assistance let me know.

Most chucks have a tolerance the cordless drills where designed for drill bits 1/8 and larger the 3/8 chucks are a little better with the smaller bits .Check your owners manual and see if they have a min requirement listed for the bit size