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I have a problem with my Delta DP-400 drill press.I am hoping one of the electrical experts on the forum can help.
When I click the switch off the motor keeps running. I tried getting a new switch for it but it didn't solve the problem.I have to unplug it to stop it.I followed all the wires I could see and found no shorts or bare wires.When I click the switch the light goes off but not the motor.Has anyone had a similar problem with their Delta ??

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Anderson Guitars
Clearwater,Fl. 33755

Dave...I've replaced 3 switches under warranty for a DP350. I actually had the opposite problem...the switch failed to turn the drill on. It was an obvious design problem with the switch and the customer service people eventually got it right.

While I know that this doesn't help with your problem, I can state that the customer service people were most helpful.

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JJ
Napa, CA
http://www.DonohueGuitars.com

Dave...sounds like a real problem. I would double check to see if some of the wires are worn to the point where the copper is being exposed. This could cause the a few wires to short together and bypass the switch. I have an older Delta drill press that I rebuilt and I can tell you that the motor, switch, and wiring is fairly straight forward so there isn't too many things that it could be.

By the way, did this problem just start happening or did you change something?

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Brad
Avon, OH

Thanks JJ, They told me the switch I received was an upgrade to my "obsolete" switch but it didn't solve the problem.

Brad, This happened a while back and I took the switch apart and cleaned it and it worked fine. Now it happened again and I can't get it to shut off.Very aggravating! I found no exposed wire to cause a short circuit but I'll check again.    Thanks guys

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Anderson Guitars
Clearwater,Fl. 33755

Have you tried just removing the switch? If you do and the motor still runs then it is a short. If it doesn't run then something is wired wrong or you have a bad switch. You should be able to just connect and disconnect the wires to your switch manually to see if it open and closes the circuit (turns the motor on and off)? Do you have 2 wires or 4 wires going to your switch?

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Brad
Avon, OH

Brad, I just went out and tried disconnecting the switch and it still ran. There are 3 wires going to the switch to two prongs. So, I must have a short...somewhere.

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Anderson Guitars
Clearwater,Fl. 33755

http://ecx.images-amazon.com/images/I/31880DCEG5L._SS500_.jp g

2 year warranty.
3/4 hp motor.

Hmmmm, can you take a meter and check to see where the power is coming from.   That's what I would do. My guess it's somehow feeding through the switch in the off position. Even new parts can be defective if from the same batch as the originals. I see this drill press is no longer available. Which is odd, maybe they are having problems with them? (rocket scientist luthier electrician here)

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http://www.dickeyguitars.com

Did you say that you took the switch out so all 3 wires were disconnected, plugged it in and the drill ran?  If so, you have two wires shorted together, the hot (coming from the cord) and the leg (going to the motor).  I have the same drill, and though I haven't taken the switch out, I am guessing that one wire is from the cord, one wire goes to the motor, and the third taps off the hot and goes to the light.  Take a good look and see if you can track the wires and look for any spot where they have rubbed together and possibly shorted.  That will cause the motor to run immediately when you plug it in.   On a side note, I have this drill and a shopmaster band saw.  The switch on the saw went bad two times and I finally threw their switch away and put a regular 20 amp toggle switch on it.  No more problems.  The switch on the band saw was a double pole 4 wire switch that switched both the hot and neutral.  

David, Yes exactly right. It ran with the switch disconnected. You are right on the wiring. I'll have to check the wires again very carefully and find the short. Thanks!

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Anderson Guitars
Clearwater,Fl. 33755

I believe These have a centrifugal switch in the motor and a run capacitor when you start you hear a click sound and when you stop you should hear a click if its working properly. The centrifugal switch is usually in the bell housing of the motor. These can get dirty or oily or just go bad causing them to stick open or closed. In the closed position current is flowing threw it. Yours might be stuck causing it to keep running. Sometimes taking the motor apart and cleaning with a electrical motor and parts cleaner can work. I'm not talking contact cleaner. Sometimes you need to replace the whole motor. It has been years since i have worked as an electrican so i'm very rusty and might be remembering something wrongly. So this is my theory.

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Guitars, guitars and more guitars.

Oh yeah this is what one looks like.

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Guitars, guitars and more guitars.

Yes Mike ,I do hear that click.I was wondering what it was.
You know,I was thinking too that with all the sanding and thicknessing I do on my drill press that the motor could be very dirty. Another good theory. Thanks!

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Anderson Guitars
Clearwater,Fl. 33755