Repairing a Dremel 4000




Introduction: Repairing a Dremel 4000

About: DIY guy || electronics enthusiast || College dropout

So someone at my workplace accidentally plugged my 110v rated Dremel 4000 to a 220v source. With the amount of smoke that came out, I was pretty sure it was a goner.

But I attempted a fix anyway and guess what, those Germans sure made one hell of a machine. Everything is modular and repairable, gotta love precision German Engineering :D

Step 1: Google It: Is It Fixable?

The Dremel 4000 is one of the most popular tools for makers and hobbyists out there. So there's plenty of resource online to fixing it. The best one to find out exactly what's wrong with your Dremel 4000 is eReplacement part's page on dremel parts. Just look replacement part by symptoms and you'll have a general idea on what might might have gone wrong.

iFixit's page on the Dremel 4000 is a great resource on how to take it apart. I did try asking on iFixit's forum on asking about my problem directly, but it went unanswered till this day.

After a moderate level of looking around, I was pretty sure it was my electrical assembly that died out. I would also need to check the coils if they burned out too by any chance.

Step 2: Taking It Apart

So now to take it apart. iFixit has quite amazing documentation on how to take the dremel 4000 apart. Just follow through step 1 to 14 from here and you'll be done in no time.

Step 3: The Fried Electrical Assembly

It was pretty obvious from the looks of it what I was dealing with here. But just to make sure if it was just the electrical assembly, we need to check the coils.

Step 4: Checking the Coils

After doing a continuity check on the Secondary coil and the armature, I was convinced they were fine. And it was just the electrical assembly that needed replacing.

Step 5: Ordering the Electrical Assembly

I ordered the electrical assembly from amazon

1) Dremel Electrical Assembly

Step 6: Parts Delivered: Ready to Repair

So after waiting aroud 3 weeks for the Electrical Assembly to ship to my country, we're finally ready to bring this Dremel 4000 back to life

Step 7: Electrical Assembly Connecting Guide

So there's not much information well documented on connecting the three electrical assembly wires. I had to do alot of digging around until i finally found a video explaining the whole thing in detail. There are three wires in total.

1) The red wire (connects to the top connector of the Secondary coil)

2) the Black wire (connects to the bottom connector of the Secondary coil)

3) The Blue wire ( latches onto the bottom part of a plastic hinge connecting to a metal connector)

A special thanks to TXW5CSM for his video on explaining the mystery of the blue wire.

Step 8: Place the Electrical Assembly on the Right Slot

There are grooves to hold the electrical assembly in place. Place it in gently and it should fit right in.

Step 9: Connect the Red Wire

The red wire connection is pretty straight forward. Just connect it to the top connector of the Secondary coil. Make sure to route the wire from below the screw terminal, or the top plastic cover of the Dremel might damage it.

Step 10: Connect the Black Wire

To connect the Black Wire, you'll need to lift up the Armature assembly. It's pretty straight forward after that. Just connect it and like the previous red wire, route the wire through the space beside the plastic screw terminal.

Step 11: Connect the Blue Wire

Now the tricky one. Connecting the blue wire. for this you'll first need to disconnect the metal terminal with the capacitor attached to it. Then gently place the blue wire's metal connector onto the plastic ledge just beneath. ( shown in the picture)

After that, route the wire through the space beside the plastic screw terminal and re-attach the metal terminal to the secondary coil.

Step 12: Connecting the Power Cord

Connect the power cord and slide the electrical assembly back into it's slot.

Now we're ready to put everything back together.

Step 13: Placing the Power Button Assembly in Place

Place the Power Button Assembly in place. The small notch should place just on the switch ( as shown in the picture)

Step 14: Placing the Speed Controller in Place

Attach the cover to the speed controller. It has notches to fit the PCB.

Place the speed controller in place. One end of the Power Button Assembly sits into the plastic knob of the Speed Controller.

Step 15: Putting It All Back Together

Now to put it all back together and see if it runs :)

Step 16: The Smoke Test

Make sure to plug in to a 110v source! (Not making the same mistake again) and see if any smoke comes out.

If everything went well, your Dremel should be as good as new :)

Here's a link to my google photos Album for the project, if you guys need it.

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    Question 1 year ago

    How do you take the armature apart