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Pencil Sharpener Repaired

By Jestine Yong on March 11, 2015

My pencil sharpener quit on me – I know they are cheap little things, but I have gotten spoiled by it and want it fixed. This is the first time I have ever opened one of them up.

It uses 2 AA batteries. Although I just bought it a few months ago, it seemed like it was working harder than it should have to; and the batteries seemed to run down a little quicker than I believe they should. So hopefully I may be able to do something to help prolong the life of the batteries.

The large gear was completely dry and had no grease at all! That is where the extra friction was coming from and causing the motor to work harder than it had to. That is what was causing it to run down my batteries faster than I thought they should be. I knew something was wrong, and I was right.

The black pin that goes through the center of the large gear is the one that fits on the end of the razor blade. If it gets pushed down it will push the little cap off of the contacts, (as seen in a previous picture) and cause the motor to shut off.

I thought the sharpener was working harder than it had to, and I was right. It was either an accident that it had no grease, or it was deliberate. Either way, it will have grease on it when I put the unit back together.

There are no identifying numbers on the motor. I measured it’s resistance to be 0.94Ω. Looking at the gear from the front, the motor turns clockwise.

I put some good dielectric grease on the gears before installing them. Dielectric grease is not electrically conductive. So even if some gets splashed around it won’t cause any connections to short.

This article was prepared for you by Robert Calk Jr. He loves learning electronics and device repair.

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Pencil Sharpener Repair

10 Comments

Mohammed kasim C.M

March 12, 2015 at 3:05 pm

Nice article. How can I distinguish electrical grease from dielectric grease. I have a white coloured grease( Panasonic white grease in small tin).is it electrical grease?

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- Robert Calk
  
  March 13, 2015 at 9:33 am
  
  Thanks Mohammed. If it is electrically conducting grease it should say so on it. Mine has carbon in the grease. Most thermal grease is not electrically conductive.
  
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Yogesh Panchal

March 12, 2015 at 4:34 pm

Good fix sir keep up sharing.

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- Robert Calk
  
  March 13, 2015 at 9:34 am
  
  Thanks Yogesh. I will keep on sharing.
  
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dicksy

March 20, 2015 at 2:02 pm

hi mr calk good article and nice pics
thanx

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- Robert Calk
  
  March 21, 2015 at 1:51 pm
  
  Thanks Dicksy. I almost didn't send it in because it is so simple. But it is kind of interesting. I was hoping some of yall might like it.
  
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Anthony

March 23, 2015 at 5:21 pm

I always enjoy your adventures in electronics Robert and the pictures you provide are excellent ! Great result again as usual mate !

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- Robert Calk
  
  March 23, 2015 at 11:44 pm
  
  Thanks Anthony, I appreciate it.
  
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Humberto

March 27, 2015 at 8:48 pm

Hi Robert, good article, nice photos with excellent explanations.

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- Robert Calk
  
  March 28, 2015 at 9:38 am
  
  Thanks Humberto.
  
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