PC Router revs up and down!

[betacrash]

I have just got me bot up and running since we moved it from another shop. Im trying to flatten my work surface. I put in a 1.5" planing bit and put the speed at 10,000. I start up the router and I hear it revving up and down up and down. Then it steadies itself then goes back up and down. I noticed through the little vent on the router that the sparking ring on the motor seemed a lot more noticable than before. What is wrong here?

[nschlee]

Check the brushes, could be worn and/or dirt between them and the rotor.

[dray]

Sounds like brushes

[betacrash]

Thanks for the info guys. Is there a specific place that I should buy the brushes or should I just buy the generic ones for sale on ebay?

[betacrash]

One more question. Is there a place where I can get instructions on changing the brushes? I was also thinking about changing the bearings as well. Thanks -shawn

[betacrash]

Alright, I dug into it myself and found out how to remove the brushes. The brushes are definitely worn, about 1/3 of its original length. Still dont know how to do the bearings, but anyway. I noticed that there is a slight groove worn in the armature. Is that normal? Its very slight. Sorry to keep replying to myself.