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General Category => Ask Steve a question. => Topic started by: sweet saw on October 21, 2016, 06:34:42 pm

Title: 788 dewalt
Post by: sweet saw on October 21, 2016, 06:34:42 pm

saw speeds up and slows down .speed control set at 6.   

Title: Re: 788 dewalt
Post by: DWSudekum on October 21, 2016, 06:46:28 pm

This probably will turn out to be the motor.  The electronic circuit board on the 788 is well designed and seldom goes bad short of something like a voltage spike from lightning or something like that.  That has been my experience any way.

DW

Title: Re: 788 dewalt
Post by: Wooden Lace on October 21, 2016, 08:12:42 pm

Hi could be the brushes or even the foot switch, if you are using one.  One of my 788's did that and my research indicated the brushes probably needed replacing, which I did, but it turned out to be the foot switch connection.
Nancy

Title: Re: 788 dewalt
Post by: sweet saw on October 23, 2016, 09:42:01 am

THANKS, not the foot switch,I am going to try brushes next.

Title: Re: 788 dewalt
Post by: sweet saw on November 12, 2016, 08:08:37 am

Took it to service center and it was the motor.

Title: Re: 788 dewalt
Post by: DWSudekum on November 12, 2016, 08:54:21 am

Quote from: sweet saw on November 12, 2016, 08:08:37 am

Took it to service center and it was the motor.

Glad you got your saw fixed.

What i have found with the DW788's motor is that because it is totally enclosed, that is there is no openings for the carbon brush dust to leave that it will accumulate and eventually short our the commutator of the motor.  The fine carbon particles that get worn off the brushes will eventually accumulate between the fingers that the brushes ride on and cause shorts between the segments.  This is a fairly common problem with this type of motor. 


DW