random orbital 150/3 eq sander problem

[GAMALS]

I have a random orbital 150/3 eq sander. The sander works good but the variable speed control stopped working. I called service/parts and the said it could be either the variable speed switch or the speed sensor on the armature.Variable speed switch is $50.00 plus.  The speed sensor I have to buy the whole armature $85.00 plus.The variable speed is easy to change, the armature is more difficult. Does anyone have a test or way to find out with part is failing?  Thanks  Jerry

 

[Administrator_JSVN]

Jerry, is your sander more than 3 years old? If not, it's covered under warranty. And, welcome to the forum.