3M AT-DIS7_PROHD manual Symptom Possible Cause Solution, Sander while the tool is running at, See

Troubleshooting Guide

Symptom	Possible Cause	Solution
		Check air line pressure at the Inlet of
	Insufficient Air Pressure	the Sander while the tool is running at
		free speed. It must be 90 psig (6.2 Bar).
		See the “Housing Disassembly” section
		for Muffler removal. The Muffler can
		be back flushed with a clean, suitable
		cleaning solution until all contaminates
	Clogged Muffler(s)	and obstructions have been removed. If
		the Muffler can not be properly cleaned
		then replace it. Replace Muffler Insert
		(See the
		“Housing Assembly” Section).
		Clean the Inlet Screen with a clean,
	Plugged Inlet Screen	suitable cleaning solution. If Screen
		does not come clean replace it.
		Install a complete set of new Vanes
Low Power and/or Low Free Speed		(all vanes must be replaced for proper
	One or more Worn or Broken Vanes	operation). Coat all vanes with quality
		pneumatic tool oil. See “Motor Disas-
		sembly” and
		“Motor Assembly”.
		Check for proper Motor alignment and
	Internal air leakage in the Motor Housing	Lock Ring engagement. Check for
		damaged O-Ring in Lock Ring groove.
	indicated by higher than normal air con-
		Remove Motor Assembly and Re-Install
	sumption and lower than normal speed.
		the Motor Assembly. See “Motor Disas-
		sembly” and “Motor Assembly”.
	Motor Parts Worn	Overhaul Motor. Contact authorized
		Service Center.
		Replace the worn or broken Bearings.
	Worn or broken Spindle Bearings	See “Shaft Balancer and Spindle Disas-
		sembly” and “Spindle Bearings, Bearing
		Shield and Shaft Balancer Assembly”.
		Disassemble, inspect and replace worn
Air leakage through the Speed	Dirty, broken or bent Valve Spring, Valve	or damaged parts. See Steps 2 and 3
Control and/or Valve Stem.	or Valve Seat.	in “Housing Disassembly” and Steps 2
		and 3 in “Housing Assembly”.
	Incorrect Pad	Only use Pad Sizes and Weights
		designed for the machine.
		Only use abrasive and/or interface
		designed for the machine. Do not at-
	Addition of interface pad or other material	tach anything to the Sanders Pad face
		that was not specifically designed to be
		used with the Pad and Sander.
	Improper lubrication or buildup of foreign	Disassemble the Sander and clean in
		a suitable cleaning solution. Assemble
	debris.
Vibration/Rough Operation		the Sander.
	Worn or broken Rear or Front Motor	Replace the worn or broken Bearings.
		See “Motor Disassembly” and “Motor
	Bearing(s)
		Assembly”.
		For SGV machines add extra washer(s)
	For vacuum machines it is possible to	to the pad spindle to increase the gap
	have too much vacuum while sanding on	between the pad and shroud. For CV
	a flat surface causing the pad to stick to	machines reduce vacuum through
	the sanding surface.	the vacuum system and/or add extra
		washer(s) to the pad.

34-8700-5191-8 Revision 10/03/07