Winter maintanence time. I have two sanders, an older heavy duty Dewault and a Harbor Freight. Both can be tempermental to start…usually at the beginning of the day. I’ll spin the pad while triggering and eventually they kick on. Once they have run a few moments they are good for the rest of the day. Would this symptom tend to be the trigger or the brushes or some other componant? I do always blow them out wuith air at the end of the day. Thoughts?
I’ve used 3 sanders that the triggers went out with the same problem you describe but the problem was constant and the machine would run intermittent all day. Also you spinning your pad and it will then start running would suggest its probably more of a motor problem or brushes. Could be as simple as a loose connection inside from blowing them off.
The carbon brushes are cheap and the easiest place to start. You can also try to clean them by scrubbing them on some sandpaper to get the glaze off them.
They are not a complex design and take about 15 minutes to tare the whole thing down. Testing the connection at the trigger is pretty simple with a volt meter.
Where are you located?
Probably dust collected on the brushes, that’s the second problem.
…the problems are: 1-too much dust on brush conducts, as Ghettorat said; 2-one of the brushes is wear out; 3-problem on the points spring and points.
Solutions: for the 1, clean; for 2, change the brush or if you are in a hurry and needs to sand, put that brush (that normally is the under side one) on top and the other there; for the 3; screw out one of the sides of the tool then screw out the box that have the points then check the action of the spring and that all have good contact and action. Snad the points (that I bet are Black) with 500 grit.
-I use the best that is an old Japanese Makita; years and years without “winter break” as you said; I make a living from this labor so the tools should be always ok.
Pull the brushes. If they’re worn 1/2 way; replace them. Supposed trigger problems are almost always brushes. Brushes are a cheap fix.
Brush and dust problem likely, but it’s sometimes carbon build-up on the commutator from the brushes normal wear. Always blow out the areas thru the motor vents very thoroughly, and spend some time doing it after each use. Never sand brushes, they’re shaped for the armature and will spark and arc if you change the curvature on the faces. This causes excessive current which can kill the motor by overheating it. If there’s any issue with the brushes (even new ones), always replace them. You have to remove the motor armature to clean/surface the commutator and you need to know what you’re doing since most of tool has to come apart.