Fixing this Griot's G9 polisher

[brad hays]

I have a Griot's G9 Random Orbital Polisher I got off ebay a few months back and didn't actually plug it in til this week. Turns out it doesn't give any indication of wanting to work at all. Motor brushes seem to be ok and I have no idea what to look for next.

Any advice on what to check next on this thing to get it running again?

491438

[Richard Coers]

Get a multimeter and check where the electricity is at and where it ain't. My guess is switch, but could be a broken wire in the cord, or a problem with the armature windings.

[brad hays]

I've checked continuity in the power cord all the way up to the part I'm holding, which is the trigger switch itself with the power cord input leading in from above. Which parts should I get the probes on when I'm working the switch and testing for continuity?

491456

[Tom M King]

First check the blue to either, or both whites and see if power is getting there. If not, check the blue to red. Let us know the result. Put the switch to the on position, or try it in both positions if you don't know.

[Kevin Jenness]

If the warranty is in effect why not send it back for replacement/repair?

[Tom M King]

Bought used off ebay, I doubt there is any kind of warranty existing. If power is getting to the speed controller (potentiometer) spin the dial back and forth fast several times and see if there is any output through it, if there wasn't to start with.

[Tom M King]

Probably something like this- except yours doesn't have a sliding potentiometer part:

https://www.diynot.com/diy/threads/wiring-of-trigger-circuit-for-cordless-drill.259590/

[Dan Cameron]

Probably something like this- except yours doesn't have a sliding potentiometer part:

https://www.diynot.com/diy/threads/wiring-of-trigger-circuit-for-cordless-drill.259590/

And his unit is not battery powered.

[Tom M King]

Still two lines in for power though, and two lines out somewhere to the motor.

[Richard Coers]

Still two lines in for power though, and two lines out somewhere to the motor.
Not if he is checking the switch. The hot is interrupted by the switch. Switch has failed, no hot to the motor.

[Tom M King]

Or it could be the pot. If the pot has failed, switch may be furnishing hot to the pot, but pot not sending power to the motor. It doesn't matter what the power source is, or what type of potentiometer it has. Check first between the switch and pot. If no hot then it's the switch. If the switch is making the line hot to the pot, but no power out of the pot, then it's the pot.

[brad hays]

After this last round of testing I'm guessing this switch is actually working like it should. The black and blue wires share the same terminal. When the switch is off the left white and black wires show no connectivity, but when on they do. Since this is reaching the edge of my electrical / motor construction experience I'm thinking I'd be better off just getting another one rather than having to be hand held through more testing.

[Tom M King]

Answered this on Woodtalk