# G400 question



## Martin22250 (Jan 19, 2017)

I have a less than one year old g4003g, it sounds like the motor has a rattle noise that don't change with spindle speed, same noise wether full speed or 70 rpm. Check motor mounts and belt tension, and the thin motor cover for the power wire is tight also, works fine just has me curious. Also my machine has a light hum even when the red power button is pushed in, I just keep the breaker off when not using it to be safe.
Don't know how to fix my title heading I left out part of my model letters


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## tmarks11 (Jan 19, 2017)

The hum is due to the control power transformer, which is always on.  It takes 220V and produces 110V (for control power to the switches) and 24V (for the halogen light).

Doesn't really hurt anything to leave it power, but it is annoying.  Would be nice if the e-stop switch had a spare contact set that would switch it off.

rattle noise independent of spindle speed sounds like sheet metal vibrating.  Check your back splash screws?


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## Martin22250 (Jan 19, 2017)

tmarks11 said:


> The hum is due to the control power transformer, which is always on.  It takes 220V and produces 110V (for control power to the switches) and 24V (for the halogen light).
> 
> Doesn't really hurt anything to leave it power, but it is annoying.  Would be nice if the e-stop switch had a spare contact set that would switch it off.
> 
> rattle noise independent of spindle speed sounds like sheet metal vibrating.  Check your back splash screws?


Thanks for your reply,  I'll check it out


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## Bob Korves (Jan 19, 2017)

Might be a loose fan in the motor.  Watch the belts run on the motor pulley and see if there is a problem with the belts jumping around or the pulley being loose.


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