Tip & How-To about Heavy Machinery

How to replace a capacitor on an electric chipper or shredder

Symptom: the motor makes a loud humming sound and will not turn
Tip: check the capacitor to see if it has burst - if so, replace
. unplug shredder, open it; undo retaining screws for motor housing
. unscrew old capacitor, replace with a similarly-rated one e.g. 16mF 440V ac like Maplin RG67X which is less than 10 dollars

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4 Answers

klh powered subwoofer model ASW10-120B... when you plug in to power... it makes a loud buzzing/humming noise

I would check the caps on the power supply. They are rather large electrolytic capacitors that will look like they burst and/or leaking. When these die, the caps ground and the sub will make a loud buzzing sound. If you are handy with a soldering iron you can replace them yourself. Replace them with the same voltage or a little bigger and same with the size.

If the cap. says 16v 4700pF on it, for example, a 20v 5300pF or a 16v 6200mF cap. will work for this application.




Jan 05, 2016 | Audio Players & Recorders

1 Answer

checking a capacitor on a liftmaster

If the capacitor is bad the motor will not run and you will have a loud hum when you try to use your opener. What is the symptom you are having?

Mar 29, 2012 | Sears Craftsman LiftMaster Chamberlain...

1 Answer

My dental compressor stopped working. What can I do?

Does it make any noise at all? If not, check the motor for a protective device. A thermal reset would be a red button on the end of the motor. It may be as simple as that.

If it hums loudly, and turns over by hand- no power applied- with difficulty the motor bearings or compressor bearings may be needing attention.

If it hums loudly and barely turns, but turns by hand freely, the motor has a start/run capacitor- it likely failed. Replacing the capacitor is a simple task- just make sure to replace it with one of similar ratings.

Feb 14, 2012 | Air Tools & Compressors

1 Answer

Hi I have a Brivis buffalo 80 heater,16 years old normally goes well. Piolet light lights and stay alight. Main burner starts up but when fan should come on all I get is a loud ac hum at the unit.The fan free wheels. Is there a solinoid that opperates the fan and where is it on the unit if that is likely to be the problem.

There is. Unfortunately it is on the main circuit board. To check pull the circuit board out and examine the bottom in search of a scorch mark where the circuit has overheated and burst. If so, replace the board.
Usually if I hear that hum it means the motor itself has burned out and needs to be replaced. since the squirrel cage spins free, it's possible that the motors capacitor isn't right, which caused the eventual burnout. be sure to check that if you replace the motor, just read the motor for the number and use a multimeter to check the capacitor. best of luck to you.

May 07, 2011 | Heating & Cooling

1 Answer


You must see if this is the hum of the motor or that of a mechanical friction of the motor assembly. If the motor is humming please check the capacitor that is connected to the motor, change with the value specified on the capacitor.
If there is hum on the drive use good lubrication remove and reset.use degreasing spray to ease off friction

Sep 24, 2010 | Kitchen Ranges

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