Grizzly 6" Jointer Hum

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Forum topic by Rob posted 05-03-2010 01:41 AM 3320 views 0 times favorited 31 replies Add to Favorites Watch
View Rob's profile


22 posts in 3224 days

05-03-2010 01:41 AM

I just bought my first jointer on craigs list a few weeks ago and on the third project it crapped out. it blew my breaker and now just sits and hums when I hit start. I have heard it may be the starter motor capacitor so I just now pulled it out. it doesn’t look or smell burned, how do I test this thing and is it a common problem on the G0452 jointer?

-- Rob in Texas

31 replies so far

View TheDane's profile


5575 posts in 3901 days

#1 posted 05-03-2010 02:20 AM

I have a G0452 … I have been delighted with it. Even though you are not the original owner, I’d contact Grizzly tech support … in my experience they have always been very helpful.

-- Gerry -- "I don't plan to ever really grow up ... I'm just going to learn how to act in public!"

View barryvabeach's profile


159 posts in 3282 days

#2 posted 05-03-2010 02:43 AM

Rob, you might want to look around OWWM, while your Grizzly probably doesn’t qualify, they often talk about diagnosing motor problems. I did a quick search and came across this post which ids the suspects

Here is another post that talks about how to check the capacitor with a multi meter

View Rob's profile


22 posts in 3224 days

#3 posted 05-03-2010 03:20 AM

Just sent an email to Grizzly tech support, thanks for the recommendations!

-- Rob in Texas

View ajosephg's profile


1880 posts in 3799 days

#4 posted 05-03-2010 03:38 AM

If it’s the capacitor, that would be a cheap fix, and you wouldn’t need a new motor.

Any electric motor shop should be able to fix you up.

-- Joe

View richgreer's profile


4541 posts in 3313 days

#5 posted 05-03-2010 02:51 PM

I also have the G0452 and I have never had a problem with it.

-- Rich, Cedar Rapids, IA - I'm a woodworker. I don't create beauty, I reveal it.

View Knothead62's profile


2600 posts in 3199 days

#6 posted 05-03-2010 11:13 PM

A good motor shop should be able to repair or replace the motor. Grizzly should be able to give you some direction on what to do. Good luck!

View oldcans's profile


22 posts in 3253 days

#7 posted 05-03-2010 11:32 PM

You may want to check that you can turn your blades by hand. If a scrap of wood somehow got jambed in the head it would cause the motor to humm and trip the breaker

-- Dan, quartersawn oak = oak with stretch marks

View mchuray's profile


81 posts in 3237 days

#8 posted 05-04-2010 01:12 AM

To test a capacitor put the scale of a VOM om ohms andd put the leads across the capacitor and hold the a while. Then reverse the leads. The needle should jump (on a digital meter the numbers will show a reading then drop to OL). The capacitor is a really easy and cheap fix if that is all that is wrong.

View MedicKen's profile


1615 posts in 3701 days

#9 posted 05-04-2010 01:17 AM

Are all the connections tight? A loose wire can cause similar symptoms

-- My job is to give my kids things to discuss with their

View Luke's profile


545 posts in 3532 days

#10 posted 05-04-2010 01:38 AM

We had lots of lightning here recently, perhaps it got fried?

-- LAS,

View SteveMI's profile


1128 posts in 3533 days

#11 posted 05-04-2010 01:47 AM

My HF DC did the same thing recently. Took the capacitor to a Heating and Cooling supply house where they checked it, confirming it was bad. Reading the specs on the side of the capacitor they were able find a new one in stock under $10.


View Rob's profile


22 posts in 3224 days

#12 posted 05-04-2010 02:31 AM

i was pleased to see this email in my inbox this morning from Grizzly, so rushed home to do the test.

Thank you for your email dated May 1, 2010.

I am sorry to hear that you are having problems with your motor. There are several possibilities that could cause the problem you described: The motor may have improper voltage supplied to it, the start capacitor may be bad, the contact points may need cleaned and adjusted, or the motor may be burnt out. Below, please find instructions for checking these areas. Please, before you work on the motor, be sure to unplug the unit from the power source.

If possible, start by verifying that the voltage supplied to the motor is correct by testing it with a meter.

If the voltage is correct, I recommend inspecting the start capacitor. The capacitor is normally located under the dome-shaped cover on the side of the motor. It is a cylindrical part that has two wires attached to it. Please look for any signs of a waxy substance leaking from it or any deformities to its shape, such as bulges or holes.

If necessary, you may also take the capacitor to a local motor shop to have it tested or test it yourself if you have a capacitance meter. Before handling the capacitor, use an insulated screwdriver to short the two wires, which are attached to the capacitor, together. This will discharge any energy being stored in the capacitor.

Please let us know if the capacitor has any of the preceding problems. We would also need to be provided with the numbers that are printed on the capacitor so that we can assist you in obtaining a replacement.

If the capacitor appears to be in good condition, I recommend inspecting the contact points. The contact points are located in the back of the motor at the motor fan end. Start by removing the fan cover and fan. Sometimes, there is a metal dust cover behind the fan. If equipped, remove the cover. You will then find a centrifugal switch mounted onto the motor shaft. You will notice springs on this switch. The centrifugal switch can be removed by loosing the setscrew that holds it fast to the motor shaft.

Once this switch is removed, you will see the contact plate. In the center of the contact plate, you will notice a part resembling a wavy washer. One side of this part is a pivot point, and at the other side are two small contact points. They look similar to a watch battery in size and shape. Inspect these points and the corresponding points that are on the centrifugal switch. The flat surface of the points should be shiny. If the surface appears black, it can be cleaned with a small, flat file or a piece of sandpaper.

After the contacts are cleaned, you may install and adjust the centrifugal switch back onto the motor shaft. When the switch is adjusted properly, it will press against the part that resembles a wavy washer until the contact points make a flat connection. Once the points are touching one another, tighten the setscrew for the centrifugal switch. You may then power up the machine and test the motor only for a short time or reinstall the fan and fan cover to finish the reassembly. Once the reassembly is complete, the machine can be test ran.

The motor may be burnt out if the problem is not being caused by the voltage, start capacitor, or contact points. If the motor is burnt out, it requires replacement.

If we may be of further assistance, please do not hesitate to contact us. You are a valued customer, and we look forward to serving your future woodworking and metalworking needs.


Technical Service
Grizzly Industrial, Inc.
EN #792

-- Rob in Texas

View Rob's profile


22 posts in 3224 days

#13 posted 05-04-2010 02:52 AM

So I started the procedures from the email/ First i tried 3 different outlets all on different circuits, same result – motor hums and kicks breaker after about 5 seconds. Volt meter in the outlet says I have good voltage. Motor is not seized and spins freely.

Next I removed the capacitor cover:


Then the capacitor:

I had already removed the capacitor yesterday and it looks good. No bulging, no signs of damage:



-- Rob in Texas

View Rob's profile


22 posts in 3224 days

#14 posted 05-04-2010 03:07 AM

I tested the capacitor like mchaury suggested above – put ohm meter across contacts and let it settle, then switched the leads and it jumped up then settled again – not OL, but a small number. I don’t know what scale I was on, but still going off the fact that the capacitor shows no signs of damage I still assume it’s good.

So I go on to check the contact points like Grizzly describes in the email. So I start at the fan end of the motor and remove the cover:

Then the fan:


and what I assume is the metal dust cover they refer to:

The I look for the centrifugal switch mounted onto the motor shaft, but all I see is this bearing:
Grizzly G0452 6" Jointer Motor

And all of these burnt wires:
Grizzly G0452 6" Jointer Motor

Grizzly G0452 6" Jointer Motor

Grizzly G0452 6" Jointer Motor

I never found the centrifugal switch or the setscrew, but after seeing the wiring, I’m assuming the motor is fried. This may be my first time being ripped on a craigs list purchase, but I don’t know if the seller did this or I did. After all I tested it at his house, rann a few boards through it at my house before it bit the dust. I was in the middle of jointing a very small cut off the edge of a 1.75” wide pine board when it died, so I’m pretty certain I didn’t overstress it.

I’m sending the pics to Grizzly and see what the ask for a new motor.

-- Rob in Texas

View mrg's profile


850 posts in 3238 days

#15 posted 05-04-2010 05:50 AM

Rob, call an electric motor shop you can probably have the windings done for under $100 dollars.

-- mrg

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