110.67732794 Kenmore 70 series dryer not starting, just makes humming noise when Start pressed

[ftrbreed]

Model Number

110.67732794

Brand

Sears Kenmore

Age

6-10 years

Hey all, I have a Kenmore 70 series electric dryer model number 110.67732794 . I've done a couple repairs on it already in this saga so I'll go through them below. To summarize though, when I press the Start button, I hear the hum like it's trying to start, but it doesn't kick into motion with spinning or anything.

First off, before doing any testing at all with a DMM etc, my partner had recommended we replace the thermal fuse as that was a common issue with these dryers. I replaced that, still had the same result afterwards.

Then I got a DMM out, tested connectivity and everything looked good for the thermal fuse, the start button, the door latch. When I turn the timer to say... 30 mins, I do indeed hear it ticking. And as you'll read in a moment, other repairs momentarily made the dryer work so I'm not sure whether or not the timer is suspect at all.

At that point, I took off the back panel entirely and noticed the right-most power connector had the wire melt completely through the insulated sleeve and some burning on it. I had assumed that the power cable was at fault, picked up a new one at home depot, swapped it out, and YES the dryer worked!

I ran one load of clothes to dry overnight. I babysat it for 30 mins, and everything seemed fine, heat was being produced and vented, etc. Went to bed. Woke up, and the dryer is back to not starting (just humming when Start is pressed), and it seems like the clothes didn't make it to the end of the dry cycle as they were still a bit damp.

Any ideas here? Am I looking at potential motor issues or some other more obvious thing I need to test with my DMM?

 

[Jake]

When you replaced the power cord did you replace the terminal block kit as well? You always need to do that when one of the HOT wires Burn off there.

I see that happen a lot too, look here:
(click to enlarge)


Here's the dryer terminal block kit for your model:
Terminal Block Kit 279320


The first thing I always do is use my multimeter to do a volt test at the dryer terminal block, where the power cord connects to it.

First make sure your getting 230-240 volts at the terminal block in the back of your dryer. The outer wires are hot, middle wire is neutral. So put your volt meter probes on each of the two outer wires at the terminal block and see what your meter reads, you should get 230-240 volts between the two outer wires on the terminal block.

Let us know what you find.

Jake

 

[ftrbreed]

I did not replace the terminal block, no. I'm at work now so won't be able to do the voltage test until tonight, but until then, this is a pic of the terminal block before I replaced the power cord. As you can see with the right-most connection, the screw is stripped to hell too. It seems the prior occupant who first purchased this dryer may have had problems in the past is the best guess we've had.

 

[Jake]

Yes, I see that clearly. I've seen many the same way in the last 35 years of running local service calls. I always replace the power cord and that terminal block kit with the new wiring, all clean electrical connections are very important.

Jake

 

[ftrbreed]

Looping back. I tested the terminal block wires - approximately 238.8~ volt readings for the two outside wires and about 120~ volts for outside + middle wire combo, so that all sounds good.

I did try starting up the dryer again this morning, and it worked. Theory - both times I've witnessed complete shutoffs with no restart for a while were when I had run a pretty full load of clothes with the temp on High. And note I did already replace the thermal fuse. Does that give any hints at what may be happening here? Thanks

 

[Jake]

When you start the dryer, does it make a grinding sound? If so, your motor bearing has gone bad and that's why its shutting down.

When you try to immediately start your dryer after it shuts down, does it start? If not, then it could be just overheating and shutting down, lint build up on the motor and in the motor breather vents will cause this.

Here's the motor for your model(Video Included):
279827 Dryer Drive Motor


The video when you click the link to the motor will show you how to access it to check for lint build-up on it, and it will also show you how to replace it.

Jake

 

[ftrbreed]

Another update, sadly still in a bad state, though the insider of this dryer is a lot cleaner now.

I got to the motor and found quite the mess (attached). Did a lot of vacuuming and air dusting, got things looking pretty good. Put everything back together, started up, and yes! Dryer was drying again. For about... Maybe 50 minutes. Then the dryer stopped mid cycle and all the sound left was ticking from the timer. I pressed start again immediately after, and I could hear a higher pitch buzz/hum of it trying to start but it wouldn't take.

Waited an hour, went back, it started again. 10-15 minutes later, back to not running mid cycle. Couple more bouts of that, and now it isn't starting up, just the high pitch buzz/hum and nothing.

At this point, if I'm looking at a motor replacement, we will probably just be in the market for a replacement dryer, but if you have any other ideas, I'm all ears! Thank you

 

[Jake]

Its a bad motor for sure.

Jake