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FIXED Kenmore 90 Series Dryer - Won't Start

Kendall

Premium Member
Joined
Oct 25, 2010
Messages
33
Location
Southern Oregon
Model Number
110.66902692
Brand
Sears Kenmore
Age
6-10 years
Good morning,

I bought the unit used from a dealer. I had to guess on the age.

Cutting to it...

Won't start

220V fully verified into back panel, i.e. 121V Black to White, 121V Red to White & 242V Black to Red

Fuse, Thermal Cutoff, Operating Thermostat and Coil all have continuity. Well... the coil has a little resistance, but...

Start Switch and Door Switch have continuity when engaged and light works accordingly.

Belt is good. Drum seems to turn smoothly and belt turns with it. I can't see it, but I would think if the motor were frozen, the drum and belt wouldn't turn without some pretty serious effort.

For testing, I removed both red wires from the Operating Thermostat that sits atop the exhaust manifold about 6" to the left of the coil. My schematic does not show the 2 violet wires on this thermostat. Only the red and red/white. I'm ASSuming that the violet wires that terminate into thin air on the schematic are the violet wires I'm seeing at the relay.

Here's the weird part... to me, at least...

Timer Off - 121V at 12ga Black wire (middle right of timer.) No power to either side of the coil circuit. Good!

Timer On - 121V now also at Red 12 ga wire (bottom right of timer)Timer does not move or tick after pushing and releasing Start button. Unit does not start. 70V registers on the incoming wire to the Operating Thermostat as well as both of the violet wires. Nothing from the other side coming into the coil When connected, 70V can be found anywhere in the coil circuit.

Timer On and holding Start button down - Timer clicks and then begins ticking with a sound I would normally expect. Still nothing coming in from the other side of the coil. Voltage on the incoming wire to the Operating Thermostat now 83. However... the right, purple wire is now dead and the left one registers 42V.

According to the schematic, there is nothing between the Red wire coming out of the Timer and the Operating Thermostat. I don't see how it could go from 121 to 70 or 83V. But I haven't taken the whole thing apart, so I have to ASSume that I'm missing something.

With a concern that power could be leaking into the frame... I decided to try and test the ground. I Ohmed out the little Green/Yellow ground wire that comes out of circuit board... then Ys off with one side going down below and the other that bonds to the back of the control panel frame. Between the control panel frame lug and the main, incoming ground wire, I get full continuity. Good.

Voltage: Between the main White and the main ground, I get zero volts. Good.

HOWEVER... between the back of the control panel/circuit board-ground and the White from the wall... I get 15V. Hmmmm. That doesn't seem right. So my guess is that the board has shorted... maybe.

BUT...

If I have continuity between all ground wires, why don't I also get 15V when I go between main ground and the White???

This is not my primary question, but it's interesting. My primary question is in regard to a diagnosis. Do you think it's the circuit board or...???

Of course the dryer sits unplugged when not under testing.

Your thoughts?
 

rickgburton

Appliance Tech - Moderator
Staff member
Joined
Jul 11, 2006
Messages
36,438
Location
Murray, Utah 84107, United States

Kendall

Premium Member
Joined
Oct 25, 2010
Messages
33
Location
Southern Oregon
I've apparently solved it. The Thermal Fuse Part number 3390719 has no continuity. I didn't eve know it was right next to the Operating Thermostat until I took the dryer apart.

Just for drill, I bypassed it and jumped the door switch. Lighted right up!

Too bad the system will no longer let me edit so I can add "Solved" to the subject line.

Thanks!
 

Jake

Appliance Tech - Admin
Staff member
Joined
Aug 24, 2004
Messages
105,289
Location
McMullen Valley, Arizona
I marked it FIXED for you.

Remember only by-pass the thermal fuse for testing, if you permanently by-pass it that is very dangerous and can lead to lint fires.

The main reason the thermal fuse blows is air flow restrictions in your exhaust hose that goes to the outside of your home, lint build-up over the years effects the air flow, also go outside and check your dryer vent, that can clog up too.

Jake
 

Kendall

Premium Member
Joined
Oct 25, 2010
Messages
33
Location
Southern Oregon
Thanks, Jake!

Yes. Definitely would not bypass a fuse for anything more than a quick test. Ever!

The outlet outside shows lint on the ground. It didn't used to do that. I'm hoping the work I did thoroughly cleaning the dryer, including the area around the lint screen, will help. The lint screen's gasket rolls over for a couple of inches or so. I'm wondering if that isn't the problem.

That said... now that we're back up and running, the lint screen seems to be capturing more than it has been.

I cleaned out the flex hose between dryer and wall and also the elbow in the wall. Now I will take a closer look at the outlet outside.

Thanks!
 

Jake

Appliance Tech - Admin
Staff member
Joined
Aug 24, 2004
Messages
105,289
Location
McMullen Valley, Arizona
Yes, check the outside vent while the dryer is on and running to make sure a good flow of air is coming out.

Jake
 

Kendall

Premium Member
Joined
Oct 25, 2010
Messages
33
Location
Southern Oregon
Yes, check the outside vent while the dryer is on and running to make sure a good flow of air is coming out.

Jake
Seems like there would be no substitute for experience judging that.

It's not a hurricane, but it definitely seems like it's flowing well.

Is there anything I should be looking for, flow-wise?
 

Jake

Appliance Tech - Admin
Staff member
Joined
Aug 24, 2004
Messages
105,289
Location
McMullen Valley, Arizona
Nope, thats it, should be fine then.

Jake
 
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