FIXED MVWB850YG1 2013 Maytag Top Load Washer - Unbalanced Load Error Even When Empty

[discgolf01]

Model Number

MVWB850YG1

Brand

Maytag

Age

6-10 years

Model Number: MVWB850YG1
Brand: Maytag


Hi Guys - appreciate any help you can provide.

Service history of the washer:
-Bought in Spring 2013
-Jan 2022 - Could not get through spin cycle without the Unbalanced Load error - I had the oil/grease on the floor, spin cycle sounded like a jet airplane, so I replaced the main bearings, seals, main shaft. At that time I also purchased a replacement set of aftermarket suspension rods figuring I would replace them at the same time even though there appeared to be nothing wrong with them when I pulled them out.
-Fixed worked great, no issues, until:

Issue:
-Wednesday this week, a load of laundry (normal size and quantity) could not get through the spin cycle without the Unbalanced Load error. Rearranged the load multiple times, still wouldn't get past about the 10 min left on the Normal cycle (medium spin) every time.
-Took some heavier items out, still wouldn't get past spin cycle without UL erroring out.
-Unplugged washer, tried to get through using rinse/spin cycle only setting on dial, still failed
-Took everything out and ran a spin cycle empty - still failed for Unbalanced Load error

What's happening during the spin cycle:
-It is not making the same loud high pitch whine it did when the main seals/bearings failed earlier this year. It's sounds as quiet as it usually does.
-Tub is not banging around the cabinet - to me, it looks like it should not be tripping a UL error as it, for the most part, stays centered in the unit, but does have some wobble to it.
-I replaced the suspension rods with Genuine OEM ones today - no change

Looking for any help advice I can get - my first thought is another bearing problem? But without the noise, does that make sense? Or a bad UL sensor (if that is even a thing?)

Thanks in advance!

 

[Jake]

Ok, I located the tech data sheet for your model: https://drive.google.com/file/d/12gd74sCAQ4Gq1LGO8tV9AZg0QlwHdvHH/view?usp=sharing

The STATOR MOTOR and Rotor Position Sensor(RPS) determine if its Unbalanced, You can do TEST #3 Motor Circuit to locate the problem on Page 4 of the tech data sheet.

Here's the Rotor Position Sensor(RPS) for your model:
WPW10178988 Rotor Position Sensor


Here's the motor stator assy:
WPW10419333 Motor Stator


Jake

 

[discgolf01]

Thanks a lot Jake! I didn't even know you could do this kind of diagnostic stuff with a washing machine.

So I was able to pass the Rotation Position Sensor test on Page 2 by manually rotating the drum.

While in Manual Diagnostic mode, I forced the washer into the 3 spin speeds: 23 rpm, 530 rpm, and 1000 rpm.

What is interesting is that at 530 rpm there was a visible wobble in the tub that would self correct about every 3 seconds then back to a wobble in another 3 seconds. This trend would repeat indefinitely.

But then when I put it to the 1000 rpm spin, the wobble was gone and the basket was very stable. My assumption is that the basket spin at 530 rpm should look identical as the 1000 rpm spin.

I am not certain how the RPS sensor is used to detect a UL error, but am wondering if there is an accelerometer in there that senses movement of the drum along with the actual position sensors for the rotor/stator.

So I am thinking it might be one of 2 things:

1. Something is off that causes a harmonic imbalance at 530 rpm, but not at 1000 rpm - not sure what this could be though? Some kind of counterbalance weight I am not aware of? Or something other than the 4 suspension rods that dampens vibrations in the drum?

2. The wobble at 530 rpm (which my assumption is the "Medium Spin" speed setting) is normal, but the RPS is not working correctly and saying it should be an error when it's not

I'm going to see if I can do the continuity/resistance test of the RPS tomorrow hopefully.

Any help is appreciated!

Update: I was under the unit and found the bolt that holds the rotor to the stator (and the main driveshaft?) significantly loose. I tightened it, added blue loctitite, and was able to get through a spin only cycle with no issues (oddly the basket still had the wobble noted above at 530rpm, but no UL error. Will run a normal load of laundry tomorrow to verify.

Thanks!

 

[Jake]

Update: I was under the unit and found the bolt that holds the rotor to the stator (and the main driveshaft?) significantly loose. I tightened it, added blue loctitite, and was able to get through a spin only cycle with no issues (oddly the basket still had the wobble noted above at 530rpm, but no UL error. Will run a normal load of laundry tomorrow to verify.

Sounds like you nailed the problem.

Good find!

Jake

 

[discgolf01]

Thanks Jake, and thanks again for the diagnostic procedure info - that will come in handy in the future.

I can confirm that it looks like the loose rotor/stator assembly bolt was the issue - we've done 2 more loads of laundry without an issue.

Here's my theory on what was happening based on limited knowledge, so I'll let others that understand washer design better than me correct me if needed: The bolt loosened the housing just enough that when the drum is spinning, the housing was vibrating at a frequency that either confused or caused the accelerometer in the RPS to register an unbalanced load when there actually wasn't one.

Hope this thread can help others in the future (and save them $60 from having to order new suspension rods when they are not needed).

 

[Jake]

Sounds good, thanks for the update and the added information.

Jake