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FIXED Bravos MVWB750WQ0 does not spin except in manual mode with error code F72

quortrco

Premium Member
Joined
Feb 13, 2018
Messages
3
Location
Fort Worth, TX
Model Number
MVWB750WQ0
Brand
Maytag
Age
6-10 years
After about 8 years my Bravos started making a loud noise while spinning like an airplane taking off. To fix this I repaired the tub seal and bearing. After the repair I am getting an F72 error. I went through all of the manual tests and it fills, drains, spins, etc fine when testing in manual mode. When going through diagnostic tests it hangs on C8. Water drains in that stage, but it never spins, so it can't tell that the basket is engaged. I'm not sure what it means to disengage and engage, but it gets through C1 fine, where the washer fills until the "basket floats" and moves on until C8, so it seems like it's something during C8 and related to the engagement process. Any ideas on how to fix this? :confused:

My thinking is that the basket is engaged, but the washer doesn't know it, so it could be a sensor or control board issue. However, since I don't really understand what's supposed to be happening when the basket "floats" or disengages and then later engages it might still be something getting in the way of that process.

By the way, when going through the manual spin test it spins "quietly" now, so the repair DID fix our original issue.:encouragement: When trying to run a "rinse and spin" or "drain and spin" cycle, during the spin portion, it just rotates back and forth maybe 1/3 rotation each way in a jerky fashion, but never actually spins.:mad:
 
Last edited:

Jake

Appliance Tech - Admin
Staff member
Joined
Aug 24, 2004
Messages
131,557
Location
Redmond, Oregon
This problem ONLY started after you replaced the bearing? Wait, you said you repaired the bearing? Not replaced it?

Ok, I located the tech data sheet for your model:

F72=Basket Re-engagement Failure

F then 72 flashes when the basket check routine fails to determine if the basket is re-engaged after being disengaged.
--->Is the basket floating? if yes, pump out water. See Long Drain (Ld) procedure.
--->Does basket turn freely? If not, determine cause of friction.

C8=Drain to basket engaged plus timed drain for 10 seconds.
--->If water is not draining, go to Manual: Pumps test, page 2.
--->If basket does not engage, determine cause of friction

How fast is the water draining? Pull your drain hose up and watch it drain, should be a very strong stream out.

If so, then you have something causing friction if the basket is not engaging in C8.

You'd need to go over everything you did when you replaced the bearing, And I hope you replaced it, and not repaired it, because there is no way to repair the bearing, it must be replaced.:)

Here's the bearing kit(Video Included):
W10435302 Bearing and Tub Seal Kit


Here's the bearing driver installation tool:
W10447783 Bearing Installation Tool


Jake
 

quortrco

Premium Member
Joined
Feb 13, 2018
Messages
3
Location
Fort Worth, TX
Thank you for the reply. I did replace the parts. I used repair in the general sense of fixing the problem. Sorry for the confusion.

It drains fast and strong. No problem there.

The part about friction and engagement is what's got me confused. What does it mean to disengage and engage and float? The reason I ask is that I can put it in spin test mode and cycle through all the speeds and it does it fine. So to me that means it actually is engaged. Does that make sense?

What sensor tells it the basket is engaged or disengaged? Maybe that's where the problem is? Maybe it got damaged during the repair?

What friction should I be looking for? Something keeping it from spinning freely on the shaft or is there some up and down movement involved in the disengage/engage process?

When it asks about floating, is that just a question about the water level? The C1 process implies that when water is added the basket floats and disengages, so does that mean it raises up somehow when it floats in the water and that vertical movement disengages it? Disengages from what?

I guess it's appropriate that my head is spinning. This is a washing machine after all!
 

Jake

Appliance Tech - Admin
Staff member
Joined
Aug 24, 2004
Messages
131,557
Location
Redmond, Oregon
What sensor tells it the basket is engaged or disengaged?
The drive motor is an electronically commutated direct drive 3-phase brushless DC design that moves the impeller/agitator and spin basket without the use of a transmission.

The motor is comprised of a stator that is bolted to the base of the washer tub and a rotor that is attached to the drive shaft. The motor direction and speed is controlled by the machine/motor controller, and is monitored by a rotor position sensor, (RPS), located on the stator.

When it asks about floating, is that just a question about the water level? The C1 process implies that when water is added the basket floats and disengages, so does that mean it raises up somehow when it floats in the water and that vertical movement disengages it? Disengages from what?

As the tub fills with water, the basket begins to float and to rise. The splined hub components now separate, and allow the basket to move independently of the drive shaft, thus When the Water Level Rises & Basket Floats then the Outer Basket Hub Disengages.

When the tub drains, the basket drops back to it’s original position, and the hub components re-engage, connecting the basket to the shaft, and permitting the basket to spin.

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


So, I'd do --->TEST#3 Motor Circuit, in the tech data sheet I posted for you above<--- That will allow you to test all the motor components including the rotor position sensor, (RPS), located on the stator.

Jake
 

quortrco

Premium Member
Joined
Feb 13, 2018
Messages
3
Location
Fort Worth, TX
I didn't end up doing TEST #3 Motor Circuit test, but I did get it working again.

The basket was floating and disengaging when enough water was in the outer tub and then re-engaging when water was pumped out, so I figured the fault had to be somewhere else. F72 says if the tub is NOT floating, look for sources of friction. After reading more online and watching more videos on the bearing and seal replacement I noticed I had installed the tub seal upside down.:stupid: I took the rotor and stator off and tried to rotate the shaft by hand and it was pretty tight and hard to spin. So I ordered another seal (just the seal, not the whole kit) and replaced it again (the correct way, with the spring side facing down) and now it works!:applause:

I'm not 100% sure that the upside down seal was the problem, because the shaft still seems kind of tight and hard to spin, but it's working so I'm satisfied. It sure spins a lot easier without the seal, but of course you need the seal to keep water out. FYI, I had to use a sledgehammer to get the shaft out (both during the original replacement after 8 years of use and during the 2nd replacement after 1 week of troubleshooting), but the seal that was in upside down appeared undamaged after being hammered out with the shaft. It had only been in there about a week and had seen almost no water or use. I used the brand new one since I already had it, but I might not have had to buy the 2nd seal (for those that might end up in this same situation).

I'll keep my fingers crossed that this fix sticks. So far so good...
 

Jake

Appliance Tech - Admin
Staff member
Joined
Aug 24, 2004
Messages
131,557
Location
Redmond, Oregon
Excellent, good find on that tub seal that was upside down.

Don't feel bad, I've done things like that before, and realized it when I was testing my own repair at a customers has many moons ago.:)

Glad that was all it was.:)

Jake
 
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