Why won't the motor stop running when plugged in?

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Ninja Master Prep QB900B

the easy to use, easy to clean, 900 series interchangeable blender manufactured by Ninja. Released between 2009-2013

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breys2004 @breys2004

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Опубликовано: 10 янв 2016 г.

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Why won't the motor stop running when plugged in?

One day after normal use of blending, I pushed down the button to blend and then it never stopped running unless unlplugged.

I have disassembled the top motor portion and about a 1/4" diameter and 1/2" heigh spring fell out, but nothing else seemed obviously amiss.

Maybe I haven't found the right spot where the spring belongs and it had just worked loose, but I can't find a manual that shows where the spring should go.

I have tried putting the spring where the top piece contacts the bottom piece near the bottom side and near the top middle directly on the motor shaft. No luck.

Отвечено! Посмотреть ответ У меня та же проблема

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Pablo Limon @pelgv

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I've had this problem too. I disassembled the motor and I found the spring you talk about. That spring goes in side the long button that pushes the switch. It keeps the switch press down which is the safety switch that disallows the motor to start outside the bowl.

The reason of your problem of the motor being stuck on, might be the same as why mine stuck on for some time, and now it just does not work.

The switch assembly is a metal piece that pushes down in two copper spring wings. I found that one of those in my motor is completely eroded, gone.

As you can see, the copper is now all over the switch assembly (the black stuff, the red stuff is my food on the safety switch):

Here you can see a zoom in of the switch. Note the spring on one side, not on the other.

All the sparking of the on/off action has damaged the contact. If I press the metal piece that makes contact on both springs, I can get the metal piece to get stuck between the springs as shown here:

Getting the switch stuck might be a safety hazard...

I think the switch is beyond repair, it would be nice to know if I can get it somewhere...

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I fixed the same problem by spraying a little WD-40 on the switch and cleaning off all the black stuff. It works fine (for now). Whatever the black stuff was seems to be shorting out the switch.

13 июл 2020 г. из Michael Bett

i just fixed mine this way, just confirm it slides freely and it will work

28 июн 2022 г. из Jeffrey Binns

Same problem with the motor always running. I believe something pushed the safety up too far that it jammed the switch inside and popped the spring off, to boot. Freed up the internal switch and replaced the spring.

12 янв 2025 г. из Richard Steckler

In my case, the plunger switch was just stuck down, so always on. Pressing it a few times released it by cracking whatever caused it to be stuck—guessing it was food. Cleaned the part, put the everything back together and it works fine now.

17 янв 2025 г. из SB Art

(years later, I know) Thanks a lot for the great photos!

I took mine apart the same way, and was wondering about that one copper contact being much shorter than the other, thinking perhaps it had burned down, but I see yours is the same. I cleaned the copper motor rotor some, just using a pencil eraser, sprayed contact cleaner on those copper parts, used a bit of bike lube on the bearings, and somehow it does seem to be working for the time being.

Wish I could actually order a new switch from Ninja, but I guess they don't get down to those details.

10 мар 2025 г. из DiegoDude

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I fixed the same problem by spraying a little WD-40 on the switch and cleaning off all the black stuff. It works fine (for now). Whatever the black stuff was seems to be shorting out the switch. — Michael Bett
i just fixed mine this way, just confirm it slides freely and it will work — Jeffrey Binns
Same problem with the motor always running. I believe something pushed the safety up too far that it jammed the switch inside and popped the spring off, to boot. Freed up the internal switch and replaced the spring. — Richard Steckler
In my case, the plunger switch was just stuck down, so always on. Pressing it a few times released it by cracking whatever caused it to be stuck—guessing it was food. Cleaned the part, put the everything back together and it works fine now. — SB Art
(years later, I know) Thanks a lot for the great photos!

I took mine apart the same way, and was wondering about that one copper contact being much shorter than the other, thinking perhaps it had burned down, but I see yours is the same. I cleaned the copper motor rotor some, just using a pencil eraser, sprayed contact cleaner on those copper parts, used a bit of bike lube on the bearings, and somehow it does seem to be working for the time being.

Wish I could actually order a new switch from Ninja, but I guess they don't get down to those details. — DiegoDude