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Whrlp Master Tech
Whrlp Master Tech, Whirlpool Master Technician
Category: Appliance
Satisfied Customers: 10565
Experience:  30 years Appliance Field 15 yr with Whirlpool Corp. 9 yrs Whirlpool Technical Assistance Line
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I have a psb1201nss01 advantium oven which stopped working.

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I have a psb1201nss01 advantium oven which stopped working. I replaced the thermal fuse next to the megatron and it worked one time and blew the fuse again. I am not sure if I attached the two wires correctly. Would that make a difference? If not what would be the next step?

Hello from Just Answer and the Appliance Category
I`m sorry to hear that your having issues!
My name is Woody.
I will be glad to assist you today.
I have been servicing ALL Major Brands of Appliances for 37 Years, I own my own Appliance repair Company
And I teach appliance repair at a local Community College.
I have over 100,000 plus in home repairs and over 80,000 internet repairs under my belt.
You will be paying me for my ANSWER to your Appliance Question,, Not for the repair of your appliance hence the name of this site Just Answer.
I will do my best to take the information that you provide to me and make a Diagnosis for you to be able to repair your own Appliance.

No the placement of the two wires on the Magnetron thermostat would not make a difference.

But if it was bad when you replaced it ,did you check to see if the Magnetron cooling fan is running?

Customer: replied 1 month ago.
No I did not check the Mag cooling fan, not even sure where it is. Both the old and new fuse test as "OL". If I try another fuse it may blow also. Is there a way to test the cooling fan? or what do you suggest as the next step. We do believe the microwave is getting overheated.

The cooling fan on this model should be running anytime the microwave is in use.

And if the fan is not running you can test it to see if it is getting voltage or not.

And yes if the magnetron thermostat is opening then the unit will be getting too hot

Customer: replied 1 month ago.
Is the fan you are referring to the one that has two cages on it?
If the thermal fuse is blown will this fan receive voltage?

yes that is the cooling fan.

and if the magnetron thermal opens is normally will not effect the cooling fan operation .

Customer: replied 1 month ago.
I noticed there is another thermal switch on top of the heater and the terminal on the black wire is burnt pretty good so most likely that one is blown also. With this update do I still need to pursue checking voltage at the cooling fan,
If so, how do I gain access to the terminals on the fan motor?
Customer: replied 1 month ago.
Update - got the top cover off - the voltage is about 11 at the fan. The terminal on the heater thermal fuse was fused together but I got it apart OK. The terminal on the fuse is lose and gives a 0 reading at times then OL at others so looks like it needs to be replaced.

Ok That is a 120 volt fan motor and it should come on as soon as you turn the microwave on.

It should have operated that way from day one .

Did it not?

Customer: replied 1 month ago.
The fan is not coming on now and I do not know how it operated in the past. I had replaced the microwave thermal fuse once but it blew after one use and at that time I did not know to check the fan.. So at this time I have blown microwave fuse and a damaged heater fuse still installed. So the display is not working and I do not know how to turn the microwave on. I have not replaced the fuses for fear they will blow again. Do I need to disconnect the fan and attach a power source to it to see if it works or do I need to sacrifice a fuse to see if the fan works or do you suggest otherwise?

I would direct feed voltage to the fan to see if it is working .

And as a service company we use a reset-able type fuse for testing so you do not keep replacing good parts.

Customer: replied 1 month ago.
When using direct feed for testing the fan will polarity matter?

no it is a A/C voltage fan not D/C voltage!

Customer: replied 1 month ago.
Tried the direct feed - fan works
voltage at fan with blown fuse .006
voltage at fan with new fuse and microwave on 115-119
I only left the microwave on about 10 seconds and fuse did not blow so far.
Customer: replied 1 month ago.
The fan did work with the new fuse and the microwave on

Ok so we now know the fan is working .

What is the part number of the thermal that you replaced that was on the magnetron ?

I`m showing it is a part number of Thermostat WB21X10148

Customer: replied 1 month ago.
that is the number I bought.

Ok that is the correct Magnetron thermostat.

It is possible that the new one was bad , did you ohm it out before you installed it by chance?

Customer: replied 1 month ago.
Well I have gotten confused between the original, the second and third one but I think I did and only would have used if it tested at 0. The second one lasted for one thirty second express cycle and then measured OL so it seems it was good to start with but I guess it could have been weak. The third one is install now but only used it for about 10 seconds and still works.

ok All I could suggest is to run the unit and see if this newest one last and make sure that the control board is also in fact powering the cooling fan the entire time the unit is operating .

Oh and of course make sure your operating the unit with the cover back in place ,if not you will not have proper air flow!

Customer: replied 1 month ago.
I was able to run 3 or 4 express cycles and fuse did not blow and fan stayed on when the microwave was on. The bad news is there is a loud hum when the unit is plugged in and after using the microwave for about 15 - 20 seconds there is a vibration sound. The megatron is getting very hot. All covers are installed except the small one next to the fan. I never noticed any of this before. The inside of the microwave seems very hot. A cup of water rose to 110 degrees in 30 seconds.
Customer: replied 1 month ago.
Thinking back my wife said she did hear a noise when the first fuse blew.

well we can say it is heating but you still have or it seems you have a over heating issue on the magnetron.

So you have to be looking at some type of an air flow problem.

Check the damper to make sure it is opening and closing , that would restrict air flow from what I can see on the parts break down .

Customer: replied 1 month ago.
Would the damper be number 5007 on the diagram?

yes that is the motor driven damper door!

Customer: replied 1 month ago.
As soon as I plug in the unit the damper turns and then turns back, Nothing occurs when the microwave is turned on. Hum/vibration occurs as soon as unit is plugged in and only stops when the door is opened.

ok this is the first I`m hearing about a hum as soon as you plug it in .

Can you tell where this hum is coming from?

Customer: replied 1 month ago.
I mentioned the hum on September 13.
I checked the damper with the rear cover off. I am afraid to run it with the top cover off for fear the fuse will blow. By feel it seems the hum is coming from the megatron or very close. The whole top cover vibrates but more near the megatron. If I remove the top cover right after using it the megatron is very hot.

oh yes you did! mention the hum!!

ok the magnetron should not be loud and if it is loud and the thermal blew you may have a magnetron that is going bad.

Here is the magnetron part info if you need it .


If you have any questions just reply back to me .

Customer: replied 1 month ago.
Changed the mag - no difference. Hums until you open the door or unplug it.
I removed the top cover to try and tell what was humming. I did not even set the clock but I noticed the inside fogging up. I have a cup of water inside and it became hot. It heated the water without the microwave or anything else being turned on. Does not sound normal to me. I stopped looking for the hum at that point but can investigate further if still needed.
Customer: replied 1 month ago.
Just checking to verify you are still working with me. Thanks

I just now see your reply from The 16 th and was on line all day yesterday!! and never got it .

If the unit is humming and it was heating with out the unit even being programmed it sounds as if you have a replay on the control board that is bad (stuck closed) allowing power to the magnetron ,and that would cause the thermal fuse to open if the fan was not running but the magnetron was producing heat.

That would mean you need to replace the main control board .

Let me pull the info back up and give you that info .

repair clinic shows it out of stock until oct 3-oct16

So here is a link for Sears they show it in stock.

Customer: replied 1 month ago.
My wife has be
Customer: replied 1 month ago.
My wif
Customer: replied 1 month ago.
One more time. My wife has been trying to convince me the sh
Customer: replied 1 month ago.
She was not using the unit when the first fuse blew and I was not convinced. She was only using the oven below. Now it makes more sense. Any tips on replacing the board. I replaced one in the fridge recently.

the unit has to be remove from the cabinets and the top removed ,the relay board is right behind the control panel /

The relay board is #1653

I see you have not rated me as of yet!
Even after you rate me if you have a question just reply back to me,
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Customer: replied 29 days ago.
The relay board did the trick

Great !!

Glad to assist you anytime !!

Tell the wife she ((OWES)) you!!

Thank you!

If you need me again for any other issues you can request me Whrlp Master Tech.