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Identify component L2

davenn

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Sep 5, 2009
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I have found a short circuit on the component L2 but I don't know what it is? it looks like a diode..

Thankyou @kellys_eye , finally a correct answer is given

Yes, it a 1/2 turn ferrite bead, and as Kelly-eye is used for suppression .... generally noise /RF suppression on a data line or a power rail


The top (Black) has come from L2 and reads as a resistor, and the bottom which looks like a resistor is the one that reads as an inductor?

the green bodied part is also an inductor but it's going to be a multi-turn coil

Brown Green Red
1 5 00

not sure if that is going to be 15uH or 150uH ??

.
cheers
Dave
 

BillyWhiz

May 22, 2023
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Hi Kellys Eye,

Thanks for responding, it was just that I was checking through a PCB and found it was reading short that I suspected it to be faulty.
 

Harald Kapp

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found it was reading short that I suspected it to be faulty.
Not every short is a fault. Believe it or not there are actually 0 Ω "resistors". used e.g. as links to enable (or disable) certain circuit functions.
 

Delta Prime

Jul 29, 2020
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Future reference this is the schematic symbol and or designator on a PCB for ferrite bead.
1684781100515.png
 

kellys_eye

Jun 25, 2010
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Hi Kellys Eye,

Thanks for responding, it was just that I was checking through a PCB and found it was reading short that I suspected it to be faulty.
I understand what you came across and why your thoughts went in that direction but it also illustrates the old adage - "if it ain't broke, don't fix it"....:)
 

Delta Prime

Jul 29, 2020
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Yin and yang.
I disagree .if it's not broke all that means is, it does not have enough features. :cool:
 

BillyWhiz

May 22, 2023
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Hi Guys,
I am trying to fault find a Microwave PCB so i am testing components to see which are faulty...:rolleyes:
 

Delta Prime

Jul 29, 2020
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Hi Guys,
I am trying to fault find a Microwave PCB so i am testing components to see which are faulty...:rolleyes:

I was just teasing it out of you. (pun intended).
Make,model,of microwave please.
I will see if I can't grab a schematic for you.
 
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Delta Prime

Jul 29, 2020
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Now you're teasing me,that info would be nice, while I'm looking for the schematic can take another photo thank you
photo_1684806923295.png
 

BillyWhiz

May 22, 2023
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The Microwave stopped working as nothing happened when we pressed any of the buttons. I opened it and found that most of the buttons needed replacing. After that when pressing start the magnetron did not operate, I checked all the door switches and they where fine, it appeared that the board was not supplying voltage to the magnetron. I found the EE16transformer not working, and I am awaiting the new part arriving. So i decided to check through the rest of the board for other faults.
 

Delta Prime

Jul 29, 2020
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Haven't forgot about you.No schemo. You're good with the soldering iron so. Be careful with that magnetron. work gloves while handling it. And a face mask. And look up the dangers of handling magnetrons. We'll go to the power supply if you can take photos we'll have to work off of that & a multimeter. And please do not jump the gun and turn it on.
Just follow the power cord into the microwave and take photos. thank you :)
 

BillyWhiz

May 22, 2023
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Ok first picture is the incoming supply.
 

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kellys_eye

Jun 25, 2010
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The Microwave stopped working as nothing happened when we pressed any of the buttons.
Most microwaves that have 'digital' circuits (keypad operation, not the simpler rotating mechanical timer versions) have a defined supply for the electronics (5V) that frequently comes via a capacitor dropper/rectifier/regulator (sometime an SMPS) system.

We would need to see the actual board that has all the electronics on it.

The rest of the machine is basically relays, switches and the transformer/magnetron. This side of it, assuming the magnetron isn't knackered, is usually unbreakable but the power supply to the electronics suffers from the same 'blown capacitor' issues that many such power supplies do these days.

Show us the control board.
 

BillyWhiz

May 22, 2023
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Okay here is the circuit board with the small EE16 transformer missing as I took it out to test it. It shows faulty on the meter!
 

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kellys_eye

Jun 25, 2010
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It shows faulty on the meter!
In what way is it showing 'faulty'?

In these circumstances it is usually the controller IC (IC1) that has failed. It 'might' have taken out the primary of the transformer but that's a very, very rare occurence.
 
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