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Help on identifying this resistor or inductor

Kcrypto

Jul 7, 2018
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Hello All, I have a burnt out component on my pcb board. Its square in shape with coils inside, so i think its a shielded SMD inductor.
There are numbers on the component:

1R5
1784

Any one have a clue the value?

Help greatly appreciated :)

Ken.
 

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(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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That's an inductor. Note the designation on the board of L5.

It could be 1.5μH
 

kellys_eye

Jun 25, 2010
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Could be part of a buck or boost circuit and such inductors may burn out because the switching device has gone short - they rarely 'go' on their own.
Worth checking the adjacent circuit(ry).
 

KJ6EAD

Aug 13, 2011
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I'll venture a guess that the one pictured is another of same value as the failed one but Kcrypto will have to confirm or deny.

By the way, the 'B' in the acronym 'PCB' represents the word 'board' making the term "PCB board" redundant.

P.S. Should the decimal place holder for an inductor designation be 'L' instead of 'R' such as 1L5 instead of 1R5?
 

Kcrypto

Jul 7, 2018
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Thanks for the reply guys, much appreciated really.

I have three boards. One component on one board is good (its working) and the other 2 boards are dead. I've included a pic of the 'burnt out' component and the opposite side. I can find 1R5 inductors (Inductance 1.5 μH), but theres many variations such as the Amps and Resistance (Ohms).

I'm no expert in electronics, so no idea in how to test other parts of the circuitry.
 

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davenn

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I've included a pic of the 'burnt out' component

so the burnt out component may not be the inductor ?
But the upper right component under the finned heatsink has let out the smoke

So you need to find out what the heatsink is on top of
 

Kcrypto

Jul 7, 2018
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so the burnt out component may not be the inductor ?
But the upper right component under the finned heatsink has let out the smoke

So you need to find out what the heatsink is on top of

The board visually looks good except for that inductor which has bulged and burnt.
What seems to be residual of smoke from the heatsink is in fact dust from a powerful fan which sits beside the board blowing in.
 

davenn

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What seems to be residual of smoke from the heatsink is in fact dust from a powerful fan which sits beside the board blowing in.

OK :)


I can find 1R5 inductors (Inductance 1.5 μH), but theres many variations such as the Amps and Resistance (Ohms).

A little difficult without knowing what current is usually flowing through that part of the circuit

The significant thing is, it's a 99.999999% probability that those inductors just die on their own, it pretty much doesn't happen
This means that something to the right of it failed and is drawing excess current

what are the components I have arrowed ... list what is written on them

there seems to be a mirror of components to the left and right of a centre line of that larger central chip I have labelled A

I'm picking that the 2 squarish chips immediately to the right of the left inductor and to the left of the right inductor are probably some sort of switching regulator

one or more may be cooked .... do you have SMD IC removal and replacement skills ? .... you are going to need them

upload_2018-7-9_12-43-46.png



Dave
 

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Kcrypto

Jul 7, 2018
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Thanks Dave for your help.

The Chip labelled A is dsPIC33EP16
2 Chips either side is 3110A PSGN
4 Outer chips are NIKOS PKCH2BB GUE6TD01

The board consumes ~37A @ 12v DC

As for SMD removal....I have a soldering iron haha thats a start.
I might try removing one of the good 1R5 chips and placing it onto the burnt out boards to see if it works. I really dont fancy removing those chips mentioned :( If it does, its a matter of finding the value for a replacment 1R5.

Thanks again for the help :D
 

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(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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The one labelled dsPIC33EP16 is a microcontroller that is programmed. If this is damaged then you probably can't fix the board.
 

Kcrypto

Jul 7, 2018
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Hi All.

Managed to make good of one board of the two. Took a good 1R5 inductor and replaced the burnt out one. all is working now. Seems like the inductor is the only faulty part. Now have a board with two missing 1R5 inductors. :(

Thanks for everyone who helped. Great forum too. Keep it up!!
 

davenn

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Hi All.

Managed to make good of one board of the two. Took a good 1R5 inductor and replaced the burnt out one. all is working now. Seems like the inductor is the only faulty part. Now have a board with two missing 1R5 inductors. :(

Thanks for everyone who helped. Great forum too. Keep it up!!


Awesome .... thanks for reporting back :)
 
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