Author Topic: Part identification help need pls.  (Read 276 times)

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Offline Chriss

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Part identification help need pls.
« on: April 15, 2019, 07:19:23 pm »
Hi!
I have to identify a part on a graphics card.
Check the picture for the part I search for.

Is it a MOSFET or a diode?
I found some sources on the internet they talk about like if it is a mosfet but when I check it with dmm it reakt like a diode.

There are also several same parts on the pcb and I compared the readings with each other but they are the same.
It is impossible does all the same parts are bad on the pcb.

If I check for continuity between the middle pin and the right pin (D and S) it react as a diode.
But no reaction when I measure between all the pins and the left pin.

Any idea what part this could be?

Thanks.
 

Offline kosomsk

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Re: Part identification help need pls.
« Reply #1 on: April 15, 2019, 08:52:23 pm »
« Last Edit: April 15, 2019, 08:54:55 pm by kosomsk »
 

Offline testpoint1

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Re: Part identification help need pls.
« Reply #2 on: April 15, 2019, 09:12:13 pm »
Hi!
I have to identify a part on a graphics card.
Check the picture for the part I search for.

Is it a MOSFET or a diode?
I found some sources on the internet they talk about like if it is a mosfet but when I check it with dmm it reakt like a diode.

There are also several same parts on the pcb and I compared the readings with each other but they are the same.
It is impossible does all the same parts are bad on the pcb.

If I check for continuity between the middle pin and the right pin (D and S) it react as a diode.
But no reaction when I measure between all the pins and the left pin.

Any idea what part this could be?

Thanks.

T14N03, MOS FET, TO-252
 

Offline Chriss

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Re: Part identification help need pls.
« Reply #3 on: April 16, 2019, 06:22:10 am »
testpoint1:
Thanks for the info.
Do you maybe have a datasheet for it?

The datasheet from this site http://www.onsemi.com/pub/Collateral/NTD14N03R-D.PDF is incorrect.

Based of the pinout on that link the middle pin is the D and the right pin is the S.
Between these two pins I can read a diode type of reading. If I put the positive probe of my dmm on the D
and the negative probe to the S I got a reading like 1998mV. If I interchange the probes I got a reading of 600mV.
And I can't brake the conductive state of that two pins as it should be done on a regular MOSFET.

I know, there is a protective diode between the S and D but why can I not make conductiv the D and S and after that I should could break the conductive state between the S and D.
I mean, I should power on and off the MOSFET with my dmm.

I also don't assume does 5 or 6 of these MOSFETS are actually all killed on the graphics card, but they all
react the same way.
« Last Edit: April 16, 2019, 06:24:49 am by Chriss »
 

Offline bob91343

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Re: Part identification help need pls.
« Reply #4 on: April 18, 2019, 02:21:57 am »
For this kind of identity problem, I would use one of those cheap Chinese 'magic' devices that cost around $30 complete and are capable of identifying many kinds of parts.  They were invented by Europeans but China has produced them at very affordable prices.  Google MEGA328 I think; get them from ebay.

They measure nearly any part, R, C, L, diode, transistor (many types) and so on.  They also identify lead configuration.  I have found mine nearly invaluable.  Not that the result is always accurate but for what it does I don't mind.  Once I establish identity I can use my other test gear for better readings.
 
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Offline Chriss

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Re: Part identification help need pls.
« Reply #5 on: April 18, 2019, 05:27:21 am »
Yea!
I ordered one of these tester from aliexpress some days ago... anyway thanks for the suggestion.  :)
 


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