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Help to identify the part

mazieis
Associate II

Hi all and good time

can U help me please?

i'm confused about this part with the (UM smd code),


UM2.jpgIMG_20240427_091348.jpg

i searched a lot on google and but i found only 2 parts with this smd code... (zener diode and tvs diode) !!

my first find --> zener diode Bzx84j-C5V6 SOD-323

bzx84j-c5v6.png

and next my find -->(TVS Diode) with part number (SMAJ15CA)Screenshot 2024-04-27 at 11-17-48 Bourns® Chip Diodes - Bourns-SMAJ15CA-datasheet.pdf.png

i got crazy.. which one should i choose????

.i really need your help

T H A N K  YOU So sO So MUCH

(mazie)

 

1 ACCEPTED SOLUTION

Accepted Solutions

Hi,

still more to ask :

- how you found the "shorted" diode ?

- what signal/condition caused the failure ?

- are you sure, the cpu still ok ?

 

+

the cpu seems 5V type, s3f84nb , qfp64:

AScha3_0-1714218920896.png

So pin4 (the diode goes here and to pin 9 , VDD) is a protected input : guessing -> a 5V6 zener makes more sense here, than a 15V protector.

If you feel a post has answered your question, please click "Accept as Solution".

View solution in original post

4 REPLIES 4
AScha.3
Chief II

Hi,

What board is it ?

and which cpu ?

+

Why you ask ? (It looks good...not working - or ??)

If you feel a post has answered your question, please click "Accept as Solution".

Hello

thank U for asking?

1.its a mainboard of security car alarm system.

IMG_20240427_141436.jpgIMG_20240427_141633.jpg

2-SAMSUNG --> S3F84NBXZZ-QT8B

IMG_20240427_133810.jpg

3.shorted

4.please tell me which one should i choose??

5.thank U again

 

Hi,

still more to ask :

- how you found the "shorted" diode ?

- what signal/condition caused the failure ?

- are you sure, the cpu still ok ?

 

+

the cpu seems 5V type, s3f84nb , qfp64:

AScha3_0-1714218920896.png

So pin4 (the diode goes here and to pin 9 , VDD) is a protected input : guessing -> a 5V6 zener makes more sense here, than a 15V protector.

If you feel a post has answered your question, please click "Accept as Solution".

first of all, thank U for your time

then i have to say this ; i tested this diode with a multimeter both inside the circuit and outside the circuit, and in both cases the multimete showed zero volts. idk why?

i hope it will be fixed

anyway thank you SO MUCH for your guidance

have a nice day and night