Help to identify the part

[mazieis]

Hi all and good time :hand_with_fingers_splayed:

can U help me please?

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

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

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

and next my find -->(TVS Diode) with part number (SMAJ15CA)

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

.i really need your help:eyes:

T H A N K  YOU So sO So MUCH:folded_hands::smiling_face_with_heart_eyes:

(mazie)

[AScha.3]

Hi,

What board is it ?

and which cpu ?

+

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

[mazieis]

Hello:hand_with_fingers_splayed:

thank U for asking?

1.its a mainboard of security car alarm system.

2-SAMSUNG --> S3F84NBXZZ-QT8B

3.shorted :frowning_face:

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

5.thank U again

[AScha.3 · Accepted solution]

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:

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.

[mazieis]

first of all, thank U for your time:folded_hands::smiling_face_with_smiling_eyes:

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:flushed_face:?

i hope it will be fixed:slightly_frowning_face:

anyway thank you SO MUCH for your guidance

have a nice day and night:hand_with_fingers_splayed::hand_with_fingers_splayed: