find faulty compnent on ATX power supply

[pharaon]

it's ATX power supply i'm working on
the issue is in 5V output, it drop to 3V when i connect it to 12V pc fan, and the fan keep kicking without spin
i hear fry sound from this side of main transformer but can't detect exactly which component making the sound or responsible for not delivering enough current to 5V line output

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[davenn]

it's ATX power supply i'm working on

Honestly, they are just not worth the time and frustration trying to repair them

 

[pharaon]

Honestly, they are just not worth the time and frustration trying to repair them

i'm doing it for learning purposes

 

[Bluejets]

i'm doing it for learning purposes

Lesson 1.......it's not worth the time and frustration trying to repair them.
There are many avenues to learn electronics and the overall best ( as it always was) is to study the theory.
Then one can apply newfound knowledge correctly.

Starting point possibility...... https://www.power-supplies.com.au/files/mean-well-user-technical-manual.pdf

 

[pharaon]

in the below image to the right is the connector of cooling fan, it doesn't start and voltage at connectors drop from 12 to 3 when the fan is connected, i back traced it and removed smd NPN transistor that is shorted and this is it's datasheet
http://elektrikaetoprosto.ru/ebc849c.html
i replaced it with STC945 NPN transistor since i couldn't find smd one but the same issue still exist.
also ther's those two gray and yellow wires connected to the heat sink beside cooling fan tracks .
what could be the reason for this issue

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