Harman Kardon Aura Studio 2 speaker - no power - how to identify IC?

[magneh]

Hi

Long story short, Harman Kardon Aura Studio 2 speaker, no power.

Disassembled, found burned IC, maybe the 5V regulator? not sure
No schematics

IC marking: 225S2 (see pic)

Board ref: 40-KS320U-PSK2G

Thanks for any help!

[R_J]

It is a EUTECH EUP3484 buck regulator

[magneh]

Originally Posted by R_J

It is a EUTECH EUP3484 buck regulator

Thanks R_J!

Will replace it and try to fix the speaker

[DjKrish]

Dont forget to check the capacitors around as well

[magneh]

Originally Posted by DjKrish

Dont forget to check the capacitors around as well

So I got the IC to replace, it was indeed the 5V regulator IC.

All caps measured OK, I checked the values of each pin before and after replacement and values were all OK.

So Ive connected power to it, but still no joy, unit does not power up.

Now I have 5V on the left coil, but the smaller one on the right, which I think is the 3.3V , has 0V.
The IC with ref. 336K2 has 19V at the 2nd pin, but 0V at all other pins.
Pin 3 is output as its connected to the coil.

Googled "336K2" did not give me much result, how can I find the datasheet for this one also?
No shorts found on this IC either, only pin4 which is ground.
Any hints?

Thanks!

[stj]

http://www.sznotec.com/PDF/EUP3482A.pdf

[R_J]

On that ic, Pin2 is the Vin, but you will not have any output if the EN (enable) pin is 0 volts, I suspect the regulator is not being told to turn on. If the 5v regulator went bad, it may have damaged other components it supplies, If it supplies standby for the main microprocessor, it may have been damaged? Try and trace that 5v line and see what it supplies, it may be something like a open 0Ω resistor that feeds a critical ic.