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Old 09-16-2021, 08:41 AM   #1
magneh
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Default Harman Kardon Aura Studio 2 speaker - no power - how to identify IC?

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!
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Old 09-16-2021, 07:24 PM   #2
R_J
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Default Re: Harman Kardon Aura Studio 2 speaker - no power - how to identify IC?

It is a EUTECH EUP3484 buck regulator
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Old 09-17-2021, 01:49 AM   #3
magneh
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Default Re: Harman Kardon Aura Studio 2 speaker - no power - how to identify IC?

Quote:
Originally Posted by R_J View Post
It is a EUTECH EUP3484 buck regulator
Thanks R_J!

Will replace it and try to fix the speaker
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Old 09-18-2021, 05:44 AM   #4
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Default Re: Harman Kardon Aura Studio 2 speaker - no power - how to identify IC?

Dont forget to check the capacitors around as well
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Old 10-07-2021, 09:00 AM   #5
magneh
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Default Re: Harman Kardon Aura Studio 2 speaker - no power - how to identify IC?

Quote:
Originally Posted by DjKrish View Post
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!
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Old 10-07-2021, 10:59 AM   #6
stj
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Default Re: Harman Kardon Aura Studio 2 speaker - no power - how to identify IC?

http://www.sznotec.com/PDF/EUP3482A.pdf
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Old 10-08-2021, 10:00 AM   #7
R_J
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Default Re: Harman Kardon Aura Studio 2 speaker - no power - how to identify IC?

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.

Last edited by R_J; 10-08-2021 at 10:06 AM..
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