JBL Xtreme 2 Board Repair | Service tips needed

[HiddenBear]

Hello Fellow Forum Members

I'm currently fixing a JBL xtreme 2 main board/motherboard and I encountered few problems thats requiest knowlage that only the oldest electronic shamans have. The main problem is that the speaker dosen't turned on, so I checked at first the battery. Two of four 18650 cells where drained to 0V, the other two had 2.9V. I decited to left the two working cells and replace the drained one with some working one that I had. But after the swap I checked the speaker if it does turn on, but sadly it does not. Then I unpluged the battery from the speaker and checked the BMS, there was no voltage on the connectors. So I bypassed the BMS in reasumption that it was the main problem. Buuut after this tactical operation the speaker was still not powering on. So the logical conclusion was that the board itself was damaged. After geting inside I spotted after some time that one of the IC's is slightly roasted at one pin (the middel one). I found the schematic for the speaker from some bootleg sides and with the help of the post : https://www.eevblog.com/forum/repair/jbl-xtreme-2-chip-identification/msg3972923/#msg3972923 I found out that the chip name is SY8201. And after studing the JBL bootleg service manual I found out that the chip is responsible for powering the whole 3.3V logic. So it make sens that the speaker woundn't turn on if he didn't get any power. Sooo to make sure which side is damaged, the power side or the controler side, I check with my BM252S the voltage. Sadly I didn't have any precision multimeter probes and wity my fat ones I made a short cut on the L48 coil (funny me xD).

Long story short  . If the main 3.3V DC-DC regulator is damaged should I search for some other sighs of damage? Or can I replace the two elements and savely start the speaker? The L48 coil description is 600R 100MHz, I found that it's a coil that at this frequency has 600 ohms (Source : https://electronics.stackexchange.com/questions/384738/what-does-600r100m-mean-from-rda5807m-datasheet). The next question is if I need to replace it with exact the same one? I know, idealy I should do it. But then there is the last question. What amp value should I pick? Because there are two options. I found a 0.45A and 0.8A version, description : [ impedance 100MHz = 600ohm; Resistance = 0,25ohm;- cal = 0603; mm = 1608 Producent = MURATA] . The SY8201 I ordered already from Aliexpress (the only place I could find thoes). But now I need to order the coil or find out a replacement for it. Technicly I could solder out a element from a other board, alas I don't have a element identifier device.

(Disclamer english is not my main language of choice, in case on any grammar mistakes sorri >_< )

Below I drop the current state of the damaged region, schematic of the damaged region as well the whole service manual if someone coundn' t find it at the weeb.

[m k]

Coil is for noise.
Burned component means high power, so least guarantee against later faults.

You can start feeding it with current limited external 3.3V source.