JBL Xtreme 2 Board Repair | Service tips needed  - Page 1
Forum section: electronics / repair

author: HiddenBear
author_rank: Newbie
timestamp: March 15, 2024, 03:35:26 pm
content: Hello Fellow Forum MembersI'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/#msg3972923I 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.

author: m k
author_rank: Super Contributor
timestamp: March 23, 2024, 02:01:04 pm
content: 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.

author: HiddenBear
author_rank: Newbie
timestamp: May 21, 2024, 05:30:02 pm
content: Got a bit busy lately and coundn't give a proper respond, sorry for that. Sadly I don't have a trustworthy power supply that I could use.So I replaced the IC with a new one and solderd a new L48 coil. Checked for continuity and everything was connected right without any unwanted shorts. Sadly it didn't work.But in the meantime at my local technical university I got to my hands a termocamera, so I made few mesurments that the time allowed my. Photos below. We can see that some of the elements are extremly hot in pomperation to others. And I don't know if it should be like that or just swap some elements. Looks like a shortcut for me but wanna get sure.

author: perieanuo
author_rank: Frequent Contributor
timestamp: May 22, 2024, 07:50:44 am
content: hi, a 'short' this obvious is easily found with resistance/diode measurements. even without plugging a supply on that rail.if you're lucky is just a cap, or other component

author: m k
author_rank: Super Contributor
timestamp: May 22, 2024, 08:17:09 am
content: It seems to go through R222 and R225 but pass R258 and go to Q2.Shouldn't be a normal thing.Actual temp is not visible but difference is too much for the area of that size.

author: girander
author_rank: Newbie
timestamp: October 23, 2024, 07:41:25 pm
content: I had exactly the same symptom please see the attached pic of main board, yellow marking of removed U25.Red arrow points to its pin 5, which had welded to the pad, due to over-current.Troubleshooting, I found that there was a short circuit in the SY3.3 3.7V rail, so I removed R350 (zero ohms), to separate and narrow down.Testpoint TP94 was still shorted to ground.So I injected 3.3V to observe heat, indicating the defect.Unfortunately it appeared to be the U7 IC; AKM Digital Signal Processor AK7755;https://www.alldatasheet.com/html-pdf/672974/AKM/AK7755EN/55/1/AK7755EN.htmlAs this processor needs to be programmed, I considered the unit beyond repair.BRG

author: eevbrob
author_rank: Newbie
timestamp: December 27, 2024, 10:56:54 pm
content: I can confirm the issue:exactly same symptoms: U25 heavily burned,after removal of U25, short circuit at Pin 6 / SY3.3 3.7V rail,I had two boards with these symptoms (both were offered as working! :-( )One with L48 having visual signs of burning and one with L48 ok, but U17 destroyed (hole on top)I applied 3volts to pin 6 (limited to 1Amp) (U25 still removed) via external power supply and found in both boards U7/AK7755 getting hot.So AK7755 seems to be the reason, so boards beyond repair.As this is the same failure as described by girander it SEEMS TO BE A SERIAL FAULT OF JBL EXTREME 2 PCB!--> keep hands off dead JBL EXtreme 2 boxes!

author: hammeron
author_rank: Newbie
timestamp: April 07, 2025, 02:56:02 pm
content: Quote from: girander on October 23, 2024, 07:41:25 pmHi, I am an embedded sw developer, and I want the share the possibility that the AK7755 is programmed during boot up by the main mcu. It seems to have neither internal flash nor EEPROM.. So I would definitely examine the possibility to replace that IC.Btw - came here after troubleshooting a failing xtreme2, where L48 was vaporized. Have not examined the board for shorts yet.

author: hammeron
author_rank: Newbie
timestamp: April 10, 2025, 11:29:20 am
content: In my case it was C311 (10uF 0805 MLCC capacitor) that had been shorted. Replacing L48 and C311 and "repairing" the burnt up traces, and my Xtreme2 is rocking again. Could not have done it without the service manual though.This thing is missing a fuse I presume. It should not vaporize components on the PCB.

author: pejjo
author_rank: Newbie
timestamp: June 28, 2025, 04:01:58 pm
content: I can confirm that a replacement of the AK7755 is possible and in my case successful. I also had to replace the switching regulator since i lost itduring the repair.Its rocking again!!

author: henmill
author_rank: Contributor
timestamp: July 12, 2025, 04:33:43 am
content: Hi @pejjo, @hammeron,Do you mind sharing a part number for the burnt regulator? I'm sure I could find a 3.3V switcher with the right FB voltage and pinout on DigiKey with enough sleuthing, but not getting any hits for "SY8201" as the BOM says.I appear to have the same issue with toasted U25 but have not had much time to trace the downstream problem yet. Hoping for a shorted cap and not needing to replace the AK7755. But it's great to know it can be done without needing to worry about flashing a firmware to it! I haven't yet removed the main PCB and it would be so cool not to!I just quickly probed across C311 and found not a short but about 620 ohms. Eh? Also seeing ~1M across L48. I will investigate this more closely soon, but perhaps the ferrite has acted as a fuse in a similar way to your case @hammeronIt's worth noting on this unit that there are some pretty substantial cracks in the housing. Maybe a good fall shorts an MLCC and all heck breaks loose after that... That is my hope anyways. Father-in-law claims "I never dropped it"Any theories on this failure mode besides: something on 3.3V rail shorted and no fuse to save us? Audio chip frying seems scary.. latchup on an input perhaps?here are some pics: