Sot23-6 assisting wifi module - Page 1
Forum section: electronics / repair

author: NielsChr
author_rank: Newbie
timestamp: January 14, 2022, 10:54:14 pm
content: Hi, I have JBL soundbar 5.1 from 2019. The soundbar it selv does still work. However it Can no longer Connect/sync to the wireless subwoofer og side speakers.I have opend it up and inside is a sandwich of differentiere bords - the bord in the midle of this sandwich seems to take Care of the wifi communication - the board above this is the amplifier for the 3 channels inside the soundbar.I guess it Mighty have been a lille varm on this board as not Munch ventilation is pressent.Sinde this board is in the midle im not able to messure voltages on the SOT23 while powered on - sorry.Anyway I belive I have Found the component not Working. Its a SOT23-6 pin, and on top of is is stamped `ENABF`Im not sure what this chip does, but it must be relatd to the wifi, as this is the onlything not workingHope anyone in hele Mighty be able to helt identify this SOT23i have attached a picture showing its burned and part of the board.

author: NielsChr
author_rank: Newbie
timestamp: January 14, 2022, 10:55:42 pm
content: Fyr. CN1004 is the wifi antenna Connector

author: fzabkar
author_rank: Super Contributor
timestamp: January 14, 2022, 11:17:32 pm
content: I expect that the IC is a switchmode, step-down converter. It might help if you could determine the ground and Vcc pins, and the IC's connections to the 100uH inductor and capacitors.Can you identify any other ICs on the PCB? Perhaps they are manufactured by the same company?

author: NielsChr
author_rank: Newbie
timestamp: January 15, 2022, 10:07:56 am
content: Thanks, I Will Give it a try if I Can follow the connections and locate gnd /vcc. Right now its not possible to messure while powered up.i se the capacitors and sone resistors. But Can not locate the mentione 100uH inductor, whereabouts is this(Im not use to small components)

author: amyk
author_rank: Super Contributor
timestamp: January 15, 2022, 10:20:56 am
content: SY8201ABC, actually recommends 10uH inductor

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: January 15, 2022, 10:44:47 am
content: Quote from: NielsChr on January 15, 2022, 10:07:56 amIt's the square black thing just above the IC. the 100 marking means 10uH

author: NielsChr
author_rank: Newbie
timestamp: January 15, 2022, 08:32:13 pm
content: Thank you all.I belive amyk is right about the linked ic. Its pin layout match what i messure.Gnd is gong to pin 2The capacitor is connected to 1 and 6The inductor is connected to pin 6I belive the output of this ic is 5 volt.The output (pin 6) Are wired to the external connector to the wifi module. This connector have pin specifikations printes on the board and States +5vSo now I only need to find a place Where to buy this in denmark, and figure a Way to solder this tiny Pice. thanks a lot, tour helt was reallly Great.I wounder if I Could find 5 volt elswhere on the board and simple hardwire it. This would be a permanentet 5v that the Logic Can not turn on/off. But Maybe that does not matter at all. (Wifi module would stay on)

author: fzabkar
author_rank: Super Contributor
timestamp: January 15, 2022, 08:54:45 pm
content: This IC (MP2357) appears to be pinout compatible:https://www.monolithicpower.com/en/documentview/productdocument/index/version/2/document_type/Datasheet/lang/en/sku/MP2357/document_id/223The switching frequency is much higher (1.4MHz versus 500kHz), so you may need to use a smaller inductor (4.7uH). It also requires an external flywheel diode.Digikey and Newark/Farnell have stock:https://www.digikey.com/en/products/detail/monolithic-power-systems-inc/MP2357DJ-LF-Z/9555312https://www.newark.com/c/semiconductors-ics/power-management-ics-pmic/voltage-regulators/dc-dc-adjustable-switching-regulators?st=mp2357Edit: I just realised the output current is only 0.5A.

author: NielsChr
author_rank: Newbie
timestamp: January 16, 2022, 09:47:37 am
content: At my local ee store, I see a lot of different Buck converteres -all with different freqencies and output current.Is there a Way I Can find the One getting closest to the original…i havelookex at other ic on the board to see for a manufactor for Them, and I see SST, LD an EMThis page is in danish, but there are the one I Can easyly get access to:https://dk.rs-online.com/web/c/halvledere/power-management-ic-er/buck-convertere/I know output needs to be 5v, and I also have the inductor size of 100uH.Afaik The Buck converter is only used to drive the wifi module as the output Vout goes to this and all other funktions does still work

author: fzabkar
author_rank: Super Contributor
timestamp: January 16, 2022, 05:57:48 pm
content: The inductor is actually 10uH, not 100uH (the second zero is a multiplier).

author: NielsChr
author_rank: Newbie
timestamp: January 17, 2022, 05:27:31 pm
content: Great to know, coz I have seen some schematics with 10uH and was wondering Why my circurit had 10 times that value. Now my circurit fits more into std schematics showen with alternative components.Thanks for pointing this out.

author: NielsChr
author_rank: Newbie
timestamp: January 17, 2022, 06:38:40 pm
content: i have looket for a alternative. And Think the Texas lm2724y May be a candidate - this is avalible for me to purcase.i have not yet verifyed, but looking at the back of the circurit could indidate r1 and r2 as Being 22k and 6k8I know outputs need to be 5v, but does not know the input voltage it could be anything..currently not able to messure while power is on.i have not yet seen any diodes, could that be the reason why it burned off in firstplace - should i add a Schottky diode to prevent this from happen again betjene inductor and pin 6(output)

author: NielsChr
author_rank: Newbie
timestamp: January 19, 2022, 10:18:49 pm
content: Ok, now I have tested while circurit is mounted and there is power to the soundbar.I have found that the motherbord powerspuply inside the soundbar is 3.3 volt.I have also found that if i `manually` supply 5v to the wifi module the wireless speakers starts to work- that god news. This is tested with an external powersupply connected to the wifi module Vcc (3.3v is not working)I have messure a usage of aprox 850 mA to the wifi module while 5 v is Applyed and speakers is playing Music - anyone know if this is this an expected consumption for a wifi / radio module ? (I was expecting something like 2-300 mA based on a guess)This leads me to conclude that the ic that is deffective is a `step up` From 3.3 v to 5 volt.Given the fact that this is a SOT 6 pin, have You any clue about what substitut ic I May use ?Or should I simply make a sepperate 5v supply and use that for the wifi module - it would workI do have 19 volt availbe also on the buildin power supply so maybe I should simply add a 7805 with a small capacitorInside the soundbar - og do you have any other suggestions how to fix easyly

author: thinkfat
author_rank: Unknown
timestamp: January 21, 2022, 09:38:07 am
content: If you go for this, rather use one of the switch-mode buck converter modules that you can find all over ebay. 19V down to 5V at 850mA with an 7805 - not feasible. Power dissipation will be almost 12W. The 7805 will just burn up.

author: thinkfat
author_rank: Unknown
timestamp: January 21, 2022, 10:20:32 am
content: Are you sure it's a step-up regulator? I've been trying parametric search with Mouser and LCSC (to also cover Asian brand manufacturers) but there are no synchronous boost converters in SOT23-6 with a switching frequency so low that they'd require a 10µH inductor. At least not with an output current of around 1A.