COWIN 7 Wireless headphones

[daveyk]

Kid brought me his headphone smelling like something burned up.  The side that contains the battery has only one active part.  Looks like the li charger IC.  It is 5 pin marked 55BA and quite burned up.

In the meantime, I order another pair for him off of amazon, but like any tech, it would be cool to fix the old ones.  The other ear that contains the bluetooth logic isn't damaged as far as I can tell, only the side with the lithium battery and this chip.  USB power goes to this chip and the battery hooks to it.

Anyone with experience fixing something like this or where to find schematics for wireless headphones?

[fzabkar]

Is there an FCC ID anywhere?

TP4055, Top Power Asic, single-cell Li-Ion battery charger with reverse battery positive and negative polarity protection, 4.2V, 500mA, marking 55bM, SOT-23-5:
http://www.tp-asic.com/res/tp-asic/pdres/201203/TP4055_42.pdf
http://www.tp-asic.com/te_product_a/2009-05-20/1238.chtml
https://www.aliexpress.com/i/2255800831044176.html



Linear Tech appears to have pin-compatible chips, eg ...

https://www.analog.com/media/en/technical-documentation/data-sheets/405442xf.pdf

I'm betting this is the original headphone manufacturer:

https://fccid.io/2AB5T
https://fccid.io/2AB5T-E7

[daveyk]

Wow, that's exactly the part.  Thanks!! How did you find it?

[daveyk]

Order a couple packs of those chip and some battery varieties from Alli.  I alsi found some nice assortment of Microusb sockets.   I should have in about 2-3 weeks.

Thank you again!

[NiHaoMike]

If space allows, add a 1 ohm or so resistor in series with the USB input, that will help keep the chip cooler and avoid a repeat failure.

[fzabkar]

Wow, that's exactly the part.  Thanks!! How did you find it?

I performed a Google image search for "SOT-23-5" "lithium charging" and found similarly marked ICs from the same manufacturer. Then I went to the manufacturer's web site and examined the products for likely candidates.