Remington R6150 electric shaver SMD component identification

[jorgemef]

Hello. I have a board with two transistor fried with reference I cannot sort out.
Any hint what those are?

A652 - Between Battery and chip Seems kind of bucket configuration
ECJD - driver for battery charger from external 12V. Also bucket configuration

Not sure if transistor, mosfet or other.

Could not find those SMD reference anywhere.

Appreciated any help.

[gamalot]

This is a very difficult one! My guesses are AO3406(A652) and BCW65C(ECJD).

[fzabkar]

Google image searches would suggest that the marking for the AO3406 is "A69T".

https://www.thuispmoi.com/index.php?main_page=product_info&products_id=624988

A09T -> AO3400
A19T -> AO3401
...
A69T -> AO3406
A79T -> AO3407

Could A6xx be a BAS16 diode?

[jorgemef]

Finally figured out one of the components and on the tail of the other one.

ECJD is a P-MOS. Tested with IRML6402 and works well. The one which I used as replacement is in fact part number EAYAP.

The A652 I was not so lucky but I figured out that is in some kind of step up configuration. Circuit in attachment.

Figured out that using external 3V as output to the microcontroller the board works.
So no I need to find some step up converter chip in the SOT23 form that puts out 3V in this configuration.
The capacitor and inductor values are just some random. Didn't measured it from the board.

Any SOT23 step up chip for 3V output to use in NIMH battery powered circuits?

Thanks,
Jorge

[fzabkar]

Something like these?

https://www.ti.com/lit/ds/symlink/tps61322.pdf
https://datasheet.lcsc.com/szlcsc/1810010717_MICRONE-Nanjing-Micro-One-Elec-ME2188A33M3G_C111932.pdf
https://datasheet.lcsc.com/szlcsc/Nanjing-Micro-One-Elec-ME2110C50M5G_C154497.pdf
https://www.hmsemi.com/downfile/HM6383.PDF
http://www.sumsemi.com/Upload/Datasheet/SUM5005.pdf
https://www.gtic.com/Uploads/Temp/file/20230216/63ed9938576a4.pdf (GPD0201)
https://www.ecmos.com.tw/wp-content/uploads/2021/12/EC9202_5D23N-Rev.F003.pdf
http://www.md-ic.com.cn/download/MD3156.pdf
http://www.szecm.com/uploadfiles/files/20160706093933_4218.pdf (EC2306)
http://www.szecm.com/uploadfiles/files/20160706094041_7812.pdf (ECHXXX)

It appears that a switching frequency of 350kHz is typically matched with a 22uH inductor whereas a 1MHz frequency requires a 2.2uH inductor.

[jorgemef]

I measured the L and C and got cout 48uF and L of 100uH. Maybe of old technology of 100Khz.
Would there be a problem to use the new stuff with this 100uH? In Ali the old stuff (XC9111A30) is more expensive (4-5x) then the new chips and I have around some step up boards with PHOI-TPS61040 and MT3608-B628, which I could reuse and fit FB network with some 4020 resistors. But those work at 1MHZ and this 100uH seems too much.

Cheers,
Jorge

[jorgemef]

Further updates: already replaced with a B628 with a kind of dead bug configuration and works fine now.
Used a FB network with 41K + 10K and gives 3.015V which is good.

Thanks for all the help.

Cheers.

[fzabkar]

I think the "560" inductor in your circuit diagram is probably 56uH (56 x 10^0). This makes me wonder how you arrived at 20uH for your boost inductor.

[jorgemef]

I measured the 20uH and was in fact 100uH

[fzabkar]

I measured the 20uH and was in fact 100uH

Did you measure the 560 inductor (to test your equipment)?

[jorgemef]

No, did not, but I trust it. It is a DE5000.

The 56uH seems a smoother for the pulses managed by the Mosfet as Vin is 12V for 2,8(3)V battery so didn't focused on that.

I was more in doubt for the booster part as I thought the 100uH from the small coil could be too much for the 1.2MHz from the B628. It seems to work anyway. Maybe the B628 throttles the switching frequency.
The small inductance from the booster I tested it with 1KHz setting.

Adding simulation with TPS61040 as could not find the spice model for MT3608. The FB value are different with TPS61040 requiring 1.23V and MT3608 requiring 0.6V. Hence the FB network I ended up using is not the same as what is in the LTSpice simulation.
The Vin (pulse) is provided by the microcontroller which I could not figure out which one it is. It is a 20 PIN microcontroller with Pin1 as Gnd and pin20 as VDD. No markings except under side as bcBK8WTT.

[fzabkar]

Wow, that's a lot of work for a shaver!

FWIW, PICs have Vdd on pin #1 and Vss on pin #20 ...

[jorgemef]

Was just a hobby and is a nice shaver with Titanium blades. I paid 50 euros for it when I bought it at Lidl.
Unfortunately the water resistance part is just temporary. Similar problems happened to me on a phillips.

If I would have the schematic would had done it in no time. Without it there was a lot of work.
Initially all parts where ok and a few traces where corroded, but I managed to mess the mosfet by connecting it without batteries. So VGS threshold was surpassed. Later attempting to reverse engineer the mosfet part I fried the voltage pump by applying 12V to it.
Now that I understand which parts they are I understand the process.
Best thing is the pile of parts is now back together and not messing my storage. And no more water on shavers on my end from now on.