liitokala charger

[m3vuv]

hi all ive a liitokala lii-500 charger thats died,does anyone know where i can find a schematic for it?,cheers Paul m3vuv.

[shakalnokturn]

No schematic, I have the same charger.
The 12V adapter supplied with mine went intermittent very soon.
Have you checked yours?

[m3vuv]

yup my adaptor is fine,just the charger wont power up

[Miwer]

I have one of those too. Also looking for a schematic.

Mine died after being dropped on the floor from a table. I replaced a TL431 vref and a transistor on the power input to make it work again, but now it seems a bit "wonky" as it does not correctly measure the voltage on the batteries. I can't seem to find any other faults on it, but it's not easy without a schematic. No visible damages, but I'm not sure if the drop could have caused a pcb via to crack, and make bad connection.

[Miwer]

yup my adaptor is fine,just the charger wont power up

Just wanted to follow up on this, with some pictures.
You need to check the voltages around U2 and Q27 - you can see my measurements in the pictures. The 5v regulator in this charger is more or less directly copied from the TL431 datasheet (apart from the resistor values).

I had to change both the TL431 (U2) and the NPN transistor (Q27) in mine.
Now beware - the chinese "431" marked part is actually not pin compatible with the TL431 from Texas Instruments, that I had. The pinout actually matches TL432 instead, so I had to flip my TL431 around, and connect a wire from anode to ground, as you can see in the picture.

From the datasheet: "The TL432 device has exactly the same functionality and electrical specifications as the TL431 device, but has different pinouts for the DBV, DBZ, and PK packages."
If I had to purchase a replacement, I would get the TL432 instead, but I already had the TL431 so I couldn't be bothered.

As for the NPN transistor (Q27), I believe any generic NPN transistor will work, as long as it can handle the current draw of the Liitokala (only the logic/display/etc., not the charging) - I just used whatever high current NPN transistor I could find. In my case I used a ZXTN19100CFF - maybe overkill, but it works.