Usb rechargeable hair clippers blown tp4056 and zener diode

[lcdcaps1]

Hi
all
I have a usb rechargeable hair trimmers that should work plugged in and charge
it stopped working no led norhing

I've opened it up and see the tp4056 chip has blown
There is a zener diode that I tested and get a near short ohms reading no matter which way my leads are
I don't know what to replace this with
Please help
thanks so much

[stj]

a 5v1 zener - 500mW probably,
it is to protect against a bad psu so check the psu is giving a clean 5v or less.
maybe upgrade the zener to 5v6 but it doesnt explain the chip unless somebody tried to run the motor while the psu was plugged in

[stj]

actually i'm slightly wrong, the zener is to stop the motor spiking the chip,
so if you can fit one - use a 1w or higher diode

[lcdcaps1]

actually i'm slightly wrong, the zener is to stop the motor spiking the chip,
so if you can fit one - use a 1w or higher diode

Thanks for the reply
When you say a 1w diode
is that still a 5v1

[petehall347]

did you test the diode on the board ? if so either remove it to test or disconnect the motor

[lcdcaps1]

did you test the diode on the board ? if so either remove it to test or disconnect the motor

Yes I tested the diode it was a showing low ohms reading both ways

[stj]

if you left the motor connected you will be seing the motor windings.
desolder the motor wires.

did you use this while it was charging btw?
i'v never seen a tp4056 cooked like that!
maybe the battery needs to be checked!

[lcdcaps1]

if you left the motor connected you will be seing the motor windings.
desolder the motor wires.

did you use this while it was charging btw?
i'v never seen a tp4056 cooked like that!
maybe the battery needs to be checked!

Thanks for the reply
I will do that
does that mean the Zener diode would still be ok
After speaking to the person who gave this to me, to look at
They said they plugged in another cable that had the same connector but the power adapter was different
was not usb
I believe that this is why the TP4056 blew

I I replace the TP4056 and deal with the burn damage
will it work again or should I replace the zener diode as well with a higher one
Thanks

[lcdcaps1]

Can I use
1N4734A
5v6 1w

instead of smd

[stj]

if it fits,
make sure there is room to put the case together over it
but the original may be good still

[lcdcaps1]

if it fits,
make sure there is room to put the case together over it
but the original may be good still

Is there any way to know if the Zenner diode is ok without removing it

[lcdcaps1]

if you left the motor connected you will be seing the motor windings.
desolder the motor wires.

did you use this while it was charging btw?
i'v never seen a tp4056 cooked like that!
maybe the battery needs to be checked!

You were right
I got 1.6 ohms across the motor terminals and
i got 1.7 ohms across the diode both ways

i got 0.002 v drop both ways

[petehall347]

did you disconnect the motor yet ?

[lcdcaps1]

did you disconnect the motor yet ?

In the process of doing it

[lcdcaps1]

I am thinking that should i replace with a new better zenner diode as I am replacing the chip

[lcdcaps1]

Would it be better to replace it with a 5v1 diode or a 5v6 diode, please
i think the glass might be cracked

[stj]

you could use 5v1,
normally you wouldnt use a zener across a motor so i dont know why it's there.
you would use a 1N4007 rectifier

[petehall347]

maybe using it to regulate motor speed ?

[lcdcaps1]

maybe using it to regulate motor speed ?

Thanks for the reply
I can replqce with a 5v1 zener diode smd which is 0.5 w
or 5v1 zener diode 1w which is through hole

I'm thinking if I replace with the 1w zenner diode it will add a bit more protection
any thoughts please
Thanks

[stj]

a 1w will take more stress before failing - if it even did fail