toshiba c850 no power

[hazim]

hi i have Toshiba c850 plf/csf 45w uma dsc mb rev 2.1 with AMD chip and pch chip

problem that 20v on charger resistor is ok

but ic tps 1225c is very hot - no short in this circuit

i replace it but still to much hot

i replace io ene kb 930qf-a1 but ic 1225c still very hot

on power supply show 0.136 amps

i need you help thank you

[caspian]

Re: toshiba c850 no power

to get help, first upload the schematics of your laptop. I found the following one, but it does not have kb930:
https://www.badcaps.net/forum/attach...3&d=1538566332

[hazim]

Re: toshiba c850 no power

i'm so sorry this is exact schematic io nuvoton not ene kb i replaced io nuvoton but i'm confused between to motherboad toshiba in my shop

you'r right my frind this is mb photo

and ic 1225c circle by yellow

[caspian]

Re: toshiba c850 no power

In addition, I do not find IC 1225c in the schematics file.

[Conste]

Re: toshiba c850 no power

https://cdn.badcaps-static.com/pdfs/...2c6e6f33b6.pdf

This should be the datasheet of TI 1225C

[hazim]

Re: toshiba c850 no power

first i want to thank you

this mother board have ic 1225c on board and i see another 2 main board like this mb i see 1225c on it

but in the schematic i see another one

i search and get this ic datasheet

http://gulfup.co/50g713uywvpu

slvu735.pdf - 969 KB

[hazim]

Re: toshiba c850 no power

first i want to thank you

this mother board have ic 1225c on board and i see another 2 main board like this mb i see also 1225c on it i'm sure

but in the schematic i see another one tps 51123

this ic on mb is tps 51225c i'm sure

thank you

[piernov]

Re: toshiba c850 no power

If the TPS51225C still heats up after having been replaced most likely VREG3 or VREG5 is shorted to ground. Check resistance to ground on both those output.
Make sure the replacement chip has been soldered on properly.

[hazim]

Re: toshiba c850 no power

vreg 3 pin 3 is ok no short

vreg 5 pin 13 is ok no short

install new ic tps 51225c but very very hot

[caspian]

Re: toshiba c850 no power

check all the Mosfets which are connected to TPS51225c for being defective.

[hazim]

Re: toshiba c850 no power

after i visual inspection this mb i see mini small brunet above mosfet near the coil 5v

i replace it soon

mb power up but no data

i re flash bios - mb is ok

thank you so much my friends