Toshiba Satellite C660D - dead motherboard

[Lukisek]

Hello. I have Toshiba Satellite C660D laptop with LA-6843P motherboard. When I plug in power adapter then none of led light.Power on button is ok, checked. I figured out that KBC chip is very hot after a few seconds when I plug in DC adapter. I measured all VCC pins in this chip and it is equal to 1,7 VDC, but by schematic it should be 3 VDC. Is it possible that no sufficient voltage causes this issue that chip is hot? Mosfets next to power are ok. 19 VDC is also on battery pins, so charger should work fine, but diode doesn't light. This chip is KB926QF E0. Did you have similar problem?

Regards,
Lukisek.

 

[BigBoss]

If IC is hot and the supply voltages are dropped down to 1.7V instead of 3V, the IC has gone.
Voltage dropping occurs because of over current and regulator circuit gets into protection mode.
It's still available

0.99US $ |Nouveau KB3940Q A1 KB9012QF A4 KB926QF E0 KB926QF EO 100% MEC1404 NU MEC1322 NU QFP 128 | AliExpress

Achetez malin, vivez mieux! Aliexpress.com

fr.aliexpress.com

 

[Lukisek]

Thanks for your fast reply. In this way I will buy the IC and will try to solder a new one. What is the reason that IC is gone? I thought that it will be power MOSFET, not IC...

Lukisek

 

[Lukisek]

Hey,

I just replaced KBC (the same model). After I plug in power supply and a battery, the charging led lights, but after about 10 seconds it is off. The same situation with power button. Power diode light for 5 seconds and then stop. Fan is not working while motherboard is on. ANd the next thing is that while charging diode is lighting then I can't power on motherboard. What should I check next?

Regards,
Lukisek.

 

[BigBoss]

Check the peripheral elements, someone forces the IC to flow much current.

 

[Lukisek]

Hey,

Thank you. I decided to postpone this fix because of my departure, maybe I will abandon this repair. Thanks for your help.

Lukisek.