toshiba da0blimb6f0 rev:f

[mazenkataya]

please help this laptop turn on cpu fan turn on and off
all votages on cails founded , 1.05V, 1.35V, 1.7V, 3.3V, 5V. 19V rail is there

i try bios and another bios chip from working mbo the same issue .

on power supply it have consumption 400mili ampere

[mon2]

Re: toshiba da0blimb6f0 rev:f

Are there other markings on the logic board to help to identify the motherboad?

Do you have schematics available ?

Remove all power and place the meter in resistance mode (2k scale is ok).

Check the resistance to ground for each coil. Report any low resistance readings.

The power down cycle may be due to one of the power rails shutting down from what it believes is an excessive current draw. A low resistance will indicate a short from perhaps a bad capacitor.

[mazenkataya]

Re: toshiba da0blimb6f0 rev:f

Are there other markings on the logic board to help to identify the motherboad?

Do you have schematics available ?

Remove all power and place the meter in resistance mode (2k scale is ok).

Check the resistance to ground for each coil. Report any low resistance readings.

The power down cycle may be due to one of the power rails shutting down from what it believes is an excessive current draw. A low resistance will indicate a short from perhaps a bad capacitor.

the lowest value i get 0.118k ohm

[mon2]

Re: toshiba da0blimb6f0 rev:f

That is a good resistance reading - you do not have a short.

Can you identify the logic board ?

What is the history of the unit ?

Liquid damage ?

Was it working properly and just one day, started to do this power cycling ?

Does this bios from THIS logic board work in the known good logic board ?

Just wanting to confirm that the bios is truly compatible for use on this logic board.

[mazenkataya]

Re: toshiba da0blimb6f0 rev:f

That is a good resistance reading - you do not have a short.

Can you identify the logic board ?

What is the history of the unit ?

Liquid damage ?

Was it working properly and just one day, started to do this power cycling ?

Does this bios from THIS logic board work in the known good logic board ?

Just wanting to confirm that the bios is truly compatible for use on this logic board.

i try the bios chip on another mbo with the same model and it worked normally and the laptop starts

history of this laptop came from another repair shop they try replacing io
while observing bios oin number 1 on osciloscope i get not response and no spi data with io

[mon2]

Re: toshiba da0blimb6f0 rev:f

No direct experience with this but it sounds like you know already the fault.

The last repair shop worked on the IO (EC / KBC?) controller and it must be the SPI bus master. If you see no SPI activity then it sounds logical that the upstream component is faulty or needs to be reprogrammed with the proper firmware.

What are the details of the IO controller ? What is the part # ?

I would check the voltages on the known good logic board and compare against the non-working unit.

After this verification, either the controller is defective or not programmed to act like the SPI bus master.

Be sure to confirm that the SPI flash is being powered.

Trace the pins to see if there are any middle current limit resistors that may be damaged or missing between the flash & IO controller.