z935 p300 Toshiba Portege Backlight fuse

[technoob]

Hi, I recently ordered an LCD from laptopscreens.com. Plugged in the new LCD, graphics are there but you can only see them with a flashlight. I guess I shorted the backlight fuse because I did not remove the battery when replacing the LCD. Now the backlight does not work on the new LCD nor the old cracked LCD.

Laptopscreen.com agent referred me to this link:

https://www.laptopscreen.com/English...to+blown+fuse/

Now how will I ever find this fuse for my Toshiba Portege z935 p300?

The only way I can think of is if I take pictures of the motherboard and maybe someone on here will be able to help me find it? I am willing to pay with Bitcoin to anyone who helps. Please

[Sadistic Taste]

Re: z935 p300 Toshiba Portege Backlight fuse

Upload some good pics, and someone will be happy to help. From the link you sent, the fuse is clearly marked F1 3A/32v. which looks like a 0603 smd fuse.

[James234524]

Re: z935 p300 Toshiba Portege Backlight fuse

Hi all.
I have a Toshiba Satellite z930. P/N is PT23LA-01100N. I suspect I have a failed backlight fuse on my motherboard.
I have attached a photo of the motherboard and highlighed the component which I think might be the backlight fuse. It measures open circuit with a multimeter. Does anyone have any idea if this is the correct component?

Thanks
James

[budm]

Re: z935 p300 Toshiba Portege Backlight fuse

The one with the 'N' on top is the fuse.
Is there any thing printed on top of that white part?
Btw what DCV do you get on each end of that part with ref. To Gnd?

[James234524]

Re: z935 p300 Toshiba Portege Backlight fuse

The one with the 'N' on top is the fuse.
Is there any thing printed on top of that white part?
Btw what DCV do you get on each end of that part with ref. To Gnd?

Hi.
The part with a 'N' is a fuse, yes. But it is the fuse of the main power supply from the laptop charger. As far as I can tell, it has nothing to do with the backlight power supply. The voltage at the fuse marked 'N' measures 18VDC with ref to GND.
The image is 100% intact on the LCD but it is only viewable when you shine a torch on the screen (due to no backlight).
I have tried measuring the voltage on the test points on the board for the various lines going to the LVDS connector and through the ribbon cable to the LCD. There are not voltages measureable with a multimeter so the fault is with the power supply going to the LEDs I think.
I cannot see anything which I believe to be the LED backlight driver IC on the side of motherboad shown in the photo. I have not yet removed the motherboard and inspected the other side. Does anyone have any idea where the LED driver IC is located? Or does anyone know what kind of voltages to expect going to the various LED backlight lines?

[James234524]

Re: z935 p300 Toshiba Portege Backlight fuse

The one with the 'N' on top is the fuse.
Is there any thing printed on top of that white part?
Btw what DCV do you get on each end of that part with ref. To Gnd?

Update...
Still no luck with identifying the fuse for backlight power on my Toshiba Satellite Z930 motherboard.

I've completely removed the motherboard and taken some decent close up pics and marked them up with what I have determined so far. There are 2 fuses marked 'N' and 'R' on the same side of the motherboard as the LVDS connector but neither of them has anything to do with the LCD. The "N" one is for the mains AC charger and 'R' one is for battery power.

I have read that the fuse for backlight power is often close to the LVDS connector but on the reverse side of the motherboard (http://www.laptop-lcd-screen.co.uk/b...Backlight.aspx)

There are numerous small components in this area on the reverse side of the motherboard but unfortunately I don't really know what I am looking for...

Images of top side of motherboard (LVDS connector side):
https://postimg.org/gallery/ijt1asde/

Images of reverse side of motherboard:
https://postimg.org/gallery/ii9erix0/

Any help identifying the backlight fuse would be most appreciated.
Cheers
James

[meritosari]

Re: z935 p300 Toshiba Portege Backlight fuse

Is there any pin from this IC connect to LVDS connector?

[James234524]

Re: z935 p300 Toshiba Portege Backlight fuse

Is there any pin from this IC connect to LVDS connector?

For anyone interested - this is what I suspect was the cause of the backlight failure on my Toshiba Satelite z930. The component in the bottom right hand of the attached picture measured hard open circuit. I was told by someone else that the power supply for the LED backlight driver chip (located in the LCD panel) goes into the LVDS connector on pin 1, so makes sense).

Unfortunately for me, I put the board back together and it is dead.
I get a power LED but no boot up sequence happens and it shuts itself down after about 10 seconds. I don't think it is salvageable now. I guess I wasn't careful enough in handling the board when I was working on it