Toshiba L655 No diplay

[bluestone]

A customer brought this toshiba l655, core i5 laptop to me and the problem is it will power on but no display, i have changed the cpu and ram but still, i gave it an external monitor and still nothing showed, have anyone come across any problem like this before?

[selldoor]

Re: Toshiba L655 No diplay

Dont know the problem but has this got a separate graphic card. Take it out, clean and reseat it? -How is it cooled? check fan/heatsinks

[Claudio Silva]

Re: Toshiba L655 No diplay

Change the Graphic card it seemes to be graphic Card issue.

[bluestone]

Re: Toshiba L655 No diplay

there is no separate card on the board, but it seems the power to the cpu is not accurate cos it is 0.5v, think it should be at least 1.0v, can that cause the probem?

[spidey]

Re: Toshiba L655 No diplay

is there a nec/tocin capacitor ?

[fddizon]

Re: Toshiba L655 No diplay

capacitor issue... reflow graphic controller ic

[tomodachi]

Re: Toshiba L655 No diplay

Same issue here, I can get video via VGA output but no displayon own screen, tried to reflash bios but no change, anyone ?

[rtstorm]

Re: Toshiba L655 No diplay

if you can do the reballing on GPU. When you disassembe the laptop was it clean? If it has a lot of dust on heatsink (i mean like peace of sponge) that can tell you that poor GPU was overheated and ball under disconnect from pads, or in worst scenario the IC itself died.

[tomodachi]

Re: Toshiba L655 No diplay

I am the first who disassembling the unit and there was a very little dust in cooling fan makes me guess its not overheat related. checking out the schematic, GPU runs HDMI, VGA and LCM. VGA and HDMI output is working well, and I guess this means GPU is good.

[/IMG]

[bammbammfran]

Re: Toshiba L655 No diplay

There is a good chance that it is not the GPU since you have external

Did you try safe mode with no external monitor hooked up ?
Do you see any glow on the screen (usually the bottom right corner shows the best)
could be a bad screen, bad wiring cable or even a popped fuse on the mobo.
You'll have to open the lcd and check to see if voltage is getting to the screen
that should be an led screen on that model so the power in pins are near the one end of the connector

[rtstorm]

Re: Toshiba L655 No diplay

A customer brought this toshiba l655, core i5 laptop to me and the problem is it will power on but no display, i have changed the cpu and ram but still, i gave it an external monitor and still nothing showed, have anyone come across any problem like this before?

you say that you connect to external monitor and did not get picture, that is why i told that it may be GPU faulty. But if you have working VGA or HDMI then the GPU is ok.

[tomodachi]

Re: Toshiba L655 No diplay

There is a good chance that it is not the GPU since you have external

Did you try safe mode with no external monitor hooked up ?
Do you see any glow on the screen (usually the bottom right corner shows the best)
could be a bad screen, bad wiring cable or even a popped fuse on the mobo.
You'll have to open the lcd and check to see if voltage is getting to the screen
that should be an led screen on that model so the power in pins are near the one end of the connector

I m pretty sure LVDS wiring and screen is good ( tried with good known one before) but I realized there is no voltage at LVDS connector, according to schematic at least there must be 3.3V for screen backlight isn't it ? Let alone the backlight, I can't see any glow on screen.
see here

I m not getting any of these voltages mentioned in schematic
[/IMG]

[bammbammfran]

Re: Toshiba L655 No diplay

You should have power there when it is running
Probably at least the 5 volts that runs the lcd controllers and then the backlight voltage which might be full power from the bat or ac .
so if your cable/ribbon is definitely ok, then you'll have to check things right at the motherboard

I think there is a fuse or two right next to the connector on the motherboard

[tomodachi]

Re: Toshiba L655 No diplay

Ok then I 'll see it tomorrow and let u know, thanks.

[ry x hunter]

Re: Toshiba L655 No diplay

bios issue

[ry x hunter]

Re: Toshiba L655 No diplay

try to reprogram bios ic

[tomodachi]

Re: Toshiba L655 No diplay

my bad . problem turned out to be a bad LCD. I didn't pay attention enough while I was trying new screen. now the display is ok with new LCD. thanks all !