laptop screen doesnt always turn on

[angryassdrummer]

ok this one is hard to describe. i tried telling a computer geek mate but he had never heard of it before.
i have a toshiba laptop satellite 500 i think
anyway, the last 18 months or so, sometimes, would say about 50% of the time when i turn it on the screen doesnt turn on. the lights on the keyboard all come back on but no screen. i can open dvd tray etc but no screen
other times it comes straight on, and when its on there are no problems whatsoever.
if it doesnt turn on, i let it sit there OR try turning it off and on several times till out of the blue it will come on
i cant work out why it does this and why sometimes it works first time others it doesnt
very frustrating as my desktop is broken at the moment i need the laptop everyday. cant afford to get it sent away so if i can work out if this is common or what might be causing it i will take it to a professional for a one day repair or the pc geek mate should be able to fix it.
anyone heard of this?
oh, thought it might of been the battery, as sometimes i try turning it on without the battery in and it turned on, BUT it works sometimes too with battery in
i always have it plugged in, is this bad?

[edDV]

ok this one is hard to describe. i tried telling a computer geek mate but he had never heard of it before.
i have a toshiba laptop satellite 500 i think
anyway, the last 18 months or so, sometimes, would say about 50% of the time when i turn it on the screen doesnt turn on. the lights on the keyboard all come back on but no screen. i can open dvd tray etc but no screen
other times it comes straight on, and when its on there are no problems whatsoever.
if it doesnt turn on, i let it sit there OR try turning it off and on several times till out of the blue it will come on
i cant work out why it does this and why sometimes it works first time others it doesnt
very frustrating as my desktop is broken at the moment i need the laptop everyday. cant afford to get it sent away so if i can work out if this is common or what might be causing it i will take it to a professional for a one day repair or the pc geek mate should be able to fix it.
anyone heard of this?
oh, thought it might of been the battery, as sometimes i try turning it on without the battery in and it turned on, BUT it works sometimes too with battery in
i always have it plugged in, is this bad?

Does the VGA out work to an external monitor?

Most likely a failing inverter board that converts DC to AC for the florescent backlight. If not the backlight has failed.

[angryassdrummer]

if it was the backlight, wouldnt it never work?
like i said, it comes on straight away 50% of the time other times i have to keep turning it off and on till it does.
oh i should say, when the screen doesnt come on, the lights are on the keyboard but it doesnt sound like its fully on, as in its not as loud.
always comes on eventually tho more a total hassle if its not right away

[edDV]

if it was the backlight, wouldnt it never work?
like i said, it comes on straight away 50% of the time other times i have to keep turning it off and on till it does.
oh i should say, when the screen doesnt come on, the lights are on the keyboard but it doesnt sound like its fully on, as in its not as loud.
always comes on eventually tho more a total hassle if its not right away

Other than checking VGA out to an external monitor, try shining a light on the screen to see of the screen is still active. If so, the back light isn't on. That could be due to the back light tubes or the power inverter. My guess is the inverter because it works half the time. The repair shops usually replace both.

[redwudz]

The other possibility is that the switch that turns off the display is messed up. When you close the lid, that switch shuts off the display. If it hangs up when the lid is opened, it could be the problem.

I always keep my laptops plugged in as I use them at home. It might shorten the battery life somewhat, but no other problems.

But edDV may be correct. I would also second his idea to plug in a VGA cable to a desktop monitor and try that. You would have to set that up in Displays when the laptop is working and wait for it to fail again to see if you have a picture on the monitor. If not, may be a more serious problem.

[Bjs]

Test the screens position ... move the screen to full open position and back (not closed position) ... if it blanks out you may have a worn out cable between the motherboard and the lcd panel.

Backlights normally completely die or slowly ... they don't turn on and off ... be looking more like a gpu fault if everything else has been tested and confirmed.

[Nelson37]

When it comes on by itself, is Windows already loaded or does it indicate just now starting to boot?

The "loudness" issue you mention makes me wonder if this is the screen failing to display, or the PC failing to boot. Failing power supply and especially bad battery could cause this. You state that it has successfully booted with the battery IN. A more important question would be Has It Ever FAILED TO BOOT With The Battery OUT?

The external monitor hookup will answer most questions.

[SLK001]

You can test to see if the inverter is bad by holding a flashlight at a very high oblique angle at the screen. If the display is working properly, you will be able to see very dim images and text on the screen with the light. If it is a bad inverter, you can pick up on for less than $20 on ebay.

I've had to replace inverters on Toshiba Satellites quite a few times (but Toshibas are all that I fix).

If no TV out, then it's time to get another laptop.

[gadgetguy]

I won't repeat what others have said, and you need to follow their advice and verify the problem, but the symptoms, as described, exactly match what I was experiencing with a Dell laptop. The solution was to replace the screen (including backlight and inverter). It's a 5 minute job if you can find a replacement screen at a price you're willing to pay. It's possible to replace just the backlight or just the inverter, but you have to be a lot more careful and you have to make sure the inverter and light are designed to work together. Replacing a backlight is also a delicate procedure. In my case, there were at least 3 different screen/backlight/inverter combinations available for my model and none of them matched the inverter that was originally shipped in the laptop, so buying them as a package made more sense than trying to find the individual replacement parts. The replacement screen cost me about $70, (used, with a big scratch in the screen), but I could have paid up to $175 (still used, but flawless).

[classfour]

The problem with laptops is "are they worth more as parts?"

New ones are cheaper than a major fix.

[gadgetguy]

The problem with laptops is "are they worth more as parts?"

New ones are cheaper than a major fix.

It depends on your needs. I had to repair the above laptop because new laptops don't come with parallel ports and the software I have this laptop for uses a para-port security dongle.

[classfour]

Gadgetguy - Right on that: I hang onto my older Dell because the newer one that I bought last year didn't have anywhere near the ports and features of the older one.