HL91 Black screen problems

Hi All got kinda of a strange problem, I work for a school and we have 90 of these Laptops.
So far of the course of 2 weeks I have 5 that just wont boot anymore.
You can power on the system about 3 seconds later it will turn off then auto turn back on and display nothing.
Back light doesnt come up, HDD shows no activity, Power light stays solid, wireless light is on, I can hear nothing from the HDD.
Have stripped out all hardware (RAM, HDD and such)
Still the same thing.
These all have the intel graphics cards in them.
Kinda getting worried as 5 in 2 weeks all having the same issue, and I have another 85 in class rooms. All are out of warrenty.

Any help or idea would be great

Cheers

Ra

 

removing RAM won't help, it will not boot withour RAM at all.

Try external displays, and see if you have some output there.

Good luck!

 

Yep one of the first things I did was throw a monitor on it, nothing on that screen either.
And to clear up about the RAM I pulled both sticks out, and replaced them we known good ones from another HL91 that working fine. sorry i wasn't clear on that.

Getting real worried about it now as I just been told that one of the teachers laptops (same model) did the same thing.

 

Sorry, can be a thousand plus one thing.

Are you sure they have intel (onboard) graphics?

Maybe this can help you -> http://service1.marasst.com/Compal/JHL90_91/Service Manual/JHL90 service manual-Final-0725.pdf