T61 either not booting or showing rainbow of death

[macant]

I have a ThinkPad T61 which I bought used last year. I was running it on XP, then a couple weeks ago I installed a dual boot with Ubuntu, using GRUB to choose the operating system to boot into at startup. So far so good until a couple days ago, when after a long day at the bottom of my book bag the laptop would no longer start up.

Instead, sometimes it simply displays nothing (dark, blank screen) and the only lights that stay on are the little (z) or sideways (N) light and the battery light, but far more often, without any preamble, it starts displaying an endless series of full-screen colors, in this order, for about 3 seconds each: white, black, gradient from black to white, gray, red, green, blue, repeat forever. That's all that happens; no BIOS screen, no GRUB boot loader, nothing. Inserting an Ubuntu boot disc does nothing; the drive indicates that it recognizes the disc, but ignores it.

Just at the moment, after about 8 startups in a row where it did the series of full-screen colors, it's going back to the dark, blank screen way of doing things. I think if I leave it on for about half an hour the colors will come back. What do you think? Information about this on the web is hard to come by.

[RealBlackStuff]

Welcome to the forum.
Sounds like yours has nVidia graphics.
T61 machines are notorious for developing display problems due to a manufacturing fault in the nVidia GPU (Intel GPU is OK).
Check the date behind the serial number on the bottom of the laptop.
If it is 08/07 (interpret as YY/MM) or earlier, and you have nVidia, you're SOL.

[macant]

Yup, 08/07. Don't know if it has a nVidia GPU, though; no nVidia stickers and there's probably no point cracking it open. Although I guess I'll have to if I want to pull out the hard drive and start copying stuff off.

[RealBlackStuff]

What is the TYPE and PRODUCTID on the same sticker?

[macant]

TYPE: 7661
PRODUCT ID: 7661M94

[RealBlackStuff]

Ex factory:
T61 (7661-M94)
Based on 7661-12U: T7100(1.8GHz), 2GB RAM, 100GB 7200rpm HD, 14.1in 1280x800, Intel X3100, CDRW/DVD, Intel 802.11agn(n-disabled), Bluetooth, Modem, 1Gb Ethernet, UltraNav, Secure chip, 6c Li-Ion, WinXP Pro
Yours has Intel graphics.
You may have a defective screen.
Being buried underneath a pile of books, and being lugged around campus, does wonders for the LCD...
It could also be a loose LCD connector inside the lid, or inside the laptop.

[macant]

If I plug in an external monitor cable, the monitor is simply ignored and never used. I'm assuming the operating system never boots at all since waiting for it to boot and then holding down the power button for a second causes the laptop to turn off.

Anyway, I guess it's time to go laptop shopping. For reference, how can I look up a ThinkPad by the product ID to see if it uses a nVidia GPU?

[RealBlackStuff]

Enter it in "Quick Path" here: http://support.lenovo.com/en_US/

Try Fn/F7 to switch to another display.

[macant]

It doesn't do anything when I try to switch between displays.

[RealBlackStuff]

Remove the HD, then try to boot from a Life-Linux-CD.
If still bad graphics, you'll need another mobo.

[macant]

Okay, thanks a lot for all your help. I'll try this after exams hopefully, see if I get anywhere.