t42 not booting, no video

[doors666]

i got a t42 from a friend, it doesnt work and i was hoping to fix it for a basic browsing machine for kids. When I switch on the machine, the ON and battery lights are on, the caps and num lock come on for a couple of seconds and then go off. I tried it on just the battery, just on the power with no battery, Tried an external monitor, with a winxp boot cd etc, but no use. The fan runs, cd spins, but no display. Held the power button without battery and power for a minute... and then tried switch it on.. still the same ... Is the mobo or video card dead.
What else can i try? How can I isolate the problem. I have opened quite a few desktops, but no exposure to opening laptops.

[ajkula66]

Welcome to the forum!

Most likely a video card BGA detaching itself from the rest of the motherboard, a well-known problem on ThinkPads from this era.

You'll need to replace the motherboard.

Good luck.

[doors666]

ok, looks like the gods are smiling at me:). I removed the hdd, memory, cd drive etc cleaned it up a bit and now the display comes up, post passes and then it gives this message and hangs - ibm hard drive active protection sensor diagnostics start..

[ajkula66]

I wouldn't get all that happy since most of the BGA failures found on these machines are intermittent by nature in early stages...

Good luck.

[wisdomkeeper]

There is a reflow guide for T4x series in the forum. Maybe it will help you. Replacement of the system board is not necessary...yet. It can be patched up using hot air gun or gas soldering iron with "torch" tip. First read the guide before you try to apply any fix or you will damage permanently your motherboard.
Here is the link to the guide - http://forum.thinkpads.com/viewtopic.php?t=57021