I have a Toshiba Satellite 5205-S506 with a bad video chip on the motherboard. It is a NVIDIA GeForce4 460 Go with 32mb video memory. There is a similar computer on eBay 5205-S703 with what seems to be the same motherboard and also the 460 Go video chip but it has 64mb video memory. Should I be able to replace my chip with the one of this other machine?

How good are you at soldering & desoldering??

If the MBoard is the same identical board other than the video then change out the board. If not then I wouldn't think that is a DIY project. You may be able to verify with Toshiba or one of their authorized repair depots.

The chip is in a socket, I should be able to pull it out with a chip puller. The other motherboard is laid out identically, but it is defective in a different way. That one apparently functions but won't power the cpu fan.

Are you sure its the video chip that's defective and that it's socketed? If so, it's probably a PLCC socket--something like this:

http://www.futurlec.com/Sockets/PLC...

Make sure you get the proper chip puller for that socket. It's real easy to break the plastic sides.

I am reasonably sure it is the video chip, I'm getting vertical lines in the display even if I disconnect the LCD and watch the video on an external display.

Now that I look at it, I may be assuming too much thinking that it can be pulled from the board without soldiering. I'm attaching a link to a picture of the chip, but I'm not sure how this site works, tell me if you can't find it. If it is a soldier job it is probably beyond me, I can soldier ac jacks and ports onto motherboards but anything with this many pins is a little intimidating.

The chip you're referring to is IC14? It's soldered and wouldn't be easy to remove without causing damage. Most motherboards can be soldered on both sides and as such solder on the bottom flows through the hole and is difficult to remove.

When I remove stuff like that from old boards I use a plumbers propane torch on the solder side. It's quick and usually doesn't damage the component but of course it ruins the motherboard.

The vertical lines could just be plain interference from a nearby magnetic or 60 hz source. It could also be bad video ram.

I guess that's not the chip, I removed the board and found the one marked nvidia on the bottom. Yes it seems to be soldiered in and little too complex for me. I will have to find a good motherboard or a machine with a good one.

Keep an eye on ebay and your local craigslist. Laptops are expensive to repair so many people don't bother. If you can find one with a wrecked screen but otherwise OK you might be able to get it cheap. I've seen some with just bad or wiped hard drives that don't get fixed.