C655 Won't boot

I have a Toshiba Satellite C655-S5113 (PSC12U-02V01V) laptop which my Dad asked me to fix. When I first got it it would not boot. I disassembled the bottom half to mainboard level, cleaned out a significant amount of dust/dirt, carefully reassembled, and it booted up great. About 1 minute to the Win7 "chime" sound coming out of the speakers, but video was badly misaligned and vague shape-blocks were visible. It kind of looked like the color banding of a kaleidoscope to me. Anyway, not at all usable.

I pulled the screen and ordered another B156XW01 v.2 from Amazon, installed it, and now it won't boot at all. I don't understand why it was booting with bad graphics, but with this new screen I'm back to square one. I was careful to make sure all the wires surrounding the screen (WiFi antenna?) were still in the little precut chases and not pinched by my screws.

I'm not sure if it's related, but Dad ran this C655 for a year on an underpowered power brick. It was consistently delivering 4A/90W power, where the OEM PA3717U-1ACA PSU is 19V/6.3A/120W. It's running on a genuine Toshiba PSU now, but the place that the plug goes in wiggles a lot. Gently holding it in the various directions it will travel doesn't seem to make a difference, and plug holding was not needed when we got Windows to boot with bad video.

Do I need to go pay a $70 diagnostic fee to my local computer shop to figure out what I've screwed up? Or is this C655 a junker and I should get Dad another $300 machine?

 

Could be the GPU. I'm going to assume it's the intel IGP, and if it is then why not try swapping the CPU (if you have a compatible one), since the GPU is on the same chip as the CPU.

Also try one ram stick at a time, could be bad ram?

Probably not, but worth a try.

 

as above, sounds to me like kippered video card which is integral to the motherboard in that model i believe (not the CPU, i believe its only in the core i series cpu's that intel started putting the graphics into the cpu package itself)

so basically its new PC time unless the swap out of the ram works, but to me it does not sound like a ram issue

 

It has a newer CPU (Arrandale, the p6100 is like a version of the first gen core i CPU, but celeron version):
http://us.toshiba.com/computers/laptops/satellite/C650/C655-S5113/
http://ark.intel.com/products/50175/Intel-Pentium-Processor-P6100-(3M-Cache-2_00-GHz)

 

ah fair enough, shot cpu then!

 

Tried swapping the ram sticks (it has 2x2GB, both are removable) in one at a time, with and without battery each time, nothing's happening. I don't hear the HDD engage (though it's so quiet I may just be missing it), but leaving it running 2M each time I never get the Win7 chime as before.

I don't have any extra hardware, other than the bad PSU brick and the screen (which I suspect is still good). What's the best CPU I can drop into this box? Do you use Acrtic Silver-style thermal paste on the top of the CPU, below that X-looking cover? Please forgive my noobness, I normally work on desktops.

 

I don't think you should spend money on the best CPU available because there is a chance that the CPU isn't the problem.
I would get another cheap celeron if you want to diagnose the notebook.
Or as you said before, just buy another $300 notebook and sell you broken one on eBay.

 

Thanks for the advice Moral! I bought the same CPU (used) off eBay for $9, when it gets here I'll plug it in and we'll see what happens. If it doesn't work, we're only out $9 and I have extra Arctic Silver bottles already!