LAPTOP: stays powered on for only 3 seconds.

[downward spiral]

The Idea
Yesterday I came up with the bright idea of painting the palmrest of my laptop.  It was beginning to look rather ugly from heavy usage and my mouse burning the plastic. Please note, this laptop worked fine before I took it apart.

The Disassembly/Reassembly
I started to disassemble the machine piece by piece using some very nice directions I found online: Link - http://www.irisvista.com/tech/laptops/ToshibaM45/Satellite_M45_disassembly_1.htm. My goal was to get this one piece of plastic separate from everything else so I could just spray paint it, so I removed the keyboard, removed the LCD, removed just about everything except for the motherboard (I skipped the part where it said to remove the heat sync because I didn't feel like redoing the thermal compound) until I just said "forget this" and decided to put it all back together. After reassembly I plugged the laptop back in and pressed the power button. The button light came on, the fan spun, the HD spun, everything seemed fine for about 2 seconds: Then it shut down. Now, this is where I have been for the past 24 hours. (note: The LCD gives no sign that it has powered up) In this time I have tried narrowing down what could possibly be the problem here.

So far I have done the following things...
- removed the HD and tried to power on, same results.
- removed both memory cards, swapped their positions, tried one at a time, all with the same results.
- reseated every connection that I removed during my initial disassembly, same results.
- tried to power it on with/without the battery, same results.
- disconnected the touch pad, usb ports, Ethernet ports, keyboard, LCD, each one at a time, same results.
- tried powering on with/without the DVDRW drive installed, same results.
- I did one final test where I unplugged absolutely everything (all ports, devices, keyboard/touchpad, display, etc.) eliminating any chance that it was one of these items causing this malfunction, in hope that maybe it would go to the bios (even though I would have no display), same result.

I read somewhere that a guy had a similar problem because of a bad LCD connection, so I took apart the flip top portion of the laptop and inspected the connector behind the actual screen, everything looks fine. I even went as far as disconnecting the heat sync, which I HATE doing, cleaning off the old compound, and adding new, same result.

In Conclusion...
I am beyond frustrated with this thing right now.  I have built my own desktops in the past and consider myself fairly knowledgeable in computer hardware/software. I have tried everything I can think of at this point and am begging for advice. I called Toshiba's technical support line where I was reminded my laptop went out of warranty status last December and it would now cost me $425 to have it looked at. "Yeah Right," I said. I could probably find the same machine on ebay for less than that. Thanks in advance for all help.

Laptop Specs:
Toshiba Satellite M45-S2653
1.6GHz Intel Pentium M
Windows XP
512MB RAM (factory) plus 1GB RAM (upgraded)
80GB HD

Manufacturer's Description:
Microsoft® Windows® XP Home Edition, Intel Pentium® M Processor 730, 512MB DDR SDRAM, 80GB (5400RPM PATA), DVD SuperMulti (+/-R double layer), 15.4” TruBrite™ widescreen WXGA, Intel Graphics Media Accelerator 900, Intel® PRO/Wireless 2200BG, CD control buttons, IEEE® 1394, 6-in-1 Bridge Media Adapter, Express Media Player, 1 year limited warranty

Thanks,
Downward Spiral

[matt]

I'm sure this is going to sound obvious, but I would triple check and make sure you have everything reconnected correctly.  I would go though the guild again making sure everything that got disconnected got reconnected.  I would also check for any forms of damage.  Check for any loose screws or anything else that might be shorting something out.  Also make sure its plugged into the power.  My laptop will only power on for a second or two if the battery is dead.

Like I said, I'm sure you've checked this, but another look never hurts.

[downward spiral]

I took it apart again, this time all the way. I separated absolutely everything from the motherboard except for the power switch which is connected with a ribbon cable, plugged the power cord into the port which is soldered correctly to motherboard leads, and pressed POWER... same result! It turns on for 3 seconds, then light goes back out. It MUST be something soldered onto the motherboard because everything else has been ruled out. If I can't find a cheap motherboard I guess this is a good excuse to get a new laptop

[patio]

I s it possible one of those tiny screws has fallen into the cas and is shorting out the MBoard or a component ? ?

[downward spiral]

Not possible. I had the motherboard by itself, out of the case, with only the power switch and power hooked up to it. I even tried without the processor.  it is definitely either something in the power switch or the motherboard.

[downward spiral]

Does anyone know what swtich S1 does on this motherboard? It doesn't appear to do anything, though I could be doing something wrong