No Power to T42 Motherboard

[the1sam]

Hello,

I recently got a Fan Error on boot. I removed the fan to test it independently with a 5v source, verified that it was dead, and replaced it with a new working fan. However, when I attempted to boot again, I got the same Fan Error.

Removing the new fan, I found that the motherboard was now not supplying the fan with the required 5v. In a frustrated late night attempt to boot and salvage some data I connected the new fan, powered it, and booted the laptop which ran for about 5 or 10 minutes before shutting off. I was able to still see the power indicator when plugged into the AC adapter, and left it for the morning...

Now I am finding that no power is being supplied to the motherboard at all! When I measure the power at the AC adapter it shows the normal 16 VDC but when plugged into the motherboard it only reads about 1 VDC and the power/charging indicator is not illuminated...

Can a busted fan controller (MAX 1845) short out the entire board?
Is this possibly a common symptom of some other problem?

Thanks for any insight/tips!

[jimmy274]

No, but maybe an overheated CPU can short a trace or two, but I doubt it. Maybe you just have a blown fuse (or two), or some of the NMOS transistors providing power to the mainboard (TPC8014, TPC8109 or TPC8111) are fried - my problem...

[the1sam]

Thanks Jimmy...I gave my Mobo the once over about 100 times this evening. I located and continuity tested all the fuses and transistors and they all look fine and have the proper connectivity. From an EE standpoint it is still mystifying me that when the 16v power is attached to the Mobo it only measures at 1-2 Volts. I also listened closely and heard one of the round M53s (i think) ticking...

Could there be some voltage regulator that is causing such a voltage drop?
If there was a short or something was grounding out, I would get 0v instead of 1 - 2v right?
Any ideas? anybody?