Fan problem in T20 + trying to fix

[Block3r]

After repairing the Blink of Death by a 10K resistor, new problem arose. When I start the T20, fan spins correctly - but about 10 seconds later, it stops and never starts again. I tried to fix it in various ways, but nothing worked. Additionally, I found out that it is a common problem - and it seems like there aren't any good solutions
I have an idea - soldering a +5V DC directly to the fan to make it spin all the time. Back on the sites that I found via Google, others said that it worked and spun correctly with external power supply, but when I put a +5V DC from USB cable to my fan it simply burned I'm 100% sure that I mistook one of the cables. (I checked that later on the scheme)
According to the schematic/wiring diagram I have, I had a three-cable (three-pin) fan - a Toshiba one. I purchased on the internet the four-cable one, manufactured by M a t s u s h i t a - there weren't any three-pin Toshiba editions It should arrive to me tomorrow.
The question is: where can I get +5V DC on the motherboard? Of course, I need to have a place in which is 5V all the time and no matter what does the T20 or what happens to it - the voltage never changes.

[RealBlackStuff]

Every Thinkpad only spins the fan for a few seconds at bootup, and then stops.
And only when the CPU/GPU is getting hot, will the fan start spinning again until it all cools down.
Since T20 is/was a fairly cool-running machine (provided it has decent thermal paste), its fan almost never runs.
The USB-port has +5V always on.

[Block3r]

I know it and tested it, but unfortunately after running for about an hour it never started. During this time motherboard reached ~70+ C and the PCMCIA bus was hot, I don't know how much was the CPU warmed - it doesn't have thermal sensor, but the heat sink was very hot in touch.

edit: I changed the fan and it now works properly? I don't know what to think. The old was from T22, maybe it is? Anyways, I just needed to cut out a 0,8 milimeter thick copper pad and put it between the cpu and the heatsink, to prevent the computer from shutting down.