T41 Fan Error

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screwdriver · #1 Post by **screwdriver** » Mon May 05, 2008 3:50 pm

hello,
I was running my thinkpad when I felt it was getting abnormal warm.
the temperature was about 60°C so I turned it off (no reaction when using tpfcontrol).
since then it reports fan error on startup...
I've tried 3 different (working) fans and already changed the cmos-battery.
what else can be the problem?

thank you

makai · #2 Post by **makai** » Mon May 05, 2008 7:31 pm

Motherboard +5v regulator.
Fan Temp sensing circuit.

Whatever the cause, it sounds like a motherboard problem. The fan is supposed to spin up for a short time while booting so it's not OS dependant. If the laptop in still under warranty, I would give Lenovo a call.

screwdriver · #3 Post by **screwdriver** » Tue May 06, 2008 1:57 am

no warranty so I'd be glad to fix it myself.
is that possible in any way or no chance for me?

Brad · #4 Post by **Brad** » Tue May 06, 2008 2:12 am

Unfortunately from your description it sounds like replacing the motherboard is your only fix.

Brad

screwdriver · #5 Post by **screwdriver** » Tue May 06, 2008 1:11 pm

****
how does that come? was it caused by user-faults or is it a known issue?

Sveat · #6 Post by **Sveat** » Thu May 08, 2008 1:32 am

makai wrote:Motherboard +5v regulator.
Fan Temp sensing circuit.

Whatever the cause, it sounds like a motherboard problem. The fan is supposed to spin up for a short time while booting so it's not OS dependant. If the laptop in still under warranty, I would give Lenovo a call.

But do you know where is Motherboard +5v regulator for the fan?
http://sveat.c7obs.net/t40-120.jpg
http://sveat.c7obs.net/t40-091.jpg
http://sveat.c7obs.net/t40-084.jpg
http://sveat.c7obs.net/PB288385.JPG
http://sveat.c7obs.net/PB288388.JPG

I think it's one transistor

makai · #7 Post by **makai** » Thu May 08, 2008 2:19 am

It could be a transistor, a diode, a voltage regulator, a capacitor, or one of the fuses I've read so much about in this forum... basically anything. Lenovo/IBM will not divulge schematics due to proprietary info, so you're out of luck there. Problems like these are troubleshot using test equipment and reverse engineering. A lot can be found with just an ohmmeter by comparing like components on the board.

To answer your question, no, I don't know where the fan gets the +5 volts from. It could also be something in the temp regulator circuit. Maybe some thermal device just shorted or opened up. Best advice is take an ohmmeter and start tracing the fan leads, then compare devices. Next best thing is pay someone to look at it, thirdly... buy a new motherboard.

Sorry, I know that doesn't help you. Good luck.

makai

T41 Fan Error

T41 Fan Error

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