Lenovo T510 Fan error

[basskilla]

Hi there!

I have a Lenovo T510 with a Fan error message on the startup.

I have found this forum,It say fuse F13 is the problem,near the fan :

https://forums.lenovo.com/t5/ThinkPa...r/td-p/3548532



I measured it,and that was wrong,and I replaced it.

Now the fan is spinning in the start,but after a few sec, it is stopped,and the same fan error message again.

I cleaned up the fan,and I replaced it with a temporary test fan,same result.

I have the schematic,what I attached,but I can't figure out what is the problem.

If You have some idea please help to me!


Thank You!

Best wishes!

[SMDFlea]

Re: Lenovo T510 Fan error

Try to resolder the 6 pins of U45 , use plenty of flux.

[basskilla]

Re: Lenovo T510 Fan error

Try to resolder the 6 pins of U45 , use plenty of flux.

Thank You,I tried it but nothing changed.

I have a donor motherboard with the same U45 chip.
If I swap those chips,can that solve this fan error problem?

[SMDFlea]

Re: Lenovo T510 Fan error

Try it

[R_J]

Re: Lenovo T510 Fan error

Do you have the FAN_ON signal? I assume it is a pwm signal to drive the fan at different speeds

[SMDFlea]

Re: Lenovo T510 Fan error

FAN_ON into Q21

[sicilianul]

Re: Lenovo T510 Fan error

Hello. Same problem here. I have 5v FAN_ON on q21, VDD_FAN and FAN_FRQ all for 1 sec. Any ideas ?

[sicilianul]

Re: Lenovo T510 Fan error

Hello. Same problem here. I have 5v FAN_ON on q21, VDD_FAN and FAN_FRQ all for 1 sec. Any ideas ?

LE: My problem was Q20. Removed. Made a short between B + C. Replaced the FAN. Everything is fine now.

.

[m.ksy]

Re: Lenovo T510 Fan error

LE: My problem was Q20. Removed. Made a short between B + C. Replaced the FAN. Everything is fine now.

.

thanks!
also helped in my case with w510

[fester]

Re: Lenovo T510 Fan error

The same problem ,shorting B anc C of Q20 helped. This new ordered fan have probably another output section for rpm sensing. thanks

[Askic]

Re: Lenovo T510 Fan error

Wait the sec. If you remove Q20 and short B and C, then, this part of t ecircuit will become a voltage divider. That means that FAN speed will become constant. There will be no way to control the speed. Maybe this will be sufficient for the most time, but overheating is possible.

[MIGUELIX]

Re: Lenovo T510 Fan error

Hi , i have same problem , a seller ask me , those boards , check the fan , but i read only a peak of volt and after immediately "Fan error " , i don't think are the fan , anyone have tried to put another fan before working around the Q20 transistor ?? Thanks for your help . Miguelix

[mon2]

Re: Lenovo T510 Fan error

See attached.

Measure the voltage output of the 3v3 TACH feedback @ Q21. Do not bypass this transistor else you risk to damage other parts on your logic board.

Without the use of Q21, the voltage output from the FAN is not limited - it can swing to a dangerous value and kill the digital feedback pins used to monitor the FAN operation.

Post the voltage at each leg of the circuit to review.

[ktmmotocross]

Re: Lenovo T510 Fan error

what is signal TACH from FAN? pulse or analog? im to lazy to check with scope if somebody know it

[mon2]

Re: Lenovo T510 Fan error

See attached. (borrowed without permission from another website)

The output is apparently open-drain so there is a low signal but no HIGH signal - instead, the transistor is OPEN and the internal pull-up will define the 'soft high voltage'.

On this note, only 5v is being fed into the fan connector so very likely the pulse stream output swing (hall effect switch will trigger upon each revolution of the fan) will be 0 to 5v which is too high for digital logic to accept without damage.

Respectively, Q21 will perform this level shifting to the 0 to 3v safe levels.