Lenovo T61 Fan working, Q81 makes FAN_FRQ signal, but system still show FAN ERROR

[ktmmotocross]

Hello.
Have this old Lenovo T61 that shows FAN ERROR, but Fan working, sensing works, Q81 makes FAN_FRQ signal, but system still show FAN ERROR

any hint?

[usyusy]

Re: Lenovo T61 Fan working, Q81 makes FAN_FRQ signal, but system still show FAN ERROR

is FAN_FRQ (Fantech) reaching on SIO?

[ktmmotocross]

Re: Lenovo T61 Fan working, Q81 makes FAN_FRQ signal, but system still show FAN ERROR

maybe i was wrong about that fan is ok.

I have nice square signal , but after few seconds signal from fan start to be very distorted. it think that signal from fan is bad but can be that distortion made by transistor Q81 ? signal come to base so i dont think but....

[ktmmotocross]

Re: Lenovo T61 Fan working, Q81 makes FAN_FRQ signal, but system still show FAN ERROR

after fan replace everything is ok, so it was bad TACH circuit in fan