How to fix a black screen when fan is running then stopping frequently

Hi @alertmrcrazy100

Sounds like the laptop is not even starting and passing POST (power on self test). To prove this try connecting an external monitor (TV?) to the laptop's HDMI port and check for a display on it from the laptop. Press the Fn + F8 keys (both together) to toggle between the laptop screen only, the external display only or both on together.

If there's no display on the external monitor also, try a full power refresh in case it is a corrupted BIOS and check if that resolves the problem.

Here’s the procedure:

a). Disconnect the charger from the laptop if connected.

b). Remove the main battery from the laptop.

c). Remove the RTC battery from the motherboard.

Here’s and image taken from Step.23 of the ifixit Asus U50F-RBBAG05 Motherboard Replacement guide that may help

(click on image)

When the battery is removed measure its voltage. If it is <2.6V DC replace it. Usually it is a CR2032 Lithium coin cell battery that is available most everywhere e.g. supermarkets. The battery model number is printed on the battery itself if you wish to confirm.

d.) Reinsert the RTC battery (or its replacement). (+ve on top as marked on the battery)

e). Reverse the above to re-assemble the laptop.

f.) When the laptop is completely re-assembled, connect the charger and try to turn on the laptop.

If it starts OK there may be a message about the date and time being incorrect. This is normal as the BIOS has been completely reset back to its default settings. Once the date and time have been adjusted the message won’t appear the next time that the laptop is started.

If you had previously changed any user defined settings in BIOS to suit whatever specific hardware configuration that you had for the laptop, then these will have to be set again.