Inspiron 5680, can I replace cpu fan?

Dell doesn't use standard wiring so no.  Or Dell changed back to standard.  I doubt that.  Look at the wire colors on the system fan and the cpu fan header.

FAN HEADERS

https://topics-cdn.dell.com/pdf/inspiron-5680-gaming-desktop_service-manual_en-us.pdf

They have also started making the wires all the same color (BLACK) so you cant tell how they have it setup.

If they have gone back to the

BLUE (PWM) 

YELLOW(TACH)

RED(+12v)

BLACK (GND)

then you could re wire a standard or use an adapter cable.

Three-wire fan Fan header pinouts standard

•Pin: 1  Ground  Black
•Pin: 2  12 V       Yellow
•Pin: 3  TACH     Green

Four-wire fan Fan header pinouts standard
•Pin: 1 Ground   Black
•Pin: 2  12 V       Yellow
•Pin: 3 TACH      Green
•Pin: 4 PWM     BLUE

DELL FAN WIRINGDELL FAN WIRING

Thanks for the answer. I will check my cpu wires tomorrow and attach the photo.

Hi!

My connector contains the following colors: black, red, yellow, blue. It looks like it is standard pwm connector.

Then any standard fan should work fine.  The only reason I mention this is because when they are wired the other way they don't work and worse they burn out the sensor so that you get fan failure errors and shutdown.

Ok! Thanks.