My Serial Number?

[bep207]

I know the serial number is on the foot of iMacs
i just had my iMac repaired (logic board replaced)
now the fan runs hard all the time

i was looking through activity monitor and noticed the serial number was missing on the front page

any reasons why?
how do i fix this?

 

[WildCowboy]

Yes...the serial number disappears when the logic board is replaced. Nothing you can do about it (that I know of) except look at the printed version.