Te 2012 iMac power on fan sound?

I get a quick power on 'click' when I first power my computer on.. It's comming from the center area.. I'm sure it's the fan powering up..
Thing is I don't think I've ever heard this before.. Or maybe I haven't noticed?
Can you hear a quick 'click' power on fan sound when you first power up the late 2012 iMac? It goes away immediately.. It's only on power up.
I have no HD, I'm using the SSD by the way. SO nothing else can be causing the sound..
-Frank

It's doing that in order to clear out residual heat and dust. Unless it doesn't return to normal, don't worry about it.

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    Paste into the Terminal window (command-V).
    The command may take a noticeable amount of time to run. Wait for a new line ending in a dollar sign (“$”) to appear.
    A TextEdit window will open with the output of the command. If the command produced no output, the window will be empty. Post the contents of the TextEdit window (not the Terminal window), if any — the text, please, not a screenshot. The title of the window doesn't matter, and you don't need to post that.

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