on a serious note... couldnt it be that its metal stretching / creeking against each other from temp variances?
You know, like the tick sounds you get when a car has been shut off from being on for a while?
i always thought it was due to some mechanical temp sensor
u know when they layer 2 metals together and 1 shrinks/expands more than the other.
anyway it's possible but seller says there's no such noise frm it when he had it.
i intend to cut the side panel to add a plastic window so i can monitor it closely.
