How does a preamp die from sitting unused for a few months?

I’ve got an Inspire pre that I generally use with an Inspire amp.  I’ve been using the amp with a Cary pre but decided to put the Inspire in its place .

Installed, plugged in, turned on…and nada.  Tried different power cable, different outlet and still nothing.  Checked fuse and it’s fine.

Tried wriggling the PC and nothing.

I took the tubes out and will look into it later today but I find it weird that a piece of stereo equipment dies from sitting unused for a few months.  

Any idea what could have caused this?  Maybe a wire came loose?

Thanks.