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

I'm guessing danager is probably right.  😉

I only visually checked the fuse and didn't do a continuity test with the power cord connector.  I'll try those next.

None of the tubes turn on.  I'm leaning toward the toggle power switch gave out as there is nothing remotely loose or broken off inside.  DHad does some great work!

If the rectifier tube is burned out would the rest of the tubes and power indicator light light up, or would all electricity be stopped at the first tube (here I'm assuming the rectifier is the first tube)?

Thanks, all.

+1 @gs5556  .  Always ohm the fuse out.

I'm guessing the power switch or the rectifier.  If there is a big capacitive element in the power supply there can be a pretty severe shock to the system when first turned on.

My Lab12 Integre blew its fuse twice already, and I can assure you when I took out the damaged fuses there was no visual indication whatsoever on the damaged fuses. That's why it's handy to keep spare fuses around. 

How old is the preamp in question? Look for any caps that might be pooched or leaking. Double check the fuse. I’ve had some blow where it took a magnifying glass to see the break. While you have the magnifying glass out look at the pc boards for any burns or breaks.

All the best.