So my valvestate 100w amp has not worked for awhile...I'm pretty sure it is the preamp tube needing to be replaced (it was severely mishandled when left at a friends house). I have a limited knowledge of electronics repair, I was wondering if someone could tell me how difficult of a job this is (i.e. sensitivity, ease of serious screw ups, etc).

Also if someone has a pic of the back of a vs100r with a few instructions on the task, it would make my day.

It's really easy, you will have no problem doing it.
Current Rig:
Splawn Quickrod
Marshall 1960BX
Les Paul with Dirty Fingers
Isp Decimator
Cry Baby Wah
MXR MX108 10 Band EQ.
BBE Green Screamer
Anybody familiar with the vs100r? There is a panel covering the area which I suspect houses the preamp tube. It is covered by 4 screws which do not seem to come off, no matter how much they unscrew. IF anyone else has worked on this amp and knows how to get the panel off, I would love to know.