Also, if you are not digging the Rev F tone, you may want to consider a recap, unless you already have. Electrolytic capacitors are only supposed to do their jobs for around 10 years, good ones of course can last 15-20 and function beyond. But the tone of a tube amp can suffer and get noisey as well. Put some nice F&T for power filtering in there at the very least, and the thing will come to life.
I recapped a Rev G (June '00) with F&T caps for filtering, and it made a big difference in dynamic response, especially when using tube rectfication. Which is why we like Rectifiers right?
If you want to keep the amp stock, Mesa will sell you the caps that are exact replacments.
In any case, you won't eaasily find amps built as well as early Mesas. They are on par with most custom builds, and can't be matched for durability, worth every penny to recap.