Hey Cliff, hope it's just new tubes you need, SS wouldn't work if no power but the tubes also need heater filament power (MJMPs territory, possible transformer problem ?). Unusual for tubes just to not work, they tend to degrade (slowly) but generally just sound more shabby (though they can just not work, but both of them ?? and if so why ??).
The 2.01 is the last EPROM upgrade so your on the latest version. If you are going for a new transformer, the MDRT is a good idea, while it's more expensive it's a good and worth while mod (http://www.marshalljmpmodshop.net/miscellaneous_parts_and_replacement_tubes.htm).
Do the tubes light up/glow when you power it on ??, if so there may be a different problem.
It will probably need new tubes though regardless, many choices and good discussion elsewhere on the depot, for MP1 I'd go with low noise high gain JJs (http://www.dougstubes.com/preamp-tubes/12ax7-ecc83-7025/jj-ecc83.html) or short plate Mullards (http://www.dougstubes.com/preamp-tubes/12ax7-ecc83-7025/mullard-cv4004-12ax7.html), the Mullards are a more 3D tube IMHO, but very subjective area tube choice.
Any way for $50 you've bought one of the best tube preamps ever made and definitely worth getting it going.
Cheers Richard