First off, unless you know what you are doing, do NOT try and work on it. I don't care how old it is, the caps can retain a VERY large charge for a long damn time. I've spoken to guys who work on TV tubes who are scared of tube amps. Don't fuck around with this, it's your life.
Second off, I am an amateur when it comes to amps. Take what I say about amps with the understanding that I only kind of know what I am talking about and you should verify anything I say with someone who has a clue.
That being said, if you know which ones are the filter caps, you can drain them fairly easily. Meter for DC voltage between the positive side of the filer caps and ground. If you have any voltage, drain it by putting a lead from ground to the plate of a tube, and leaving it there for 30-60 seconds. That should make it safe, but do check, OK? Great tone is not worth dying for, after all.
So, all that safety stuff out of the way,
HERE is a PDF schematic of a GA-17rvt Scout amp. I have no idea if it is the same one or not, but there you go.
If you don't know about tube amps, then you should have already taken it to a good tech at this point, or you should go out and buy a book. I kind of think that Gerald Weber talks out of his ass sometimes (he has a tendency to claim unprovable opinions as fact, and I've seen him print a few verifiable falsehoods), but he does have a pretty good bit in his first book (A Desktop Reference to Hip Vintage Guitar Amps) about exactly this. He does not have that schematic, but he might in one of his other books (I don't have them, but you might be able to find out). But he does talk about how to go about restoring an amp. His DVD is also pretty good for learning about tube amps, but remember to take his opinions for what they are (I know amp guys who laugh at the idea that Sprague makes even a decent electrolytic cap, much less "the best caps in the world.")
The FIRST thing, after making sure it is safe, is to do a visual inspection to make sure you don't have any visibly damaged parts. The electrolytic caps are almost certainly shot, unless they have been replaced in the recent past. Look for burnt up resistors, coupling caps, and any scorching on the tube sockets (which is a sign of a shorted tube, which usually means there is some other problem which CAUSED the short). Look for rust on the transformer plates. If they are rusted, they will not work properly. With the power transformer, you won't get the necessary voltages, and with the OT you won't get all the power you should get. Smell the transformers, particularly the power transformer. If it smells burnt, it is burnt, and needs replacement. It's also not a bad idea, if you have ANY question about the components, to unsolder one end (make sure you know where they go!) and throw a meter on them to make sure they are what they say they are, and then reattach them. If that is (as I believe it should be) an old point to point amp, make sure the grounds are all good, which is to say that you have continuity between the ground terminal and the chassis. If the chassis is painted, there is a good chance that the grounds will not be good. If any of them are at ALL in question (which is to say if you have pretty much any resistance at all), then you need to either run a wire from all the grounds to a central ground point, or solder the separate ground points to the chassis (I hope you have a big fucking soldering gun, because a hobbyists 30 watter ain't gonna cut it for THAT task).
When you replace the power chord, use a three prong. I don't care if it came with a two prong, that just ain't safe, don't do it. Attach the ground (should be green in the USA) to the chassis. If the fuse is blown, there is probably a reason. Find it before you try to do anything more with the amp.
Really, don't try and do any of this until you are confidant you know what you are trying to do. These things can kill you, fast. The DC voltages in tube amps is exactly the most fatal possible level. It would actually be better if the voltage were higher, as it would just clamp down and stop your heart as opposed to sending it into fibrillation, so that higher voltages don't ruin your heart. All it takes is some CPR (usually), and your ready for a long recuperation in the hospital. With tube amp voltages, it's straight to the morgue for you (where they will cut you open for an autopsy, and if you've ever read about one of those, you do NOT want them to do that to you).
Oh, and I'm sure it goes without saying that this is not something to be done when under the influence of any mind altering substances or experiences (don't do if you've been smoking pot or your wife just left you for the pool boy).
And a few suppliers for you:
When I do amp work, I get most of my parts from one of my wholesale suppliers, which you probably can't do. But there are some good places out there.
http://www.hoffmanamps.com
http://www.tedweber.com/ (no relationship to Gerald Weber, as near as I can tell)
http://www.turretboards.com/
http://www.digikey.com/ (they carry some very nice caps, including the BC Components electrolytics in a axial package and the Panasonic E series caps, which my amp guy and semi-mentor for this shit recommended to me as the most reliable caps on the market).
http://www.mouser.com/ (great for resistors, wire, and a bunch of other shit.)
http://www.steinair.com/store.htm (actually an aircraft kit parts supplier, but they don't have a minimum order on Teflon insulated wire, and their prices for it are really good. They also are one of the few places I have found 20 awg Teflon insulated shielded wire with a Teflon jacket that is not like a light year in diameter. Cool place, and they even sent me a free tee-shirt when I ordered)
Oh yeah, and if you've never tried soldering with Teflon insulated wire, do. You'll never deliberately go back. The stuff is awesome. I don't care how long you hold your soldering iron on it, it doesn't melt. It makes the rather difficult solder joints in an amp a LOT easier. I mean, a LOT easier.
Three flippen' pages in word when I spell checked it. I've got to learn to shut my yap.
Take it all with a grain of salt. I don't really know that much about amps.
Light
"Cowards can never be moral."
M.K. Gandhi
. But at that point it will be a vintage shell with essentially all-new insides. Still cool, but not the original sound. 
