First of all, I would be less concerned about your amp and more concerned with electrocuting yourself silly if you open it up and start poking around inside. The filter capacitors hold large charges for long periods of time, and if you're not careful, you could end up discharging them through your body. There are several ways of discharging the capacitors. I usually do all of them just to make sure everything's safe. Here's how I do it:
1. Let the amp warm up in standby for a few minutes, then turn it on and start playing. As you're playing, unplug the amp from the wall, and keep strumming as the sound fades out. This will drop the voltages below a lethal level.
2. Next, construct a probe with an alligator clip on one end and a multimeter probe on the other. Cut the cable in half, and solder in a 150 ohm 10 watt resistor. Clip the alligator clip to either the chasis or the central ground point, and touch both sides of all the filter capacitors using the probe end.
3. Once you're sure you've got all the filter caps, touch all the tube pin sockets on one preamp tube and one power tube. I recommend touching all the pin sockets, because I can't remember which one is the correct one to touch, and it varies depending on the type of tube.
After all this, you can safely open up the amp.
Ryan