I just did this so I figured someone might like to know how to do it.
Basically, if one of your screens is being all glitchy and stuff, here's what you do.
You need:
One of these to open the system:
http://www.ebay.com/itm/Virtual-Boy-N64-SNES-Extra-Long-Tempered-Steel-Bit-/280719703930?pt=LH_DefaultDomain_0&hash=item415c32bf7a#ht_1222wt_522 (normal-sized bits are too short, derp)
A super small philips screwdriver
An oven
First test to make sure you're taking out the right display. Mine was the left display.
Second, open the thing up. This is kinda hard, even with the proper bit, because those screws are REALLY deep. Just keep trying, you'll know it worked when it does a clicking sound. I forgot taking a picture of this because I'm dumb, but the 4 screws that are around the cartridge slot that aren't deep at all don't need to be taken out, only the ones that are in deep holes. May take a few minutes just to take them all out, but eventually it works.
There's the thingy that connects to the display:
You gotta use a small philips screwdriver to unscrew the thingy (yay for scientific terms), just the small screws, the bigger ones should stay there. Once that's done, you have to disconnect the cable from the connector, which is a bit tough, just be careful and you'll be fine. Then, put it in a piece of aluminium foil as so (with the sort of plastic protective thing on the board pointing up):
Preheat your oven to 200 degrees F, and, once that's done, put the thing in the oven!
Sounds weird, but whatever! Leave the thing in the oven for about 2 minutes, maybe a bit less (so precise!). Take it out and apply pressure on the cable, rub it, whatever, to ensure that the connection gets more solid. Once it cools down, I've seen people suggest to put tape on the cable, so I did that too.
And then put it all back together! Careful when connecting the display thingy back in, it's kinda tough since it's so small and you have very little space to work in.
And voilà, you fixed your Virtual Boy by putting part of it in the oven! I only put it a minute, and it's not perfect right now but it's actually playable so I'm pretty sure I'll be putting it in the oven again soon to finish up the repair. But yeah, if you were skeptical about that method, it actually does work.
