THis happened to me and an SE. However, it could also be much more minor and the video socket board simply fell off, or less likely the flyback cable has become disconnected.
If you are going to get into the vintage Mac business, you should either get over your fear of cracking the case and getting your hands dirty inside, or find someone who can do it for you ... otherwise this little hobby could get quite frustrating (more so than it already is anyway) and expensive. The tools are easily found at Sears and other hardware stores and a lot of support can be found here.