I love the old 100W Marshall Heads, however, The only time I'd get cranky is if someone threw it or dropped it! Especially if it's been on for even a few minutes. That said, I've never owned one, but have played through one for many years. Stuff happens, My bass case has dings all over it and it's only been in proper use for a couple of years. All of my instruments have dings in them despite being treated with kid gloves. To me, they are tools to do a job, and, as long as their ability to perform their task is not hampered......well, you get the idea. Sounds like you dodged a bullet! All the best with your search for a replacement.