I find that about 20% of the stuff I try to repair I just make worse and end up throwing it in the garbage. The reason in every case is down to ham-fistedness and carelessness. Fortunately I don't do this for a living and none of the stuff that blows up belongs to anyone else. Funny thing is, you'd expect to get better over time with this activity, but I haven't. My kill rate remains at one in five and there doesn't seem to be anything I can do about it.The other day I had a vintage tape recorder burst into flames because I forgot to discharge an electrolytic cap that I'd diligently re-formed before fitting it. It brushed against something it shouldn't have done in the process and *bang!* another one went west. Sigh...