Hello. I have been trying desperately to fix my xbox after the dashboard failed on me. I was getting an error 21 until today, so I decided to try and hotswap it. After many bad tries, I tried a different tutorial, where you unplugged the DVD drive. However, when I went to do that, a large spark came out of my xbox from the middle of nowhere, and it no longer powers up. I was wondering if it is possible to still get it up and running games (like it still did) with an external source of power, or if it was possible to use my other xbox to repair it.
There is a way to do this with an old ATX PSU.... But it's long, requires a lot of knowledge, and some parts that you may not have. You may be much better off getting a replacement PSU for your system www.llama.com/xbox/repairs/repairs.htm