Original Xbox FAQ
The original Xbox power button isn't working, what's wrong?
Starting with the easy stuff
First We will start with the easiest and cheapest thing you can check. The power button may not be working because, well, because the power button PCB may be broken! If you remove the faceplate of the original Xbox you can see a small PCB (Printed circuit board) mounted where the buttons are. Sometimes the wires can get corroded, sometimes the power button isn't working for a lot of reasons. Luckily it is easy to replace and should probably be the first place you start. If you have a spare one or a second original Xbox, switch out these PCB's and see if that fixes your issue. If you don't have an extra they are pretty cheap. You can find a Original Xbox power button here! If you try this and still have the same issue, then we need to move on to the next possibilities.
Could be the power itself!
Just because the power button isn't working, doesn't always mean it's the button. It could be an issue with the power of the console itself. This is a little more complicated an issue, as having no power to the console could be two different problems. You could have bad capacitors on the motherboard, or the power supply could be bad too. I actually wrote an entire article on how to check these issues as well as a step by step run down to diagnose which of those it might be. You can see the article on an Original Xbox that won't turn on here. That article can help you check to see if that is the problem. However, that's not the last reason your Original Xbox power button isn't working. If you checked that out and still have no results, then you'll want to return here to read the final steps you can take.
A major hardware failure
This one may surprise you, if you went through everything thus far with no results then your original Xbox power button isn't working because of a major hardware failure that causes damage to your motherboard. We are talking about the notorious leaking clock cap issue. The clock cap is another issue I wrote an entire article on, so I won't dig deep into that here. To make a long story short, a capacitor on the motherboard begins leaking onto the motherboard itself. This leakage causes traces to slowly corrupt and decay. Once that damage occurs you don't have many options left. You could technically hand solder a wire on each start and end end point of that trace to bypass it. However there could be dozens of traces effected by this and it is an extremely difficult task. Your last real option would be replacing the motherboard with a working motherboard / HDD set. You can find an original Xbox motherboard here!
