Could be a good alternative solution if your power supply failed or you need a test unit. It's easy to build with low cost, only needed a 12v Dc 3 or better 5Amp power supply and two DC-DC adjustable step-down power supply modules. These are easy and cheap to find on Aliexpress or Ebay. Some other information as testing it you can read on this post. Good luck,
A member pointed out to me that it is better to change the ground wiring in the diagram for handling the ground connection better. Therefore I also post these second version connection plan. In my view not really needed because the ground connections are already on the motherboard, and the DC modules connected to each other. But this is up to you which you prefer to use, in any case both scheme plans are usable.