There's a couple of steps that you can do to fix a bad Xbox One PSU.

1. Ventilate the PSU. 

   Put the PSU away from sources of direct heat like radiator, oven, furnace, amplifier, or heat register. If placed near a heat source, the PSU can easily get too hot and cause components to melt or get damaged.Clean the PSU of dust as its thermal performance can dramatically decrease if there’s too much dust on it. Then, make sure that the PSU is allowed to cool off if it has become way too warm to touch.NOTE: The PSU can become warm even when working normally. However, if it has become abnormally hot to touch, or if it smells of burning plastic, make sure to unplug it from the power outlet and the console right away.

2. <strong>Reset the PSU.</strong>

   If your Xbox One console is not working or if you suspect that there’s an issue with the PSU, it’s a good idea to reset the PSU. How to reset an original Xbox One PSU. -Turn off the Xbox One console and unplug the power cable from the Xbox and wall outlet. -Wait for 10 seconds to allow the PSU to reset. -Afterwards, connect the power cable to the wall outlet but NOT to the console yet. -Check the PSU light or LED If the LED on the PSU turns on, connect the other end of the power cable from the PSU to the console but do not turn the console on yet. There are two situations that can happen after this:the Xbox One console turns back on,the Xbox One console won’t turn on but PSU LED is ON, orthe PSU LED won’t turn off or blinking.Xbox One console won’t turn on but PSU LED is ONIf this is the situation on your end, check the LED on the PSU again. If the LED is still ON on the PSU (after connecting the power cable to the console), turn the console back on by pressing the Xbox button in front. If the console turns on, then you may have fixed your issue.If the console won’t turn on but the PSU LED is still ON, then you have an issue with your Xbox One console and NOT with the PSU. Replacing the PSU at this point is useless. You need to have the console repaired instead. PSU LED won’t turn off or blinkingIf the PSU light turns off or remains blinking when you connect the console after a PSU reset, that’s a PSU problem. You need to have the PSU replaced as the console is most probably okay. You can contact Microsoft so they can let you buy a PSU. NOTE: At the time of this writing, the Xbox One is no longer being manufactured so you’ll most likely end up getting a new Xbox One since Microsoft no longer offers their official repair for it. If you know a third party shop that may help, bring the console to them.How to reset a Xbox One X or S PSU. The Xbox One S or X models have internal PSU. If the console is not turning on or keeps restarting on its own, you may need to reset the PSU to fix it. This can happen especially if there’s a power surge recently.To reset an Xbox One X or S PSU:-Unplug the power cord from the console.-Wait 10 seconds.-Plug the cord back into the console, and then press the Xbox button  on the front of the console.If the console turns on, the internal power reset worked. Do this step if the problem happens again.