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Hi and welcome to JustAnswer,
Thank you for the question and your patience. Should you still need assistance for information purposes only...Initially, have you tried unplugging? ...for an extended period of time? ...and then trying using another outlet?
The described symptom and results of what has been tried would be indicative of an internal hardware issue.
If comfortably able and feel safe to do so, are you then considering a DIY (do-it-yourself) repair approach? If yes, do you have access to and familiar with a multi-meter and even perhaps a soldering iron?
Great on the DIY particularly if no longer under warranty.
Please post back with the board number of the power supply board. Additionally, please provide clear closeup pictures of this board.