I’m taking a look at an Xbox one for a friend that won’t power on. The power supply brick is outputting 5v and, after coming across the standby voltages image, I started probing around to see what may be missing. I noticed that, at a minimum, I am missing 5v to some parts of the board. I think I have narrowed it down to something being bad in with U4B4. There are 4 pins on one side of the component that are supposed to be getting 5v (I marked U4B4 in the link) which aren’t, and after that the 4 resistors above it are supposed to be getting 5v. However, on the other side of U4B4, the second pin from the right is supposed to be getting 5v, which it is, but so is the pin on the far right which is not marked as something that is supposed to have 5v in the diagram (to be fair it isn’t marked at all).
What exactly is U4B4 and should that pin on bottom right also be getting 5v?
Link to the part of the standby voltages page with U4B4 marked:
Link to the standby voltages page: