My goodness .... okay ....
Shut the macine, UNPLUG IT FROM MAINS, open it, take away the power supply.
Look under : you will see that where the brown is on your Molex connector (its the 5V, yellow wire, uh ?
) the solder is crackeled.
Take away this solder with a solder pump, use a blade to scratch away some varnish out of the PCB to have a bigger surface of contact with the soldering, reolder the connector and use a bunch of solder. Be carefull not to put too much solder because it may get in contact with the plate when you put back the PSU in place on its bracket.
Clean the connector pins and the female one, put the PSU back in place (do'nt forget to put the voltage swich wires as well), verify whant you did, and let me know.
If you want, before doing the mod, put here a clean picture of the solering side of the connector, I will modify and put legends to it, and put it back here.