If 10a-ps3.B was first to drop check the status of the supplies for the quench protection switches through the RHIC>PostMortem>Quench>Delayed 25 minutes>qpswCtrl PET page. The only listed statuses should be "No Quench Link, Open Contactor, Remote On".
If 4b-time.B was the first to drop check the status of the main magent power supplies through the RHIC/PostMortem/Quench/Delayed25Seconds/MainMagControl_4b-ps4 PET page. The only listed statuses (at the bottom of the page under mainpmctrl) should be "Off-fault, Ctrl Pwr On, PS Remote, Reg Remote, Fault, Contactor".
Otherwise go here. to eliminate or identify likely causes.