HP Elitebook 840 G1 Motherboard Replacement - iFixit Repair Guide
747072-001 HP System Board (Motherboard) With Intel Core i5-4200U Processor for EliteBook 840 G1
802523-001 730810-001 For HP EliteBook 840 G1 850 G1 Laptop Motherboard 6050A2560201-MB-A03 With I7-4500U I7-4600U 100% Test OK International Power Cords - Newegg.com