Epson EQUITY 386SX/16 PLUS - Manual (Page 118)

2. Hold up the front of the subassembly at a slight angle
and arrange the ribbon cables so they curve underneath
the subassembly and extend out its left side. Then grasp
the two power supply cables, labeled P4 and P5. Each
connector has six pin holes and a large tab on one side,
as shown below.
There is one 12-pin power supply socket on the right side
of the main system board (toward the back) that holds
both of the power supply connectors, as shown below.
power supply socket
5-34 Installing and Removing Options