Lenovo ThinkSystem SR650 V2 Maintenance Manual page 110

Rear backplane: 4 x 2.5-inch SAS/SATA
The following shows the cable connections for the rear 4 x 2.5-inch SAS/SATA backplane if installed.
From
Backplane 4: SAS
Backplane 4: PWR
Connections between connectors:
Figure 44. Cable routing for the rear 4 x 2.5 SAS/SATA backplane
ThinkSystem SR650 V2Maintenance Manual
100
To
32i RAID adapter on PCIe slot 2: C3
Riser 1: PWR1, PWR2
↔ ↔ ↔
, , , ...
1 1 2 2 3 3
↔
n n