IBM THINKCENTRE 8141 - Manual (Page 25)

5. Reconnect the external cables and power cords to the computer.
1 PCI slots 9 Diagnostic LEDs
2 PCI Express (x1) slot 10 Power connector
3 PCI Express (x16) graphics slot 11 Audio line out connector
4 Ethernet connector 12 Audio line in connector
5 USB connectors 13 VGA monitor connector
6 Mouse connector 14 Serial connector
7 Parallel connector 15 Keyboard connector
8 Serial connector (some models) 16 USB connectors
6. If a cover lock is installed, lock the cover.
Replacing customer replaceable units (CRUs) 17