IBM THINKCENTER 8189 - Manual (Page 40)

Locating components
Types 8185, 8186, 8192, 8413, and 8430
The following illustration will help you locate the various components in the
computer.
1 Power supply 5 Memory connector
2 PCI adapter connector 6 Hard disk drive
3 AGP adapter connector 7 Optical drive
4 Support bar 8 Diskette drive
34 Hardware Maintenance Manual