Lenovo 4228, 4223, 4229 manual Number FRU description Self-service CRU Optional-service CRU

The following table lists the major FRUs shown in Figure 3 “Locating major FRUs and CRUs” on page 57 and identifies which FRUs also are self-service CRUs or optional-service CRUs.

Notes:

•Self-service CRUs: These CRUs unplug or are secured by no more than two screws. Examples of these types of CRUs include the keyboard, the mouse, any USB device, and the power cord. Other self-service CRUs depending on product design might include memory modules, adapter cards, hard disk drives, and optical drives.

•Optional-service CRUs: These CRUs are isolated parts within the computer and are concealed by an access panel that is typically secured by more than two screws. Once the access panel is removed, the specific CRU is visible.

Number		FRU description	Self-service CRU	Optional-service CRU
		Heat sink and fan assembly	No	Yes
	1
		Internal speaker	No	Yes
	2
		Microprocessor	No	No
	3
		Optical drive (available in some models)	Yes	No
	4
		Card reader (available in some models)	Yes	No
	5
		Front audio and USB assembly	No	Yes
	6
		Front bezel	Yes	Yes
	7
		Hard disk drives	Yes	No
	8
		Hard disk drive fan assembly	Yes	No
	9
		Battery	Yes	No
	10
		Memory module	Yes	No
	11
		Peripheral Component Interconnect (PCI) card	Yes	No
	12
		retainer
		PCI card	Yes	No
	13
		Rear fan assembly	No	Yes
	14
		System board	No	No
	15
		Power supply assembly	No	No
	16
		Keyboard	Yes	No
	17
		Mouse	Yes	No
	18

Looking up FRU information

For detailed FRU information, such as the FRU part numbers and supported computer models, go to: http:/www.lenovo.com/serviceparts-lookup

Locating parts on the system board

Figure 4 “System board part locations” on page 59 shows the locations of the parts on the system board.

58ThinkStation Hardware Maintenance Manual