HP 43361 manual 224

System Board and Riser Board Reference Designators

Designator	Component (Continued)
U6	Clock chip
U7	64 bit Bridge
U10	LOM1
U11	LOM1 EEPROM
U12	LOM1 PHY
U13	Audio Codec
U14	Audio amplifier
U16	LOM2
U17	LOM2 EEPROM
U18	LOM2 PHY
U19	SPI ROM - SOIC-8 footprint
U20	Fan controller
U21	SPI ROM - SO16 footprint
U29	TMDS controller
U30	Parallel port diode array
U31	First serial port transceiver
U32	Second serial port transceiver
U46	VRM controller
U50	USB front port power switch
U51	First USB rear port power switch
U52	Second USB rear port power switch
U53	Third USB rear port power switch
XBT	Battery retainer
XMM1	Memory slot. DIMM1 or RIMM1 populated and tested
XMM2 - XMM5	Following memory slots
XU1	Primary processor socket
XU2	Secondary processor socket
XU15/U15	System ROM and Socket (Socket = XU15, ROM = U15)
XU19/U19	SPI ROM and socket (XU19 = socket, U19 = SPI ROM)
Y1	Primary (TH) system clock crystal
Y2	Secondary (SMT) system clock crystal
Y3	Primary NIC clock crystal
Y4	Secondary NIC clock crystal
Y5/H5	RTC clock crystal/tie-down

E–4 433611-001 Service Reference Guide, dx7300