E–4
376220-001
Service Reference Guide, dc51000
U46
U50
U51
U52
U53
VRM controller
USB front port power switch
First USB rear port power switch
Second USB rear port power switch
Third USB rear port power switch
XBT
XMM1
XMM2 - XMM5
XU1
XU2
Battery retainer
Memory slot. DIMM1 or RIMM1 populated and tested
Following memory slots
Primary processor socket
Secondary processor socket
XU15/U15
Y1
Y2
Y3
Y4
Y5/H5
ROM socket (XU15)
Primary (TH) system clock crystal
Secondary (SMT) system clock crystal
Primary NIC clock crystal
Secondary NIC clock crystal
RTC clock crystal/tie-down
Designator
Component
(Continued)