Motherboard - HP 9020 Service Manual

4-72
Assembly Access
Motherboard
1. UNPLUG COMPUTER POWER CORD FROM AC OUTLET.
2. Remove front and rear covers as previously described.
3. Remove printer, disc drive(s}, processor stack, power supply, and I/O backplane. All proce-
dures are previously provided.
4. Disconnect power cables from power supply and I/O card cage fans.
5. Disconnect disc drive cable connector(s) from motherboard connectors J53 and J54 (Figure
4-76).
6. Remove two 4-millimeter Allen screws that attach two bus bars to "H" casting (Figure 4-76).
7. Remove two #2 Pozidriv screws that attach each of the two bus bars to the chassis (Figure
4-76), and move bus bars out of the way.
8. Remove nine #2 Pozidriv screws and flat washers that attach "H" casting to base (Figure
4-76), and lift "H" casting, which includes rear grilL fans, and power supply bucket out of
chassis.
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4-MM ALLEN SCREW
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#2 POZIDRIV SCREW
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BUS BAR
Figure 4-76. Removing "H" Casting