Service manual

Troubleshooting 3-81
Despite the hang in the two QBBs, power-up continues on the CSB.
The PCI box with the standard I/O module is not connected through the
QBB backplane IOP – local I/O riser – near end mini link – hose – far end
mini link – PCA remote I/O riser – PCI backplane to the standard I/O
module.
The same condition is seen during the remaining phases of power-up.
The power on summary shows a failure on each CPU in the system.
The main clue in troubleshooting this event is noting what the machine was
doing at the time of the failure. In this case we know the failing test is 1b, sub-
test 19. From Appendix C you can determine that Test 1b, Local IOP
Configuration, hung during subtest 19, probing PCI Bus 0 on each “good” hose
looking for a STD I/O module. This knowledge might lead you to suspect a
problem with the backplane, IOA or IOD, or the MPLL associated with either of
those ASICs.