Technical data

3-14 Power Subsystem
See Figure 3-13 for the power-enable/power-ok signal timing. Note that the enable signals
are PENx (TTL_H), and that the fault signals are POKx (TTL_L).
Figure 3-13 Power-On Signal Timing
Note: The POKx signals (with the exception of POKE) remain high unless there is a
fault. The System Controller checks for a low TTL signal to indicate a failed
POK problem.
3.3.1 Isolating Errors
With the key switch in the Manager position, the voltage status menu can be called up on
the Status Panel. This menu displays the actual voltages at the midplane/backplane, at the
power boards, and at the VCAM. The voltage status menu is shown in .
Figure 3-14 System Controller Voltage Status Menu
If an out-of-range voltage level is sensed on either the midplane/backplane, 505, or 512
power boards, the System Controller will display a message indicating which voltage is
out-of-range and whether it is high or low. The display indicates which voltage level failed,
but cannot isolate the failure to an individual power board because same-level voltages are
ganged together.
The power-OK (POK) signals also cannot isolate a voltage fault to a specific component.
The voltages at each power brick are monitored, but the power-OK lines (POKA, B, C...) are
48V
V5_AUX
PENA
POKA_0D
PENB
POKB_0D
PENC
POKC_0D
PEND
POKD_0D
PENE
PENE_0D
49 12.3 49
1.60 −6.3 −12.5
OLS
512 Board
512/505 Board
System Controller
IO4−VCAM