3-18
Computer Group Literature Center Web Site
Functional Description
3
❏
BFL
(DS1, yellow). Board Failure; lights when the
BRDFAIL
∗
signal
line is active.
❏
CPU
(DS2, green). CPU activity; lights when the
DBB
∗
(Data Bus
Busy) signal line on the processor bus is active.
❏
PCI
(DS4, green). PCI activity; lights when the
IRDY
∗
(Initiator
Ready) signal line on the PCI bus is active. This indicates that the
local PCI bus is active.
❏
CPCI
(DS3, green). CPCI activity; lights when the
IRDY
(Initiator
Ready) signal line on the CPCI bus is active. This indicates that the
CPCI bus is active.
Fuses and Polyswitches (Resettable Fuses)
The MCP750 provides inline slow-blow fuses for each power rail
inc5Vdc, +3.3Vdc, and PMC +5Vdc. Polyswitches are provided
for VIO, keyboard/mouse Vcc, and the two USB output voltages, +12Vdc
and -12Vdc. The
Table 3-3
lists the fuses with the voltages they protect.
Table 3-3. Fuse Assignments
Fuse#
Type
Voltage/Purpose/J Number
Fuse
Rating
F1*
Slow
Blow
+3.3Vdc for onboard voltage, to J12 PMC connector
and to J3/J4 Transition module connectors
5A
F2*
Slow
Blow
+5Vdc for onboard voltage and to J3/J4/J5 Transition
module connectors
5A
F3*
Slow
Blow
+5Vdc to J11/J13 PMC connectors
2.5A
R18
Poly-
switch
+5Vdc to J5 Transition module connector for
keyboard/mouse voltage
1.1A
R20
Poly-
switch
+12Vdc to J12 PMC connector and J3 Transition
module connector
2A