Internet Router Hardware Guide

Troubleshooting Hardware Components
LCD Message CLI Message
interface-name so- x / x / x SEF interface-name so- x / x / x - SONET severely errored
frame
interface-name so- x / x / x UNEQ interface-name so- x / x / x - SONET unequipped
Blown Fuse Indicators
The router uses fuses from the Cooper Bussman brand GMT series for the
FPCs, MCSs, PCGs, and SFMs. They are located in a fuse box on the rear
ofthemidplane. Whenthefuseforacomponentblows,thecomponent
stopsfunctioningeventhoughitisinstalledcorrectlyandthepower
supplies are still providing power to the router.
Figure 107 shows the location in the fuse box of the fuse for each component.
The labels shown in the figure do not appear on the actual fuses (the clear cover
on every fuse reads
BUSS GMT-X), but a table on the surface of the midplane
below the fuse box displays the same information.
Figure 107: Fuse Locations in the Fuse Box
J240
A
B
C
D
J241
ABCD
J244
ABCD
J242
ABCD
J243
ABCD
MCS0 12A
MCS1 12A
SFM0 10A SFM1 10A SFM2 10A
FPC4 15A
FPC2 15A
FPC1 15A
FPC0 15A
PCG0
1A
15A
SFM3 10A
SPARE 1A
SPARE 10A SPARE 12A SPARE 15A
FPC7 15A FPC6 15A FPC5 15A
1238
1A
PCG1
FPC3
When a fuse has blown but the power supplies are still delivering power to router,
the amber LED adjacent to the fuse lights. For vertically oriented fuses (in the
groups labeled
J241 through J244 in Figure 107), the LED is located below the fuse;
for horizontally oriented fuses (in the group labeled
J240), it is to the left of the fuse.
NOTE: The LEDs are each about 0.1” (2 mm) square. They might be difficult
to see when not lit.
Another indication that a fuse has blown is that the colored indicator bulb
inside it becomes visible through the clear cover on the fuse. For information
about the indicator bulb color for each fuse type, see Table 25.
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