Toshiba Strara CTX Series, Installation And Maintenance Manual, Page: 66 / 290

2-14
Strata CTX I&M September 2002
Strata CTX100 Installation
Step 7A: Check the -24 Volt Circuit Breakers
The APSU112 provides two -24v circuit breakers as shown in Figure 2-14 . If a low resistance between
–24 volts and ground exists the circuit breaker will trip. Usually the front panel DC green LED
indicator will turn off but not always. Also if AC power is recycled the DC LED indicator may turn
back on – even if the –24 volt circuit breaker is tripped.
Circuit Breaker Location and Slot Assignments (see Figure 2-14 )
◆
The circuit breaker V1, located directly below the FG screw, protects the first and second cabinet
slots.
◆
The circuit breaker V2, located next to the BASE jumper connector, protects the third and fourth
cabinet slots.
Reset Circuit Breaker
1. A defective PCB or an external short on the MDF may cause the circuit breaker to trip.
2. If you suspect that a –24 volt circuit breaker has tripped, try to reset it by:
♦
Turn the power supply DC power switch off and unplug the power supply AC power cord
from the AC outlet – the inside of the power supply has exposed voltages.
♦
Gently press in each circuit breaker and listen for or try to feel it click. If the breaker was
tripped, you will hear or feel it click back to the set position.
♦
If the circuit breaker resets, pull the PCBs and check for MDF shorts associated with the slots
assigned to the tripped circuit breaker. Remove any defective PCBs and MDF shorts.
♦
Restore power and verify the system is working normally.
3. Replace the power supply if the circuit breaker continues to trip and a defective PCB or short
cannot be found. See “Step 7D: Remove and Replace the Power Supply (if required)” on
Page 2-15 .
Step 7B: Check the AC Power Fuses
The APSU112 provides two AC power fuse as shown in Figure 2-14 . If low resistance to ground exists
the fuse may blow. The front panel AC green LED indicator will turn off.
If you suspect that a AC fuse has blown you may check it by:
1. Turn the power supply DC power switch off and unplug the power supply AC power cord from the
AC outlet – the inside of the power supply has exposed voltages.
2. Remove each fuse and check that it is less than 0.3 ohms. Replace the fuse if it is defective. The
fuse size is T6.3AH 250V.
3. If you replace the fuse and it continues to blow, pull the PCBs and check for cabinet shorts.
Remove any defective PCBs and cabinet shorts.
4. Replace the power supply if the fuse continues to blow and a defective PCB or short cannot be
found. See “Step 7D: Remove and Replace the Power Supply (if required)” on Page 2-15 .
Step 7C: Check the Power Factor Indicator and Reset Button
The front panel of APSU112 provides a Power Factor LED and Reset button. If the cabinet power
factor is exceeded by overload of PCBs, the PF LED will turn on.