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Lead Contents

Uninterruptible Power Supply(UPS)

Introduction Features
Principles Classifications
Engineering Data Further Information
Explanation of Terms Troubleshooting

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Primary Contents

Perform the check shown below if the UPS is operating abnormally.

ProblemCheck and remedy
The UPS does not start operation.
The LED does not appear when
the AC input is connected to
commercial power and the
"Power" switch is turned ON.
Make sure that the AC input is securely connected to commercial power.
If the status indicator does not display properly after you perform the above
operation, there is a problem with the UPS.
Refer to Interpreting beeps and displays in the user's manual.
Backup is not possible.
The computer stops when a power
failure occurs.
The battery may not be fully charged.
Charge the battery for at least the specified charging time.
When input power supply is connected to the UPS and the power is turned ON,
battery charging operation starts.
When the "Power" switch is turned OFF, the battery charging operation does
not start.
Backup is performed too
Frequent switching is performed
although a power failure does not
You hear the sound of switching.
Variations (decrease) in the input power occur frequently. Or, noise may be
included that significantly distorts the voltage waveform of the input power.
・ Try and check what happens when connecting the UPS to a different wall
outlet (commercial power) located some distance away from the device
consuming a large amount of power.
・ This problem may occur also when you connect many devices to a plug strip or
extension cord connected to the UPS if it is a long or thin cable.
The power is not turned ON even
when the "Power" switch is
If the status indicator displays "h-" or "l-," the input voltage is outside the
input voltage range and the UPS cannot start.
Check if the input voltage is within the input voltage range.
The battery replacement alert
"bn" is displayed.
・ Battery replacement alert "bn" blinks:
The battery is judged to be deteriorated in the self-diagnosis test.
Backup operation lasts only for a short period of time. Replace the battery.
Refer to Checking the battery in the user's manual.
・ Battery replacement alert "bn" turned ON:
The battery life counter has counted up to the limit.
The battery has been used up to its end-of-life. Replace the battery.
Refer to Notification that the battery needs to be replaced in the user's manual.
The UPS life alert "Un" is
The UPS has been used up to its end-of-life.
Replace the UPS with a new one as soon as possible.
The status indicator displays "0L"
and the beeper sounds every 0.5
There are too many connected devices.
Reduce the number of connected devices until "0n" is displayed on the status
The status indicator blinks "E0",
and the beeper sounds at 0.5-
second intervals.
Output stopped due to exceeded connection capacity.
Turn OFF all power to the UPS and connected devices, and reduce the number
of connected devices. Then, turn the power to the unit and connected devices
back OK and check whether "0n" is displayed on the status indicator.

For the user's manual, refer to the Uninterruptible Power Supply (UPS) User's Manual (Cat. No. U702).