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8. Maintenance
8.1 Regular Maintenance
Surge arrestors are degraded by lightening induced voltages, resulting in changes to their
discharge breakdown voltage. They require periodic checks and should be replaced if necessary.
They can be checked by removing the internal components from the arrestor cabinet. The glass
pipe part should be inspected and if it has turned black then replacement is required.
CAUTION
The surge arrestor must be periodically maintained to prevent malfunction.
8.2 Troubleshooting
In the event of failure or unexpected behaviour of the unit, the following items should be
checked.
Symptom
"5V" LED is off.
"ERROR" LED is on.
"1PPS OUT" LED does not
start to blink after power ON.
It takes a long time until
"1PPS OUT" LED starts
blinking after power ON.
During operation, the 1PPS
output is interrupted.
Data cannot be detected on
the receiving device.
The 1PPS signal or the time
data is irregular.
"1PPS OUT" LED does not
turn on.
If a failure continues, stop using the GPS receiver unit and contact the vendor.
Possible cause and / or remedy
Check that power connections to the unit are made correctly and that the power supply switch on
the front panel is ON. If so, then a failure of the internal power supply unit is a possible cause.
The GPS receiver unit is failed. The internal circuit clock has stopped oscillating.
Check the antenna location and connection.
Check that the DIP switches are set to proper positions.
In cases where the power has been turned off for 16 hours or more, internal back-up data may
be lost and it may take about 30 minutes before the unit is ready to output the 1PPS signal. This
case is not an error.
However, if 1PPS is not output after about 30 minutes, check that the antenna is installed in a
satisfactory location.
Check to make sure that the antenna is installed in a satisfactory location.
Check that the optical fibre is connected securely and that it is not damaged or severely bent
(minimum bend radius is 50mm).
Possible failure of the internal receiver.
Check that the DIP switches are set to proper positions.
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