Agilent Technologies U1840A Medalist sj5000, Hardware Manual

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11-6 Agilent U1840A Medalist sj5000 Hardware Manual
11
Troubleshooting
Troubleshooting the System Power
If a power failure occurs
• Check all MCDs and RCBO for any trip.
• If there is no trip, check the incoming facilities.
• Is there power at the mains supply?
• Is the mains isolator in the on position?
• Is Q1 (the main RCBO) in the on position?
• Is the
RUN
indicator light illuminated?
• Is the
START
key switch in the ON position?
• Check that Q2 (24 V PSU) is on.
• Check Q3 and Q4 (24 V DC) are on.
• Check the supply voltage at the main terminals.
Troubleshooting the 24 V Supply
If there is no 24 V supply
• Check the 24 V supply PS1 by either measuring the output of
the power supply or by looking at the indicator light (the
latter solution is not as good a test as the former).
• Check that MCB Q2 is on.
• Check the input ac voltage for the PS1.