Symmetricom 5071A, Operating And Programming Manual

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Chapter 3 In Case of Difficulty
Power-up Problems
Operating and Programming Manual 35
Power-up Problems
In general, the 5071A will power-on and warm-up within approximately 15
minutes and operate to specifications after 30 minutes. Some instruments may
take slightly more or less time to do so and represent a normal variation of start-
up performance. There are, however, circumstances that are associated with a
lack of any activity or, cause fatal error states to occur (see event log) by
preventing a normal power-on/warm-up sequence. These situations are listed
along with a suggested remedial procedure.
• If you attempt to start the 5071A and observe no signs of activity:
1. Disconnect the instrument from ac and/or external-dc power (if present).
2. Check the ac fuse located in the rear-panel ac power module (also check
the dc fuse if external-dc power is present).
3. Replace the fuse as needed, then attempt restart.
4. If the fuse blows again, disconnect power immediately and contact the
nearest Symmetricom Customer Service Center for assistance.
• If you attempt to start the 5071A when its temperature is below 0˚ Centigrade,
the allotted maximum 45-minute power-up/warm-up time may not be
sufficient to heat both the Cesium Beam tube oven and VCXO oven.
1. Let the instrument warm up to room temperature.
2. Attempt to restart the instrument.
• If you connect 240-volt power to the instrument when it is set for 120 volts,
the ac-power fuse will blow.
1. Replace the ac-power fuse.
2. Wait at least 15 minutes as required by internal power-supply circuit
time constants.
3. Attempt to restart the instrument.
• If you attempt to start the 5071A in a normal operating environment with the
correct ac-voltage set and the instrument reports a fatal error or appears
otherwise unresponsive.
1. Attempt restart twice if the instrument does not power up.
2. Contact the local Symmetricom Customer Service Center for assistance.