Agilent Technologies 4338B, Руководство по обслуживанию

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P ower Supply Section
Figure 4-8 shows the power supply section block diagram.
Figure 4-8. P ower Supply Section Block Diagram
The ac line power is connected to the A5 A C Inlet Board Assembly , which consists of the fuse ,
line switch, and varistors . The voltage selection switch on the rear panel selects the ac line
voltage from 230V or 115V . A ccording to the selection, the ac line power is connected to the
corresponding primary tap of the transformer . V aristor , VR1 protects the circuit from surge
voltage on the line power . VR2 blows fuse F1 if the 4338B is turned on with the wrong line
voltage setting selection, for example , 115V selection when using a 230V line .
The transformer secondary voltage is approximately 14 V . The ac voltage is rectied and
ltered by circuitry on the A1 Main Board Assembly , and produces approximately 14V dc . The
dc voltage is applied to the DC-DC Converter to produce regulated +12V , +5V , and 012V dc .
The dc voltages are supplied to all assemblies , either directly or indirectly via the A1 assembly .
4-10 T roubleshooting