To Check The A4 Power Supply Board Assembly - Agilent Technologies 83438A User Manual

Servicing
Troubleshooting

To check the A4 Power Supply Board Assembly

1 Check the 6.3A fuse in the rear-panel's line module FL1. Refer to "To check the
line-power fuse" on page 5-19.
2 Remove the power supply cable from J2 on the A5 Laser Driver Board
Assembly. The end of this cable can be probed to measure all of the dc voltages
supplied in the instrument. The following list shows each wire color, its color
code, and its purpose:
• Red (2) wire: +15V
• White/red (92) wire: +5V
• Violet (7) wire: –15V
• Black (0) wire: ground
• White/black (90) wire: ground
3 If no voltages are detected, check that the ac line input voltage at the cable that
connects to J1 on the A4 Power Supply Board Assembly. Measure the line
voltage across the white/gray/red wire and the gray wire. If the ac line voltage
is present, replace the A4 Power Supply Board Assembly.
5-18