Check 9, Cpu Fuse High Lead Voltage; Check 10, Fuse And Line Switch - Agilent Technologies 4339B Service Manual

Check 9, CPU Fuse High Lead Voltage

1. Turn on the 4339B.
2. Using a multimeter, check if the dc voltage at the high lead of the fuse F1 on the CPU Board
shown in Figure 4-11 is +5
3. If the voltage is in the range, replace the A2 CPU Board Assembly, otherwise replace the A1
Main Board Assembly.
Note
If the multimeter reading is correct, the F1 fuse on the A2 CPU Board
Assembly is most suspicious. Replacing only the fuse may x the problem.
Note When replacing the A2 CPU Board Assembly, refer to \Replacing the A2 CPU
Board Assembly" in Chapter 3 for handling the ROM and EEPROM on the A2
Assembly.

Check 10, Fuse and Line Switch

1. Check that the fuse on the 4339B rear panel is not blown.
2. Check that the line switch on the A5 AC Inlet Board Assembly is not defective.
3. If passed, proceed to \Check 11, DC-DC Converter Input Voltage", otherwise replace the
defective line switch or blown fuse.
6
0.2 V.
Figure 4-11. Location of High Lead of A2F1 Fuse
T roubleshooting 4-15