Keysight Technologies U3047AE04, User'S And Service Manual

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56 User’s and Service Guide U3047-90002
U3047AE04 Service Information
Troubleshooting the Test Set
If the U3047AE04 is not operating properly, use the following procedures to aid in isolating the
source of the non-RF related failures. Typical failures may be the loss of the rear panel fan or
front panel indicator lights.
No operator serviceable parts inside. Refer servicing to qualified
personnel. To prevent electrical shock do not remove covers.
The opening of covers or removal of parts is likely to expose the user to
dangerous voltages. Disconnect the instrument from all voltage sources
before being opened.
Non-RF Failures
1. Verify that the front panel Power Switch is operational.
2. The rear panel fan and front panel Active LED should operate when the Standby Switch is in
the On position.
3. AC line voltage checks (remove AC power from the instrument).
a. Ensure the proper AC line voltage is present at the instrument line cord.
b. Remove the AC power cord from the instrument. Confirm the instrument AC line module
fuse is operational. See Figure 4 on page 11 .
c. AC line fuses; remove the bottom cover of the instrument. Near the rear panel are two fuse
holders, remove the fuses and verify that they are operational. Refer to Figure 50 on page
67 .
4. DC Power; during this check you will apply AC power to the instrument with the top cover
removed. Connect the AC power cord to the Test Set.
a. Set the front panel switch to the Standby position. The fans and indicator lights should be
Off.
b. Set the standby switch to the On position. Both rear panel and internal power supply fans
should be operational and the Active LED should be On. Verify that the DC LEDs indicators
are On. Refer to
Figure 42 on page 57
.
c. If there is no DC power, suspect the power supply module or standby switch. The actual
power supply terminal connection should also be confirmed with a DVM.
d. If all of the DC Input LEDs are On and the fan is not working, replace fan.
e. If all of the DC Input LEDs are On and the switch driver board +3 or −3 Vdc LED's are Off,
remove the suspect switch wire connector from J1 to J8. If there is no +3 to
−
3 Vdc LEDs, replace the switch driver board.
The +24 Vdc indicator is not used in this instrument (Off is normal).
5. Front panel R and S indicator LED check.
a. If the indicators are not operating, continue to
“RF Switching Failures”, step 1
.