Agilent Technologies 4352B, Service Manual

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ST ART HERE
1. Check Error Messages
Turn the analyzer power on. If one of error messages listed below appears on the display ,
follow the instruction of the displayed error message . If no error message is displayed,
continue with the next Check the F an is R otating.
Error Messages Instruction
POWER FAILED ON - - - One or some of A2 power supplies , +15 V , +8.5V , +5.3 V ,
+5 V , -5 V , -15 V are displayed in - - - of the message . The
displayed power supplies are shut down due to the trouble
on the A2 post-regulator . Continue with the Check the A2
Seven LEDs in this ST ART HERE.
POWER FAILED ON PostRegHot This indicates A2 power supplies , +15 V , +8.5 V , +5.3 V ,
+5 V , -5 V , -15 V , are shut down due to too hot heat sink
on A2 post-regulator . Cool down the analyzer for about 30
minutes . Then turn the analyzer power on. If this message is
still displayed, replace A2 post-regulator .
These messages are associated with the power supplies functional group . These messages
indicate the A2 protective shutdown circuit is shutting down some of A2 power supplies to
protect them from over current, over voltage , under voltage , and too hot conditions . F or more
information about the A2 shutdown circuit, see the Figure 5-12 P ower Supply Block Diagram 2.
Note
These messages are displayed only after the power on sequence . In the power
on sequence , the analyzer checks the shutdown status of the A2 power
supplies , +15 V , +5 V , -5 V , -15 V . If a power supply is shut down, the analyzer
displays an error message and stops its operation. Once the analyzer stops the
operation, any front key operations are disabled. The only way to reset the
analyzer is turning the analyzer power o.
2. Check the F an is Rotating
Look at the fan on the rear panel. Check the fan is rotating.
If the fan is not rotating, continue with the FIND OUT WHY THE F AN IS NO T RO T A TING in
this chapter .
If the fan is rotating, continue with the next Check the A50 SHUTDO WN LED .
3. Check the A50 SHUTDO WN LED
There is a LED , SHUTDOWN LED , on the A50 DC-DC Converter . P erform the following
procedure to check it. The SHUTDOWN LED is described in the next A50 Shutdown LED .
a. Turn the analyzer power o.
b. Remove the analyzer's top cover and shield plate .
c. Turn the analyzer power on.
d. Look at the A50 SHUTDOWN LED . The LED is normally on. The SHUTDOWN LED location
on A50 DC-DC Converter is shown in Figure 5-1.
5-2 P ower Supply T roubleshooting