Agilent Technologies 856290216 service manual Troubleshooting to a Functional Section

Troubleshooting to a Functional Section

1.Refer to Table 7-l for the location of troubleshooting information.

2.If the HP 85629B test and adjustment module (TAM) is available, refer to “The TAM (Test and Adjustment Module)” in this chapter.

3.If error messages are displayed, refer to “Error Messages” in this chapter. You will find both error descriptions and troubleshooting information.

4.If a signal cannot be seen, and no errors messages are displayed, the fault is probably in the RF Section. Refer to Chapter 12, “RF Section.”

5.Blank displays result from problems caused by either the controller or display/power-supply sections. Because error messages 700 to 759 caused by the controller section cannot be seen on a blank display, use the following BASIC program to read these errors over HP-IB. If the program returns an error code of 0, there are no errors.

10DIM Err$ cl281

20OUTPUT 718 * “ERR’ - f* ”

30ENTER 718; ‘Err$

40PRINT Err$

50END

a.If there is no response over HP-IB, set an oscilloscope to the following settings:

Sweep time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2 ms/div Amplitude scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 V/div

b. The signals at A2J202 pin 3 and pin 14 should measure about 4 V p-p. If the levels are incorrect, refer to Chapter 10, “Controller Section,” and troubleshoot the A2 controller assembly.

c. Set the oscilloscope to the following settings:

Sweep time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 ms/div Amplitude scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2 V/div

d. The signal at A2J202 pin 15 should consist of TTL pulses. If the signal is at a constant level (high or low), troubleshoot the A2 controller assembly.

6.Display problems such as intensity or distortion are caused by either the controller or display/power-supply sections. Refer to Chapter 10, “Contoller Section,” or Chapter 13, “Display/Power Supply Section.”

7-8 General Troubleshooting