HP 8560A, Service Manual

Page: 213 / 450

Troubleshooting to a Functional Section
1. Refer to Table 6-l for the location of troubleshooting information.
2. If the HP 85629B Test and Adjustment Module (TAM) is available, refer to “Using the
TAM” 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 11, “RF Section.”
5. Blank displays result from problems caused by either the Controller or
Supply Sections. Because error messages 700 to 755 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.
10 DIM
20 OUTPUT
30 ENTER718;
40 PRINTErr$
50
END
a. If there is no response over HP-IB, set an oscilloscope to the following settings:
Sweep Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Amplitude Scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
b. The signals at pin 3 and pin 14 should measure about 4 Vp-p. If the levels are
incorrect, refer to Chapter 9 and troubleshoot the A2 Controller Assembly.
c. Set the oscilloscope to the following settings:
Sweep Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..lms/div
Amplitude Scale
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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 9.
6-8 General Troubleshooting