HP 8560A

Keyboard Problems
If the analyzer does not respond to keys being pressed or the knob being rotated, the fault
could be either on the A3 Interface assembly or the A2 Controller assembly. To isolate the
A2
Controller assembly, use the following procedure. This procedure tests the analyzer response
over HP-IB and the keyboard/RPG interrupt request signal.
1. Enter and run the following BASIC program.
10 OUTPUT718; "IP; SP 1MHz;"
20 WAIT 2 ! Wait 2 seconds
30 OUTPUT 718;"AT 70 DB;"
40 WAIT 2 ! Wait 2 seconds
50
OUTPUT718;"AT 30DB;"
60 WAIT 2 ! Wait 2 seconds
70
OUTPUT718;"AT IODB;"
80 END
2. When the program runs, three or four clicks should be heard. This is the A9 Input
Attenuator changing attenuation value.
3. If the display shows the analyzer to be in RMT and the
ATTEN value displayed on the
CRT changed according to the program, the A2 Controller assembly is working properly.
Refer to Chapter 7, “ADC/Interface.”
4. If there was no response over HP-IB, the A2 Controller is probably defective. Be sure to
also check the A19 HP-IB assembly and
A19Wl.
5. If there was an improper response (for example, the displayed ATTEN value changed but
no clicks were heard), the A2 Controller is probably working properly.
6. Monitor
A2U2 pin 2 with a logic probe for pulses while pressing a key and rotating the
knob (RPG). Th
is is the interrupt request signal for the keyboard and RPG.
7. If the interrupt request signal is always low, troubleshoot the A2 Controller assembly.
8. If the interrupt request signal is always high, the fault is on either the A3 Interface or
AlAl Keyboard assembly.
9-16 Controller Section