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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 ! Wait2 seconds
30
OUTPUT718;"AT70DB;"
40 WAIT 2 ! Wait2 seconds
50
OUTPUT718;"AT30DB;"
60 WAIT 2 ! Wait2 seconds
70 OUTPUT
718;"AT
10
DB;"
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 8,
“ADC/Interface Section.”
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. Attach a logic probe to A2U2 pin 2. Look for pulses while pressing a key and rotating the
knob (RPG). This is the interrupt request signal for the keyboard and RPG.
i’. 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.
lo-16
Controller Section