500 Chapter9
Controller Section
Keyboard Problems
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 OUTPUT 718; "IP; SP 1 MHz;"
20 WAIT 2 ! Wait 2 seconds
30 OUTPUT 718;"AT 70 DB;"
40 WAIT 2 ! Wait 2 seconds
50 OUTPUT 718;"AT 30 DB;"
60 WAIT 2 ! Wait 2 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 LCD (CRT on E-series instruments) 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 A19W1.
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. On EC-series instruments, attach a logic probe to A2U35 pin 213.
On E-series instruments, 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.
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 A1A1 keyboard assembly.
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