HP 8560A, Руководство по обслуживанию

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RPG Interface
See function block J of A3 Interface Assembly Schematic Diagram (sheet 3 of 6).
latches the RPG direction from the two RPG outputs, and
Counterclockwise RPG rotation produces low-going pulses which result in a high output on
Clockwise RPG rotation results in a low output from provides the
edge to trigger one-shot which generates a 90 ms pulse. This pulse gates for
counting of RPG pulses by Gates and prevent retriggering of
until its 90 ms pulse has timed out.
1. Monitor pin 2 with
a
logic probe or oscilloscope. Pulses should be present as the
RPG is rotated.
2. Monitor pin 12 as the RPG is rotated. Pulses should be present.
3. If pulses are missing at both points, check for power and ground signals to AlAlWl and
If both power and ground are there, the RPG is probably defective.
4. If pulses are missing at only one point, check for an open or short on AlAlWl and
If these cables are working properly, RPG is probably defective.
5. Set the switch off and disconnect AlAlWl from Jumper pin
12 to pin 14 Vdc). Jumper pin 2 (RPG-02) to U511 pin 11
(HDPKD-CLK). This p rovides a 7.8
square wave to the RPG-02 input of the RPG
Interface.
6. Set the switch on.
7. Check pin 9 for narrow, low-going pulses approximately every 90 ms.
8. Check pin 13 (LRPG-RESET) for narrow, low-going pulses approximately every
90 ms.
9. Check pin 5 for narrow, low-going pulses approximately every 90 ms.
10. Check pin 5 (HRPG-IRQ) for narrow, high-going pulses approximately every 90 ms.
11. If HRPG-IRQ is correct but LRPG-RESET is incorrect, check pin 13
(LKBD/RPG-IRQ) for narrow, low-going pulses approximately every 90 ms.
12. If HRPG-IRQ and LKBD/RPG-IRQ are correct but LRPG-RESET is incorrect, suspect
a failure on the A2 Controller Assembly.
13. Check pin 3 for a 7.8 square wave. Check pin 2 for
narrow, high-going pulses approximately every 90 ms. Refer to Table 7-5 and check the
frequencies at divide-by-16 counter
14. If all the checks above are correct but the analyzer does not respond to the RPG, suspect
a problem in either the RPG or the Keyboard.
15. Set the [LINE] switch off.
16. Reconnect AlAlWl to and remove all jumpers.
7-8 Section