Digital Equipment DECmpp 12000/Sx 100, Руководство по обслуживанию оборудования

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6.7 Removing and Replacing the Lightpipe PCB
6.7.2 DECmpp 12000–LC/Sx Lightpipe
In the DECmpp 12000–LC DPU, the top of the enclosure must be removed to
access the lightpipe. Follow these steps to remove the top of the -LC DPU and
replace the lightpipe.
1. Turn the DPU circuit breaker OFF (down).
2. Open the DPU front door.
3. Unscrew the corner caps on the MPDA top (Figure 6–10).
4. Remove the four screws attaching the top.
5. The bottom edge of the lightpipe printed circuit board (PCB) is visible under
the top-front edge. Disconnect the ribbon signal cable connector, the 9-pin
control panel connector, and the 9-pin power connector.
6. Turn the enclosure top over, and place it on a flat surface.
7. Remove the four screws attaching the lightpipe PCB to the top inner edge
(Figure 6–11).
8. Check the alignment of the replacement PCB LEDs with the lightpipe
cutouts.
If necessary, gently bend the LED wires to align the LEDs properly with the
cutouts.
9. Use four screws to attach the replacement PCB to the top.
10. Lift the DPU top, turn it over, and put it in place.
11. Connect the lightpipe power supply cable and the control panel cable, lifting
the top front edge up, if necessary.
12. Connect the ribbon signal cable to the lightpipe PCB.
13. Use four screws to attach the DPU top.
14. Screw the corner caps onto the top.
15. Close the DPU front door.
16. Turn the DPU circuit breaker switch ON (up).
Removal and Replacement Procedures 6–21