7.4 Reconfiguring Processor Element Array PCBs
7.4 Reconfiguring Processor Element Array PCBs
PE arrays can be downgraded so that a DECmpp system can be used with
reduced performance while PE array spares are being acquired. However,
this necessitates additional router PCBs because no PE array slot may be left
unoccupied. The process of downgrading a PE array is very similar to that of
upgrading.
Caution
Always wear antistatic straps. PE array and router PCBs can be damaged
very easily by an inadvertant static discharge.
1.
Open the DPU rear door to access the card cage.
2.
Turn off the power to the DPU as described in Chapter 1.
3.
Determine the next lower supported PE array configuration (Section 7.2).
4.
Identify the slots that will have PE array PCBs taken out and router PCBs
installed.
5.
Remove the PE array PCBs from these slots:
a.
Remove the lower PCB retainer bar.
b.
Loosen the captive screws (if present) at the top and bottom of the PCB
faceplate.
c.
Use the ejector levers to release the PCB and move it outward from its
slot.
d.
Place the PE array PCB on an antistatic mat.
6.
Carefully slide the spare router PCB into the slot. When it is almost in place,
you might encounter some resistance; push firmly to seat it in the backplane
connectors.
7.
Secure the PCB to the card cage by closing the ejector levers.
8.
Tighten the captive screws at the top and bottom of the PCB faceplate.
9.
Repeat for each PE array PCB being removed.
10. Replace the lower PCB retainer bar.
11. Open the DPU front door and inner front door (-LC only).
12. Reconfigure the backplane X-Net jumpers to support the temporary
configuration, as described in Section 7.1.3.
13. Turn on the system, as described in Chapter 1.
14. Close and lock the DPU rear door, the DPU inner front door (-LC only), and
the front door.
15. Run the PE diagnostics as a confidence check.
As soon as the PE array spares arrive, reconfigure the array to the original state
(using the new spares) and rerun PE diagnostics as a confidence check.
Backplane Jumpers and Upgrading PE Arrays 7–9
