DS8000 Service Documentation Version 7.5

MAP21F1 DC-UPS should be off when UEPO switch is off

About this task

Both DC-UPSs should be off (all LEDs not lit) when the UEPO switch at the front of the rack is in the off (tripped) position. The UEPO switch has two sets of contacts, one set of contacts for each DC-UPS. Each set of contacts has a two-wire UEPO loop cable that goes to the DC-UPS J5 connector. When the UEPO switch is on (normal operation), the circuit is closed and some DC-UPS LEDs should be lit. When the UEPO switch is tripped off, the circuit is open and all DC-UPS LEDs should be off.

Procedure

Ensure that the rack operator panel UEPO switch is in the off (tripped) position. The bottom of the switch is pushed in. See Figure 1.
Figure 1. UEPO switch
Both DC-UPS should have all LED indicators off. Find the condition that applies:
- Some LED indicators are lit for both DC-UPSs, go to step 3.
- All LED indicators are off for one DC-UPS and some LED indicators are lit on the other DC-UPSS, go to step 4.
- All LED indicators are off for both DC-UPSs, the error condition is no longer occurring. Exit this MAP and return to the procedure that sent you here.
Each DC-UPS has a separate UEPO loop so the only failure that would affect both DC-UPSs would be the UEPO switch not being fully off (tripped). Do one or more of the following:
- Manually operate the UEPO switch to On and then back Off. Inspect the mechanical operation of the switch.
- Unplug the UEPO loop cable from the DC-UPS J5 connector. (See Figure 2.) Observe the DC-UPS LEDs, if they are all off, the UEPO switch needs to be replaced. If some LEDs are lit, the DC-UPS DSU needs to be replaced.
- Unplug the UEPO loop cable from the DC-UPS J5 connector. (See Figure 2.) Use a multimeter to measure the continuity between the two pins of the cable. The cable should be open (infinite resistance). If it is not, replace the UEPO switch assembly.
Figure 2. Location codes for the DC-UPS (Models 961, 96E) (rear)
At the rear of the DC-UPS with some LED indicators lit, unplug the UEPO loop cable from the DC-UPS J5 connector. See Figure 2.
Are all LED indicators now off?
- Yes, the UEPO switch assembly is failing and needs to be replaced.
- No, The DC-UPS DSU needs to be replaced.