To Balance And Adjust The Power Supplies (Current Clamp Method) - Sun Microsystems StorEdge A7000 Service Manual

6.12.1 To Balance and Adjust the Power Supplies
(Current Clamp Method)
If the difference in current between power supplies A and B is greater than 12 amps,
you need to balance the power supplies.
6.12.1.1 Measure the Current Draw Difference Between Supplies A
and B
1. Power on the Sun StorEdge A7000 and bring the subsystem to the ROM Monitor
prompt (ROM >>).
These procedures are described in Chapter 7.
2. Open the front cabinet door.
3. Unscrew the power supply retaining screws from the left subsystem power supply
tray. See
4. Fold down the tray, pulling on the rubber grips.
This tray contains the power supplies A and B for subsystem with the power supply
being replaced or adjusted.
5. Set your DVM to DC voltage mode.
6. Measure the DC voltage across the +5 VDC and GND backplane bus bars shown
in
FIGURE 6-17
7. Connect the Fluke i410 current clamp (or equivalent) to the DVM's V and COM
inputs.
8. Set your DVM to mV (millivolts) and power on the current clamp.
9. Zero the DVM.
The scale on the DVM is 1 amp per mV.
10. Put the current clamp on power supply A, V1+.
Place the clamp as close as possible to the red cable on V1+.
11. Record the measurement.
12. Repeat Step 10 and Step 11 for power supply B, V1+.
If the difference in current between power supplies A and B is greater than 12 amps,
balance and adjust them according to Section 6.12.1.2 "Balance and Adjust the Power
Supplies" on page 6-45.
.
FIGURE 6-15
and record this voltage.
Chapter 6 FRU Removal and Replacement 6-43