Technical data

5-10 Chapter 5
Power Supply Troubleshooting
If the Red LED of the A15 Is ON
Verify the A15 Preregulator
Verify that the A15 preregulator is supplying the correct voltages to the A8 post regulator.
Use a voltmeter with a small probe to measure the output voltages of A15W1's plug. Refer
to Table 5-2 and Figure 5-6.
• If the voltages are not within tolerance, replace A15.
• If the voltages are within tolerance, A15 is verified. Continue to “Check for a Faulty
Assembly” on page 5-11.
Table 5-2 Output Voltages
Pin A15W1P1 Voltages
(Disconnected)
A8J2 Voltages
(Connected)
A15 Preregulator
Label
1
N/C +68 to +76.2 N/C
2
+125 to +100 +68 to +76.2 +70 V
3, 4
+22.4 to +33.6 +17.0 to +18.4 +18 V
5, 6
−22.4 to −33.6 −17.0 to −18.4 −18 V
7
N/C +7.4 to +8.0 N/C
8
+9.4 to +14 +7.4 to +8.0 +8 V
9, 10
−9.4 to −14 −6.7 to −7.4 −8 V
11
N/C +24.6 to +28.6 N/C
12
+32 to +48 +24.6 to +28.6 +25 V
NOTE The +5 VD supply must be loaded by one or more assemblies at
all times, or the other voltages will not be correct. It connects to
the motherboard connector A17J3 Pin 4.