Keysight E3631A, Service Manual

Page: 118 / 131

5 Service
114 Keysight E3631A Service Guide
Table 5-2 Bias Supplies Voltages (MY53xx6xxx)
Some circuits produce their own local bias supplies from the main bias supplies.
Be sure to check that these local bias supplies are active. In particular, the ADC
(analog-to-digital converter), ac input, and front panel sections have local bias
supplies. Always check that the power supplies are free of ac oscillations using an
oscilloscope. Failure of bias supplies will cause many self-test failures.
Bias Supply Minimum Maximum Check At
+5V Floating 4.75 V 5.25 V
U40 pin 6 (on the top
Board)
-5.1V Floating -4.75 V -5.25 V
Anode of VR1 (on the top
Board)
+15V Floating (±25V
supplies)
14.25 V 15.75 V
Cathode of CR4 (on the
top Board)
-15V Floating (±25V
supplies)
-14.25 V -15.75 V
Anode of CR7 (on the top
Board)
+15V Floating (+6V
supplies)
14.25 V 15.75 V
U1 pin 2 (on the bottom
Board)
-15V Floating (+6V
supplies)
-14.25 V -15.75
U2 pin 3 (on the bottom
Board)
+5V Ground Ref. 4.75 V 5.25 V
U3 pin 3 (on the bottom
Board)