HP 54645A User's And Service Manual page 221

Testing, Adjusting, and Troubleshooting
To adjust the power supply
If the 5.1 V measurement is out of tolerance, adjust the 5.1 V adjustment
on the power supply; if the –5.25 V measurement is out of tolerance, adjust
the –5.25 V adjustment on the power supply (see the following figure). The
supply. If adjusting the power supply does not bring all the voltages within
tolerance, see "Troubleshooting the Oscilloscope" in this chapter.
Figure 7-5
Low Voltage Power Supply Adjustment Locations
(top side of oscilloscope)
7-32
15.75 V supplies are not adjustable and are dependent upon the 5.1 V
fan connector
+5.25 V
-5.25 V
adjust
adjust