Technical data

Troubleshooting 4
4000 X-Series Oscilloscopes Service Guide 91
To check the line filter board AC output
When the 13 V bulk power is not being properly supplied,
this procedure tests the AC input to the power supply to
determine whether there is a problem with the line filter
board.
1 Follow the instructions in “To prepare for internal
assembly troubleshooting” on page 83.
2 Connect the power cord, and turn on the oscilloscope.
3 Verify that AC power is present at J1 on the power supply
using a DVM and probes as shown in the following picture
(remember this is an AC voltage measurement!).
Figure 17 Verify line filter board AC output
• If you have AC power equal to what is being applied to
J101 (power cord socket) on the line filter assembly,
the AC mains portion of the line filter assembly is
probably okay.
Verify AC potential between these two points