Agilent Technologies Infiniium 90000 A, Service Manual

Page: 80 / 148

Chapter 4: Troubleshooting
Acquisition/Backplane Assembly Trouble Isolation - Scope Self Tests
80
Acquisition/Backplane Assembly Trouble Isolation - Scope Self
Tests
If the Acquisition assemblies or Backplane assembly have been removed by a prior procedure,
reinstall them.
Power up the oscilloscope and then go under Utilities > Self Test. Select the Scope Self Test
option from the Self Test pull-down menu and then press the Start Test button. If one of these
tests fails, look at the error message to see if it displays a channel specific error message (this
will be the case in most instances). If it is channel specific and it is not the Timebase Test Group
that failed then replace the acquisition board that corresponds to that channel (channels 1 and
2 - lower acquisition board, channels 3 and 4 - upper acquisition board). If it is the Timebase
Test Group that failed then replace the backplane assembly.
If the error message does not mention a channel, then refer to the discussions below for the
test that failed to see the diagnostic steps. Sometimes there is no action and the technician
simply needs to contact the software/hardware teams in order to debug the problem.
Each test also has a section called “Board Level Repair” where the troubleshooting is more
detailed than the typical assembly level repair.
Scope Self Tests
Vertical Test Group
• Front End DAC Linearity Test - This test verifies the linearity of each channel’s front end DAC.
If the test finds a problem, it will report a failure for the DAC on the associated channel.
• Board Level Repair - Re-solder or replace the DAC that is failing. If this does not fix the problem,
further hardware level debugging is necessary.
• Front End DAC MaxMin Test - This test measures the minimum and maximum output voltage
values of each channel’s front end DAC. If the test measures any values that are out of the
range of expected values, it will report a failure for the DAC on the associated channel.
• Board Level Repair - Re-solder or replace the DAC that is failing. If this does not fix the problem,
further hardware debugging is necessary.
• Otter Register - This test verifies that all of the Otter preamp registers can be correctly written
to and read from. If this test reads any registers whose values are not equal to what they were
written to, it will report a failure for the preamp on the associated channel.
• Board Level Repair - Re-solder or replace the Otter preamp that is failing. If this does not fix the
problem, further hardware level debugging is necessary.
• Overload - This test simulates an overload condition on each channel and verifies that when
such a condition exists it immediately generates an interrupt to the host processor. If such a
condition is not detected properly, the test will report a failure for the associated channel.
• There are numerous possible causes for this error. Report the error to the Infiniium software team.
Trigger Test Group
• Trigger Lvl DAC Test - This test has not been implemented yet and currently does nothing.