If The Trace Display Is Unusual Or Unexpected; If You Can't See A Channel - HP 54645A User's And Service Manual

Testing, Adjusting, and Troubleshooting

If the trace display is unusual or unexpected

If the trace display is unusual or unexpected
Check that the Time/Div setting is correct for the expected frequency
range of the input signals.
The sampling speed of the oscilloscope depends on the Time/Div setting.
Thus, when the Time/Div setting is slower than 1 s/div, the oscilloscope may
be sampling too slowly to capture all the transitions on the waveform.
Check that all oscilloscope probes are connected to the correct signals
in the circuit under test.
Check to see that the ground lead from the cable is securely connected
to ground in the circuit under test. For high-speed measurements, each
probe's individual ground should also be connected to a ground point
closest to the signal point in the circuit under test.
See chapter 1 for more information on probing considerations.
Check that the trigger setup is correct.
A correct trigger setup is probably the most important factor in helping you
capture the desired data. See the chapter "Triggering HP 54645A/D
Oscilloscopes" for information on triggering, particularly pattern and
advanced triggers and information on logic oscilloscope triggering concepts.
Check that Autostore is turned off, then press Erase.
Press Autoscale.

If you can't see a channel

Check that the oscilloscope probe cable is securely connected to the
input connector.
Check that the oscilloscope probe lead wires are securely inserted into
the connector assembly and that the grabbers make good contact with
the probe lead wires.Check that the grabbers are securely connected to
the nodes in the circuit under test.
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