LeCroy WaveSurfer 400 Series Service Manual page 45

Trigger mode : Auto
Set the DMM with Ohms and Ohms sense to provide a 4 wire measurement.
Connect it to Channel 1.
Measure the input impedance, reverse the meter leads and measure the input
impedance.
Average these two numbers and record it in Table 2, and compare it to the limits.
Repeat the above test for all input channels.
Recall Input Impedance - 1 Mohm DC x10.lss or Set Input gain to 200 mV/div.
on all 4 Channels
Repeat the test for all input channels.
Record the measurements in Table 2, and compare the test results to the
limits in the test record.
Recall Input Impedance - 1 Mohm DC x1.lss or Set Input gain to 2 V/div. on all
4 Channels
Repeat the test for all input channels.
Record the measurements in Table 2, and compare the test results to the
limits in the test record.
Rev. D Sept 2007 Performance Verification 5-5