Teledyne LeCroy AP033 - Manual (Page 44)

AP033 Active Differential Probe
38 922260-00 Rev A
Preliminary Procedure
1. Using pliers, carefully remove each of the push buttons from the ProBus interface housing by
gently pulling them away from the housing.
2. Remove the two screws that secure the plastic cover on the cable end of the ProBus interface
housing. Gently pull on the probe cable to slide the circuit board assembly from the metal
housing.
3. Remove the 5/64 in. (2 mm) Allen head cap screw from the small cover on the back of the
probe tip. Remove the cover along with the small cover on the opposite side of the probe. Hold
the shielded portion of the probe head in one hand and gently slide the larger cover off by
pulling it away from the probe tip end.
4. Connect the AP033 Active Differential Probe output to the female end of the ProBus Extension
Cable. Be careful to align the ProBus pins with the corresponding connector correctly. Connect
the male end of the ProBus Extension Cable to Channel 1 of the oscilloscope.
NOTE: The Logic board is connected to the Amplifier board by four small 8-pin connectors.
There are no additional mechanical fasteners holding the two boards together. A small foam
pad mounted on the circuit board ensures that the connectors remain engaged while the
assembly is mounted within the ProBus interface housing. Be sure that the connectors
between the boards are firmly engaged before applying power to the probe. Operating the
probe without the logic board will not damage it. However, to ensure reliable operation, the
logic board should only be mated with the Amplifier board with the power removed, and the
ProBus connector disengaged.
5. Apply power to the oscilloscope and to the other test instrumentation. Allow at least 30
minute’s warm-up time for the AP033 Active Differential Probe and test equipment before
continuing the calibration procedure.
NOTE: The probe tip cover also serves to thermally stabilize the input circuitry. The differential
input stage of the probe utilizes discrete transistors that need to maintain an approximate
match of junction temperatures for correct DC balance. With the covers removed, this circuitry
is susceptible to drift caused by air currents flowing over the components. Remove or redirect
any fans that may be blowing air currents over the probe tip during adjustment.
Correct operation of the AP033 Active Differential Probe controls requires software version
8.1.0 or higher. You can find out the software version loaded on your Teledyne LeCroy scope by
pressing SHOW STATUS, then selecting the System menu option. In version 8.1.0 and higher,
the OFFSET controls on the probe are disabled. Offset is controlled by the OFFSET knob in the
oscilloscope CHANNEL section.