Lens Operation Check; Check Items; How To Treat After Inspection - Nikon AF-S VR Zoom-Nikkor ED 70-200mm f/2.8G IF Repair Manual

LENS OPERATION CHECK

Check the lens operation by using a personal computer after assembling.
○ Check by using a personal computer
● Check items
１．Operation of MR encoder
・Drive the lenses for scanning and check the difference in pulses at start and at end.
・In case the MR encoder's MR head is not properly attached on the magnetic tape, the difference in pulses is
larger.
２．Lens servo stop accuracy
・Check the overrun/underrun pulses (misalignment of the stop position against the aimed position) for the
specified lens actuation.
・When mechanical irregular operation does not occur in the focus ring drive unit, underrun occurs if the cam
ring rotary weight of the MR encoder is heavy and overrun occurs if it is light.
３．Lens servo time
・Check the servo time (time from servo start to stop) with an oscilloscope when the specified lens is actuated.
・When mechanical irregular operation does not occur in the focus ring drive unit, the servo time is long if the
cam ring rotary weight of the MR encoder is heavy and is short if it is light.
４．Check of switches and lenses
・Check the ON/OFF operation of switches and the operation of the distance encoder and zoom encoder.
● How to treat after inspection
１．When the MR encoder operation is out of standard:
Adjust the MR duty again. (Refer to P. L48.)
If the pulse is out of the standard, adjust the output pulse/waveform from the MR encoder again. (Refer
to P. L20.)
If the pulse meets the standard, replace the cam ring unit.
２．When the lens servo stop accuracy is out of the standard:
Check the output pulse/waveform from the MR encoder. If it is normal, replace the cam ring unit.
３．When the lens servo time is out of the standard:
Adjust the driving frequency and motor control again.
If the lens servo time is still out of the standard after the readjustment, replace the cam ring unit.
４．When switches do not operate properly:
Check the wiring pattern of such troubled switch or replace it.
- L50 ･ AF-S VR 70-200/2.8G -
INC
JAA78151-R.3584.A