NAD C541
Service Manual

IMPORTANT NOTES
INSTRUCTION FOR HANDLING OPTICAL SYSTEM BLOCK PICK-UP

Electrostatic breakdown of the laser diode in the optical system block may occur due to a potential difference caused by electrostatic charge accumulated on clothing, human body, etc. A ground must be provided as follows to prevent any electrostatic charge during unpacking or repair work. 1. Ground for Human Body Be sure to wear a ground band (1M ohm) that is properly to remove any static electricity that may be charged on the body. 2. Ground for Work Bench Be sure to place a conductive sheet (1M ohm) or copper plate with proper grounding on the work bench or other surface on which the pick-up is to be placed. 3. Because the static electricity charge on the clothing does not discharge through the body grounding band, do not let clothing to get in contact with the pick-up unit. INCORRECT CORRECT
1.Grounding band 1M ohm

1M ohm 2.Conducttive Sheet or Copper Plate

NOTE: Laser diodes are so susceptible to damage from static electricity that even if a static discharge does not ruin the diode, it can shorten its life or cause it to work improperly.

PRECAUTIONS FOR CHECKING BEAM EMISSION

The laser beam of this unit is focused on the reflecting surface of the objective lens in the optical system block. Therefore, keep your eyes at least 12 inches (30 cm) away from the objective lens when the laser diode is ON. (Operation Check Method for Laser Diode and Focus Search Function.) When the POWER switch is turned ON after the chucking plate is removed, observe the objective lens and confirm that the following operations are performed properly. (The optical system should be at the lead-in area position when it is checked at this time.) (1) The laser should be at the innermost position after the chucking plate is removed. (2) The diffused light of the laser beam can be seen when the POWER switch is turned ON. (3) Vertical (up and down) movement of the ojective lens (2 or 3 times) will take place.
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