Important Notes - NAD C 541 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 poten-
tial 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
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.
1.Grounding band
1M ohm
10
CORRECT
1M ohm
2.Conducttive Sheet
or Copper Plate