Pioneer DEH-MG2047, Service Manual

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DEH-MG2047ZF/XU/UC
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6. ADJUSTMENT
6.1 CD ADJUSTMENT
1) Precautions on Adjustment
• The unit employs a single voltage (+5V) for the regu-
lator, thus the reference potential of the signal is
REFO (approximately 2.5V) rather than GND.
Inadvertent contact of REFO and GND during adjust-
ment can result not only in disabling normal potential
measurement but also in exposing the pickup to
strong impacts due to malfunctioning of the servo.
Therefore, you are requested to observe the following
precautions.
• Make sure that the negative probe of the measuring
instrument is not connected to REFO or GND. Special
care must be exercised so that the channel 1 negative
probe may not be connected to the oscilloscope and
the channel 2 negative probe to GND. Since the
frame of the measuring instrument is usually at the
same potential as the negative probe, the frame of
the measuring instrument must be changed to float-
ing status.
When REFO is inadvertently connected to GND, you
must immediately turn off the regulator or power
supply.
• The regulator must be turned off before mounting or
dismounting filters or wiring materials.
• You should not start adjustment or measurement
immediately after the regulator is turned on. It is rec-
ommended to run the player for approximately one
minute so that it may stabilize.
• When the test mode is turned on, various protective
functions from the software become unavailable.
Thus, you must make sure that undesirable electric or
mechanical shocks are not be given to the system.
• This model employs a photo-transistor for detecting
discs at their loading or ejection. Thus, if its outer
case is removed during repair work and internal parts
are exposed to light of strong intensity, malfunctions
including the following can result:
∗
The eject button becomes inoperable during play.
Pressing the eject button does not eject a disc and
play is continued.
∗
Loading becomes unavailable.
If a malfunction is recognized, appropriate remedial
actions must be taken. Such actions include chang-
ing the light source position, changing the unit posi-
tion and applying a cover to the photo-transistor.
• When you press the EJECT key to eject a disc, you
must not touch any other key until the ejection is
complete.
• If you press the UP or DOWN for the focus search in
the test mode, you must turn the power off immedi-
ately. (Otherwise, the lens will be forced to stick to
the top or bottom, potentially resulting in the burning
of the actuator.)
2) Description of the Test Mode
• Turning on the Test Mode
See page 56.
• Ending the Test Mode
Apply the reset (the reset will be applied two minutes
after the power is turned from off).
• Operation of TR JUMPs (except 100TR) continues
after your finger has left the key. CRG, MOVE and
100TR JUMP are forced to the tracking close mode as
soon as the key is released.
• Turning the power on or off resets the JUMP MODE
to the Single TR.