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Introduction
This Manual is intended for use by the Service
Technician. The first portion of this manual con-
tains a basic description of disc based data play-
back and recording technologies. Self
Diagnostics are included to aid in troubleshoot-
ing. Technical Descriptions of the circuitry is fol-
lowed by a Troubleshooting Section.
The DVDR985 is the forth in a line of DVD
recorders. The DVDR1500 was the first.
Recordings can be made from broadcast trans-
missions, and from other analog or digital
sources. The DVDRW format allows the user to
record and erase a disc many times. The record-
ed discs will play on most existing and future
DVD players. The DVDR985 has a connection
for DV or Digital camcorders via an I-Link or
Firewire connection. This connection technically
is called an IEEE 1394 connection. This machine
records on 4.7Gbyte DVD+R and DVD+RW
discs. This machine uses a real-time MPEG2
Variable Bit Rate, VBR, Video encoder. The
DVDR985 plays back DVD Video, Video CD,
Audio CD, CD-R, and CD-RW discs.
Its many features include: Favorite Scene
Selection for easy editing, Index Picture Screen
for instant overview of contents, Digital Time
Base Correcter, Digital Audio output (DTS, AC-
3, MPEG, PCM), TruSurround for 3D sound,
Zoom + Perfect Still. It is Widescreen, 16:9
compatible, and has a Universal Remote
Control, 20 disc resume, Disc Lock, and One
Touch Recording.
Virgin Mode
The DVDR985, when first hooked up, needs to
get information from the user about what lan-
guage and what local broadcast system the
unit is going to operate with. Use the remote to
make those selections. The unit will not operate
until this process is completed. If you want the
recorder to start up in Virgin mode, unplug the
recorder. Plug the recorder in again while hold-
ing the STANDBY-ON button.
DVD Basics
Philips with nine other manufacturers chose a
format specification for DVDR and RW on March
16, 2001. This new format uses Real Time
recording. Its recording is compatible with DVD-
Video, and DVD ROM. The data blocks use loss-
less linking. The physical layout matches very
closely that of DVD ROM. SeeFigure 1. It also
uses Direct Overwrite when a RW disc is used.
Laser Technology
CDs use a red laser created by a diode and lens
system often called a Light Pen. Refer to Figure
2. The narrow beam of light is focused onto the
reflective layer of a disc. At the instant that focus
is achieved, the disc is spun. The laser starts on
the innermost tracks of the CD and reads out-
ward. At the beginning of the disc is the Table of
Contents. At the bottom of the Light Pen are
Monitoring Diodes. The Monitoring Diodes pro-
vide information about focus and tracking. Data
is retrieved from the disc in the form of pulses of
Figure 1 -“ DVD ROM Disc
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light reflecting from the disc. The pulses are
created by Pits in the Reflective Layer of the
disc. The Pits reflect less light than the intact
surface of the Reflective Layer, called Lands.
Disc Mechanical Layout
The DVD and CD share much of their tech-
nology. We will start with CDs and work our
way to the DVD. The CD is a plastic disc
120mm in diameter, with a thickness of
1.2mm. Refer to Figure 3. It has a silver col-
ored Reflective Layer. The maximum playing
time for a music recording on a Compact
Disc, CD, is 74 Min.
The CD is less vulnerable to damage than an
analog record. That does not mean it does
not have to be treated with care. Dirt and
heavy scratches can interfere with playability.
Figure 2 -“ CD Laser Operation
Figure 3 -“ Mechanical Layout of a CD.
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