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8. Alignments
No alignments available
9. Circuit Descriptions and List of Abbreviations
1. Introduction
2. Power Supply
3. Loader/Monoboard
4. Data Processing
5. Control and Display
6. Abbreviations
Notes:
•
Figures can deviate slightly from the actual situation, due
to different set executions.
•
For a good understanding of the following circuit
descriptions, please use the diagrams in chapter 6 and 7.
Where necessary, you will find a separate drawing for
clarification.
9.1
Introduction
9.1.1
Features
The SACD 900/DVD962SA range is a new model DVD/SACD
player and is equipped with:
•
Build in MPEG2, AC-3 and DSD decoder,
•
6 channel audio output,
•
RGB video output on SCART (Europe only),
•
YUV output,
•
Progressive scan (for DVD962SA Non-Europe models),
•
CD-RW compatible.
9.1.2
Differences
The SACD 900/DVD962SA is derived from the SACD 1000. It
has a new Audio/Video board, Front Display board,
Progressive scan board (same as used in Step2001 DVD-
player) and another Power Supply module (same as used in
Step2001 DVD-players).
9.1.3
Modules
The main modules are:
•
Power Supply Unit (PSU).
•
Mercury 1 Loader - VAL6011
•
ASD1.1 Mono Board.
•
Audio Video (A/V) Board.
•
Front Display Board.
•
Progressive Scan Board.
9.1.4
Service
This ASD1.x has the same ComPair connector as in previous
DVD generations.
Flashing of the application-SW is not possible with the ComPair
cable, except with a CD-R disc. For sets with Mask-ROM
software, replace it with a programmed Flash (available via
your Philips Service organisation).
9.2
Power Supply Unit
9.2.1
Introduction
This supply is a Switching Mode Power Supply (SMPS), which
uses the control IC UC3842 to produce pulses to drive the
Alignments
SACD 900
power 'switch' (MOSFET). The regulation of the 'duty cycle',
controls the supply output, at a fixed switching frequency
(approximately 58 kHz, determined by the RC timing
components at pin 4).
The UC3842 (item IC1) is a high performance, fixed frequency,
current mode controller for DC-to-DC converter applications.
This integrated circuit features a:
•
trimmed oscillator for precise duty cycle control,
•
temperature compensated reference,
•
high gain error amplifier,
•
current sensing comparator and
•
high current totem pole output ideally suited for driving a
power MOSFET (item Q1).
Also included are protective features consisting of input and
reference under-voltage lockouts each with hysteresis, cycle
by cycle current limiting, programmable output dead time and
a latch for single pulse metering.
9.2.2
Output Voltages
•
+12V_stdby (present during standby).
•
+5V_ stdby (present during standby).
•
+5V_digital (will switch off via Q3 during Standby).
•
+5V_AV (will switch off via Q3 during Standby).
•
3V3 (present during standby).
•
-5V (will switch off during standby).
9.2.3
Operation
Power Supply
RECTIFIER
EMI FILTER
AC
ZNRI
MAINS
SP1
SPARK GAP
IC1
CONTROL
1
Figure 9-1
Mains Input Circuit
The bridge rectifier (D1-D4) rectifies the mains voltage, after
which C5 smoothens this voltage. The DC voltage across this
capacitor is the DC input voltage (approximately 300 V), to pin
1 of transformer T1.
The mains input also consists of a (differential mode) lightning
protection ZNR1 and a (common mode) lightning protection
SP1 (spark gap).
8.
EN 103
T1
300V
1
C5
DC
Q1
D
G
6
S
3
7
R
SENSE
ZD1
C7
+12V
IC2
IC3
CL16532136 042 eps
+12V
etc
261101
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