Service manual

HT-DP2500W
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EXPLANATION OF AUTOMATIC SOUND VALUE CORRECTION CONTROL
1. Outline
The recent trend is toward rise of CD record level in the world, for example rock, dancing music, etc. In case of continuous high
level playback G-EQ (graphic equalizer) and VOL (Volume) are controlled (lowered) automatically after a lapse of specific time
(10 minutes) so as to get the easy-to-listen sound level.
2. Explanation of operation
The CD playback operation is explained below.
If hight energy exceeding X is detected, VOL is lowered to get sound easy to listen.
X
: Threshold value of control circuit operation
A : Hight energy (hatched area) exceeding
X
is detecated, and the control mode is set.
B : After a lapse of 10 minutes the control is started.
Data is fetched every 4
seconds to control.
Initial frequency
characteristics.
Hand L frequency char-
acteristics are lowered.
VOL (Volume) is lowered.
Stable control
Continued control
The output data is fetched every 4 seconds to control. When quiet music is played back, the
control is performed so as to restore the initial frequency characteristics and initial VOL values.
Control mode cancel conditions
When output exceeding
X
is not given
continuously for 10 minutes.
When quiet music is played back.
When VOL is lowered.
When the power is turned off or on.
B ~ C :
C ~ D :
A
X
B C D
0w
10 minutes
Distortion clip point
SP output
level
NOTES ON SCHEMATIC DIAGRAM
• Resistor:
To differentiate the units of resistors, such symbol as K and
M are used: the symbol K means 1000 ohm and the symbol
M means 1000 kohm and the resistor without any symbol is
ohm-type resistor. Besides, the one with “Fusible” is a fuse
type.
• Capacitor:
To indicate the unit of capacitor, a symbol P is used: this
symbol P means micro-micro-farad and the unit of the
capacitor without such a symbol is microfarad. As to electro-
lytic capacitor, the expression “capacitance/withstand volt-
age” is used.
(CH), (TH), (RH), (UJ): Temperature compensation
(ML): Mylar type
(P.P.): Polypropylene type
• Schematic diagram and Wiring Side of P.W.Board for this
model are subject to change for improvement without prior
notice.
• The indicated voltage in each section is the one measured by
Digital Multimeter between such a section and the chassis
with no signal given.
1. In the tuner section,
( ) indicates AM
< > indicates FM stereo
2. In the main section, VCR1.
3. In the power section, VCR1.
• Parts marked with “ ” ( ) are important for
maintaining the safety of the set. Be sure to replace these
parts with specified ones for maintaining the safety and
performance of the set.
SW1 ON STAND-BY ON—OFF
SW2 TIMER/SLEEP ON—OFF
SW3 DOLBY PRO LOGIC ON—OFF
SW4 EQUALIZER ON—OFF
SW5 X-BASS ON—OFF
SW6 ENTER ON—OFF
SW7 VOLUME DOWN ON—OFF
SW8 VOLUME UP ON—OFF
SW9 MEMORY/SET ON—OFF
POSITIONREF. NO DESCRIPTIONREF. NO DESCRIPTION POSITION
SW10 TUNING UP ON—OFF
SW11 TUNING DOWN ON—OFF
SW12 TUNER(BAND) ON—OFF
SW13 CD/AUX ON—OFF
SW14 VCR-2 ON—OFF
SW15 VCR-1 ON—OFF
SW23 JOG DIAL ON—OFF
SW601 VOLTAGE SELECTOR 110V