JVC AV-21AT Schematic
STANDARD CIRCUIT DIAGRAM
AV-21AT
■ NOTE ON USING CIRCUIT DIAGRAMS
1. SAFETY
The components identified by the
critical for safety. For continued safety replace safety critical
components only with manufactures recommended parts.
2. SPECIFIED VOL T AGE AND W AVEFORM VALUES
The voltage and waveform values have been measured under the
following conditions.
(1)Input signal : Colour bar signal
(2)Setting positions of each knob/button and variable resistor
(3)Internal resistance of tester : DC 20kΩ/V
(4)Oscilloscope sweeping time : H ➞ 20µS/div
(5)Voltage values : All DC voltage values
* Since the voltage values of signal circuit vary to some extent
according to adjustments, use them as reference values.
3. INDICATION OF PARTS SYMBOL [EXAMPLE]
● In the PW board : R1209 ➞ R209
4. INDICATIONS ON THE CIRCUIT DIAGRAM
(1)Resistors
● Resistance value
No unit : [Ω]
K: [KΩ]
M : [MΩ]
● Rated allowable power
No indication : 1/4 [W]
Others : As specified
● Type
No indication : Carbon resistor
OMR : Oxide metal film resistor
MFR : Metal film resistor
MPR : Metal plate resistor
UNFR : Non-flammable resistor
FR : Fusible resistor
* Composition resistor 1/2 [W] is specified as 1/2S or Comp.
(2)Capacitors
● Capacitance value
1 or higher : [pF]
less than 1 : [µF]
● Withstand voltage
No indication : DC50 [V]
AC indicated : AC withstand voltage [V]
Others : DC withstand voltage [V]
* Electrolytic Capacitors
47/50 [Example]: Capacitance value [µF]/withstand voltage [V]
!!
! symbol and shading are
!!
: Original setting position when
shipped
: V ➞ 5mS/div
: Others ➞ Sweeping time is
specified.
● Type
No indication : Ceramic capacitor
MY : Mylar capacitor
MM : Metalized mylar capacitor
PP : Polypropylene capacitor
MPP : Metalized polypropylene capacitor
MF : Metalized film capacitor
TF : Thin film capacitor
BP : Bipolar electrolytic capacitor
TAN : Tantalum capacitor
(3)Coils
No unit : [µH]
Others : As specified
(4)Power Supply
: B1
: 12V
: 9V
: 5V
* Respective voltage values are indicated.
(5)Test point
: Test point
: Only test point display
(6)Connecting method
: Connector
: Wrapping or soldering
: Receptacle
(7)Ground symbol
# : LIVE side ground
" : ISOLATED (NEUTRAL) side ground
: EARTH ground
: DIGITAL ground
5. NOTE FOR REPAIRING SERVICE
This model’s power circuit is partly different in the GND. The difference of the GND is shown by the LIVE : (#) side GND and the
ISOLATED (NEUTRAL) : (") side GND. Therefore, care must be
taken for the following points.
(1)Do not touch the LIVE side GND or the LIVE side GND and the
ISOLATED (NEUTRAL) side GND simultaneously. If the above
caution is not respected, an electric shock may be caused.
Therefore, make sure that the power cord is surely removed from
the receptacle when, for example, the chassis is pulled out.
(2)Do not short between the LIVE side GND and ISOLA TED (NEU-
TRAL) side GND or never measure with a measuring apparatus
(oscilloscope, etc.) the LIVE side GND and ISOLATED (NEUTRAL) side GND at the same time. If the above precaution is
not respected , a fuse or any parts will be broken.
● Since the circuit diagram is a standard one, the circuit and
circuit constants may be subject to change for improvement
without any notice.
No. 56013 2-3
AV-21AT
CONTENTS
SEMICONDUCTOR SHAPES ........................................................... 2-4
BLOCK DIAGRAM ............................................................................ 2-5
CIRCUIT DIAGRAMS
MAIN PWB CIRCUIT DIAGRAM (Including CRT SOCKET PWB) ......................................... 2-7
PATTERN DIAGRAMS
MAIN PWB PATTERN ............................................................................................................. 2-11
CRT SOCKET PWB PATTERN............................................................................................... 2-13
SEMICONDUCTOR SHAPES
TRANSISTOR
BOTTOM VIEW
IC
BOTTOM VIEW
CHIP IC
E
C
B
OUT
E
IN
N
N
FRONT VIEW
E
CB
IN E OUT
B
(G)C(D)E(S)
1N
TOP VIEW
1
E
CB
E
CB
1N
TOP VIEW
CHIP TR
C
BE
TOP VIEWFRONT VIEW
1N
N
1
N
2-4 No. 56013
N
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