SAMSUNG MAX Service Manual

3 CD CHANGER MINI MINI COMPONENT
MAX-810/818
SERVICE
Manual
3CD CHANGER MINI COMPONENT CONTENTS
1. Precautions
2. Specifications
4. Alignment and Adjustments
5. Special Circuit Descriptions
6. Troubleshooting
7. Exploded Views and Parts List
8. Electrical Parts List
9. Block Diagrams
10. PCB Diagrams
11. Wiring Diagram
12. Schematic Diagrams
ELECTRONICS
© Samsung Electronics Co.,Ltd. Oct. 1997
Printed in Korea Code no. AH68-20173A
1. Precautions
Follow these safety, servicing and ESD precautions to prevent damage and protect against potential hazards such as electrical shock and X-rays.
Samsung Electronics 1-1
1-1 Safety Precautions
1. Be sure that all of the built-in protective devices are replaced.
2. When reinstalling the chassis and its assemblies, be sure to restore all protective devices, including control knobs and compartment covers.
3. Make sure that there are no cabinet openings through which people-­particularly children--might insert fingers and contact dangerous voltages. Such openings include the spacing between the picture tube and the cabinet mask, excessively wide cabinet ventilation slots, and improperly fitted back covers.
4. Design Alteration Warning: Never alter or add to the mechanical or electrical design of the unit. Example: Do not add auxiliary audio or video connec­tors. Such alterations might create a safety hazard. Also, any design changes or addi­tions will void the manufacturer's warran­ty.
5. Leakage Current Hot Check (Figure 1-1): Warning: Do not use an isolation transformer during this test. Use a leakage­current tester or a metering system that complies with American National Standards Institute (ANSI C101.1, Leakage Current for Appliances), and Underwriters Laboratories (UL Publication UL1410, 59.7).
With the unit completely reassembled, plug the AC line cord directly into a 120V AC outlet. With the unit's AC switch first in the ON position and then OFF, measure the current between a known earth ground (metal water pipe, etc.) and all exposed metal parts. Examples: Handle brackets, metal cabinets, screwheads and control shafts. The current measured should not exceed 0.5 milliamp. Reverse the power­plug prongs in the AC outlet and repeat.
6. Insulation Resistance Cold Check: (1) With the unit's AC plug disconnected from the AC source, connect an electrical jumper across the two AC prongs. (2) Set the power switch to ON. (3) Measure the resistance between the shorted AC plug and any exposed metallic parts. Example: Screwheads, antenna, control shafts or handle brackets.
If any of the exposed metallic parts has a return path to the chassis, the measured resistance should be between 1 and 5.2 megohms. If there is no return path, the measured resistance should be "infinite." If the resistance is outside these limits, a shock hazard might exist. See Figure 1-2
Device Under
Test
(Reading should not be above
0.5mA)
Leakage Currant Tester
Earth Ground
Test all
exposed metal
surfaces
Also test with plug reversed (using AC adapter plug as required)
2-Wire Cord
Antenna Terminal
Exposed Metal Part
ohm
Ohmmeter
Fig. 1-1 AC Leakage Test
Fig. 1-2 Insulation Resistance Test
Samsung Electronics1-2
1-1 Safety Precautions (Continued)
7. Components, parts and wiring that appear to have overheated or that are otherwise
damaged should be replaced with parts
that meet the original specifications. Always determine the cause of damage or overheating, and correct any potential hazards
8. Observe the original lead dress, especially near the following areas: Antenna wiring, sharp edges, and especially the AC and high voltage power supplies. Always inspect for pinched, out-of-place, or frayed wiring. Do not change the spacing between components and the printed circuit board. Check the AC power cord for damage. Make sure that no wires or components touch thermally hot parts.
9. Product Safety Notice: Some electrical and mechanical parts
have special safety-related characteristics which might not be obvious from visual inspection. These safety features and the protection they give might be lost if the replacement component differs from the original--even if the replacement is rated for higher voltage, wattage, etc.
10 Components that are critical for safety are
indicated in the circuit diagram by
shading, or . Use replacement
components that have the same ratings,
especially for flame resistance and
dielectric strength specifications. A
replacement part that does not have the
same safety characteristics as the original
might create shock, fire or other hazards.
1-2 Servicing Precautions
1. Servicing precautions are printed on the cabinet. Follow them.
2. Always unplug the unit's AC power cord from the AC power source before attempting to: (a) Remove or reinstall any component or assembly, (b) Disconnect an electrical plug or connector, (c) Connect a test component in parallel with an electrolytic capacitor.
3. Some components are raised above the printed circuit board for safety. An insulation tube or tape is sometimes used. The internal wiring may be clamped to prevent contact with thermally hot components. Reinstall all such elements to their original position.
4. After servicing, always check that the screws, components and wiring have been correctly reinstalled. Make sure that the portion around the serviced part has not been damaged.
5. Check the insulation between the blades of the AC plug and accessible conductive parts (examples: metal panels, input terminals and earphone jacks).
6. Insulation Checking Procedure: Disconnect the power cord from the AC source and turn the power switch ON. Connect an insulation resistance meter (500V) to the blades of the AC plug.
The insulation resistance between each blade of the AC plug and accessible conductive parts (see above) should be greater than 1 megohm.
7. Never defeat any of the B+ voltage interlocks. Do not apply AC power to the unit (or any of its assemblies) unless all solid-state heat sinks are correctly installed.
8. Always connect a test instrument's ground lead to the instrument chassis ground before connecting the positive lead; always remove the instrument's ground lead last.
Precautions
Warning1: First read the "Safety Precautions" section of this manual. If some unforeseen circumstance creates a conflict
between the servicing and safety precautions, always follow the safety precautions.
Samsung Electronics 1-3
1-3 Precautions for Electrostatically Sensitive Devices (ESDs)
1-4 Special Precautions and Warning Labels for Laser Products
1. Some semiconductor ("solid state") devices are easily damaged by static electricity. Such components are called Electrostatically Sensitive Devices (ESDs). Examples include integrated circuits and some field-effect transistors. The following techniques will reduce the occurrence of component damage caused by static electricity.
2. Immediately before handling any semiconductor components or assemblies, drain the electrostatic charge from your body by touching a known earth ground. Alternatively, wear a discharging wrist-strap device. (Be sure to remove it prior to applying power--this is an electric shock precaution.)
3. After removing an ESD-equipped assembly, place it on a conductive surface such as aluminum foil to prevent accumulation of electrostatic charge.
4. Do not use freon-propelled chemicals. These can generate electrical charges that damage ESDs.
5. Use only a grounded-tip soldering iron when soldering or unsoldering ESDs.
6. Use only an anti-static solder removal device. Many solder removal devices are not rated as "anti-static" (these can accumulate sufficient electrical charge to damage ESDs).
7. Do not remove a replacement ESD from its protective package until you are ready to install it. Most replacement ESDs are packaged with leads that are electrically shorted together by conductive foam, aluminum foil or other conductive materials.
8. Immediately before removing the protective material from the leads of a replacement ESD, touch the protective material to the chassis or circuit assembly into which the device will be installed.
9. Minimize body motions when handing unpackaged replacement ESDs. Motions such as brushing clothes together, or lifting a foot from a carpeted floor can generate enough static electricity to damage an ESD.
Precautions
UL : Manufactured for U.S.A. Market. CSA : Manufactured for Canadian Market. EU : Manufactured for European Market. SCAN : Manufactured for Scandinavian
Market.
This Product Complies with DHHS Rules 21CFR, Sub chapter J.At date of Manu­facture
(UL)
(SCAN)
(EU)
CERTIFIED ONLY TO CANADIAN ELECTRICAL CODE.
CERTIFIE EN VERTU DU CODE CANADIAN DE LELETRICITE SEULEMENT
(CSA)
CLASS 1 LASER PRODUCT
(EU)
Fig. 1-3 Warning Labels (Location: Enclosure Block)
Fig. 1-4 Warning Labels (Location: Disc Clamper, Inner Side of Unit Door or Nearby Unit Chassis )
CAUTION : INVISIBLE LASER RADIATION WHEN OPEN
AND INTERLOCKS DEFEATEO AVOIDEXPOSURE TO BEAM
ADVARSEL:USYNLIG LASERSTRÅLING VED ABNING
NÅR SIKKERHEDSAFBRYDERE ER UDE AF FUNKTION
UNDGA UDSAETTELSE FOR STRALING
VARO:AVATTAESSA JA SUOJALUKITUS OHITETTAESSA
OLET ALTTINA NAKYMATTÖMALLE LASERSATEILYLLE ALA KATSO SATEESEEN!
VARNING:OSYNLIG LASERSTRÅLNING NAR DENNA DEL
AR OPPNAD OCH SPARREN AR URKOPPLAD BETRAKTA EJSTRÅLEN!
Samsung Electronics1-4
1-4 Special Precautions and Warning Labels for Laser Products (Continued)
1-4-1 Warnings
1. When servicing, do not approach the LASER exit with the eye too closely. In case it is necessary to confirm LASER beam emission, be sure to observe from a distance of more than 30 cm from the surface of the objective lens on the optical pick-up block.
2. Do not attempt to handle the objective lens when the DISC is not on the tray.
1-4-2 Laser Diode Specifications
Material: GaAs+ GaAlAs Wavelength: 760-800 nm Emission Duration: Continuous
Laser Output: 0.2 mw (measured at a
1.6 mm distance from the objective lens surface on the optical pick-up block.)
1-4-3 Handling the Optical Pick-up
1. Static electricity from clothing or the body may cause electrostatic breakdown of the laser diode in the Optical Pickup. Follow this procedure:
2. Place a conductive sheet on the work bench (i.e., the black sheet used for wrapping
repair parts.) Note: The surface of the work
bench should be covered by a copper
ground plane, which is grounded.
3. The repair technician must wear a wrist strap which is grounded to the copper sheet.
4. To remove the Optical Pickup block: Place the set on the conductive sheet, and momentarily touch the conductive sheet
with both hands. (While working, do not
allow any electrostatic sources--such as clothes--to touch the unit.)
5. Ground the "Short Terminal" (located on the PCB, inside the Pickup Assembly) before replacing the Pickup. This terminal should be shorted whenever the Pickup Assembly
is lifted or moved.
6. After replacing the Pickup, reopen the Short Terminal. See diagrams below:
Precautions
THE UNIT
(1) WRIST-STRAP FOR GROUNDING
short terminal
SOH91VI(LDP)
short terminal
SOH91CI(CAR,walkman)
1M
CONDUCTIVE SHEET
short terminal
short terminal
SOH-A1
(CMS-V10,CMS-V30)
1M
SOH94T4N
(CMS-V10,CMS-V30)
2. Product Specfications
Samsung Electronics
2-1
General
Amp
Cassette
Tuner
Compact Disc
FM
MW (AM)
LW
(option)
Power source Power consumption Dimensions (mm)
Power output (Front) Total harmonic distortion Frequency range Signal to noise ratio Channel separation Input sensitivity Mic Aux
Frequency range Usable sensitivity Signal to noise ratio IF rejection ratio Total harmonic distoration Separation (Stereo)
Frequency range Usable sensitivity Signal to noise ratio IF rejection ratio Total harmonic distortion
Frequency range WOW FLUTTER Erasing effect Signal to noise ratio Total harmonic distortion
Frequency response Signal to noise ratio Channel separation Total harmonic distortion
Audio Output
125Hz ~ 8KHz(±6dB)
0.15% 60 dB 45 dB
2.5% 20Hz ~ 20KHz(±1dB)
90 dB(1kHz) 75 dB(1kHz)
0.1% (100Hz)
0.05%(1kHz)
0.2% (10kHz) 1V (1kHz 0dB)
Frequency range Usable sensitivity Signal to noise ratio
146 ~ 290KHz 60 dB 35 dB
87.5 ~ 108MHz 10 dB 62 dB 60 dB
0.2% 28 dB
522 ~ 1611KHz 54 dB 40 dB 30 dB 2%
40W / Ch(6) (THD 10%)
0.08% (1kHz) 36Hz ~ 25kHz 75 dB 50 dB
4mV (±3) 400mV (±80)
AC 230V 50HZ (option) 160W 270(W) x 317(H) x 340(D)
Specifications are subject to change without notice.
Remote Control
3. Disassembly and Reassembly
3-1 Cabinet-Top
1. Remove 11 screws holding the Cabinet-Top.
2. Lift the back of the Cabinet-Top and slide it to the rear to remove.
Figure 3-1
Samsung Electronics 3-1
Figure 3-2
Figure 3-2-1
3-2 Samsung Electronics
3-2 CD-Mecha, Door-CD
Disassembly and Reassembly
2
TRAY
1
4
5
4
1. After power is connected :
- Turn power on
- Open the tray using the open/close key
2. After power is not connected :
- Turn the Gear clockwise using the hand as shown in figure 3-2-1.
- Pull the Tray in the direction of arrow @.
3. Remove 4 screws $,% and lift the CD-Mecha.
3-3 Cabinet-Rear and Main PCB
1. Remove 7 screws % and then lift the Cabinet-Rear ^ and slide it to rear to remove (see arrow).
2. Remove the Main-PCB &.
1. Remove 3 screws *.
2. Remove the Cabinet-Rear by pushing the ÒAÓ and ÒBÓ as shown.
7
6
5
Figure 3-3
Figure 3-4
3-4 Cabinet-Front and Cabinet-Bottom
Samsung Electronics 3-3
Disassembly and Reassembly
A
8
B
Figure 3-5
3-4 Samsung Electronics
Disassembly and Reassembly
3-5 CD Mecha
13
8
2
7
6
5
4
9
3
1
10
17
16
12
11
20
15
21
14
19
CD SUB PCB
TRAY DISC ASS'Y
TRAY STOPPER
CD MAIN PCB
HOOK
BASE MAIN
18
Refer to the next page for timming point
Samsung Electronics 3-5
Disassembly and Reassembly
3-5 CD Mecha Continued
3-5-1 Tray Disassembly
3-5-2 Main Disassembly
3-5-3 CD Main PCB Disassembly
*When removing, take extreme care not to damage the hook.
1. Open the Tray Disc AssÕy by turning the Gear-Load(%) in the direction of open,then remove the Wire-Tray(Q).
2. Remove two Tray-Stopper and tray.
1. Remove the Tray-Roulette(3) from the Tray-Disc AssÕy(4) by releasing the hook.
2. Remove the PCB-Sensor AssÕy(5) from the tray by releasing the hook.
3. Remove the Worm-Motor AssÕy())from the Tray-Disc AssÕy(4).
4. Remove the Cushion-Motor(1) from the Tray.
5. Remove the Gear-Roulette(2) from the Tray-Disc AssÕy(4) by releasing the hook.
1. Remove the Table-Chuck AssÕy(6) from the Base-Main by turning it.
2. Push the Slider-Cam(!)towards right, then lift it up to remove.
3. Remove the Gear-Tray(^) from the Base-Main by releasing the fixed hook.
4. Remove the Gear-Converter(&)from the Base-Main by releasing the fixed hook.
5. Remove the Gear-Cam(%) from the Base-Main by releasing the fixed hook.
6. Remove the Belt(@) from the Pulley-Motor AssÕy(7) & the Gear-Pulley(#).
7. Remove the Gear-Pulley(#) from the Base-Main by releasing the fixed hook.
8. Remove the Gear-Load($).
9. Remove the Gear-Synchro(*).
10. Desolder two soldering points of the CD SUB PCB, then remove it from Base-Main by releasing the hook.
11. Remove the Pulley-Motor AssÕy(7) by releasing the hook.
12. Remove the PCB-SW AssÕy(8) by releasing the hook.
1. Remove the Lever-Lifter(9) from the Base-Main by releasing two hooks.
2. Remove four Rubber-CD(0) from the Lever-Lifter and then remove the Deck-CD().
3. Remove the Hook.
4. Remove the CD MAIN PCB with the soldering iron.
Figure 3-6
Figure 3-7
3-6 Samsung Electronics
Disassembly and Reassembly
* Reinstall in reverse order.
* Align the Gear-Cam with the Gear-Tray as
shown ing Figure 3-6, then mount the Tray-Disc.
* When assembling the Tray-Disc,take extreme
care not to engage with Gear-Synchro.
Gear-Cam
Gear-Cam
Gear-Cam
Gear-Cam Timming Point
Gear-Cam
Gear-Synchro
Gear-Disc
Insert
Figure 3-8
Samsung Electronics 3-7
3-6 CD Deck
1. Remove the Shaft !.
2. Lift the P/U @.
Note : Take extreme care not to touch the surface of lens.
3. Lift the Center-ring #.
4. Remove the Spring-T/Table $.
5. Remove the Turn-Table (M) %.
6. Remove 2 screws ^ and then remove the Spindle-Motor &.
7. Remove the Cover-Gear * by pushing the hook.
8. Remove the Gear (c) ( by pushing the hook.
9. Lift the Gear(b) ).
10. Remove the Gear(a) 1.
11. Remove 2 screws 2 and the then remove the Feed-Motor 3.
12. Remove the Chassis-Deck (M) 4.
Disassembly and Reassembly
3
4
5
6
12
2
1
8
9
10
11
13
14
7
4. Alignment and Adjustments
4-1 Tuner
Samsung Electronics 4-1
FM THD Adjustment
Output
Output
450kHz
60 dB
Minumum Distortion (0.3% below) (Figure 4-1)
SSG FREQ. Adjustment
point (IFT2)
98 MHz
FM DETECTOR COIL
AM(MW) I.F Adjustment
Maximum output (Figure 4-3)
SSG FREQ. Frequency Adjustment
point (IFT1)
450 kHz 522 kHz
AM I.F COIL
FM Search Level Adjustment
Adjust IVR1 so that “TUNED” of FLT is lighted (Figure 4-2)
4Gain : 20dB(CE standard)
Figure4-2 FM Auto Search Level Adjustment
Figure4-3 AM I.F Adjustment
Figure4-1 IF CENTER and THD Adjustment
SSG FREQ. Adjustment
point
(IVR1)
98 MHz
BEACON SENSITIVITY SEMI-VR(5K)
FM SSG
OUTPUT
AM SSG 450KHZ
INPUT
AM ANT IN
Speaker Terminal
60cm
IFT1
VTVM Oscilloscope
GND
30 dB
FM SSG
Output GND
Speaker Terminal
FM Antenna Terminal
Distortion Meter
Input
SET
Input
output
Oscilloscope
75
Dummy
FM IN
FM Antenna
SET
5 k
IFT1
AM RF
IFT2
FM DET
IVR1
FM AUTO STOP ADJ.
* When adjusting T.H.D., readjust I/F coil on the Tuner Pack.
4-2 Samsung Electronics
4-2-1 To Adjust Tape Speed
* Measuring tape: i) MTT-111 (or equivalent)
(Tapes recorded with 3kHz)
ii) MTT-5512 (or equivalent)
Notes
NOR SPEED
Control
1
2
MTT-111(3KHZ)
MTT-111(3KHZ)
3000 ±30kHZ
Fig. 4-4
Fig. 4-4
A&B Deck deviation : 60Hz
-
5200~6600Hz Check
Remark
Standard
Figure
Location no.
Item
Step
Tape
JVR1
No Adjustment
HI SPEED Control
Azimuth
1
MTT-111CN
8KHZ
Fig. 4-6
Output:Maximum
Remark
Standard
Figure
Location no.
Item
Step
Tape
HEAD
L,R Unbalance
1
2
MTT-112B(1KHZ)
MTT-5512
3000 ±30KHZ
Fig. 4-5
Fig. 4-5
VTVM (A-DECK)
85KHZ±1KHZ
JR30
Remark
Frequency Range
Figure
Location no.
Item
Step
Tape
JVR3R
JL3
Record Frequency
TP3
Cassette Deck
Speaker Terminal
output
LINE OUT
Frequency Counter
Figure 4-4
Figure 4-6
Recording /Play head
REVERSE PLAY
AZIMUTH control knob
Figure 4-5
In Out
Cassette Deck
Oscilloscope
SET
(GND)
VTVM
V H
4-2 Cassette Deck
Alignment and Adjustments
Samsung Electronics 5-1
5. Special Circuit Descriptions
5-1 RF Amp Block
5-1-1 RF Amplifier
5-1-2 Focus Error Amp
PD1
PD2
VC
RF-
RFO
RF SUMMINGAMP
VC
VC
VB
10K
58K
IV AMP
VA
10K
58K
IV AMP
+
-
+
-
+
-
65
66
73
74
32K
160K
4K
32K
164K
3K
+
-
+
-
+
-
63
59
FE1
VB> VA>
SW1
FEBIAS
FEBIAS
sev-stopb
VC
fe-stopb
fcmpo
sev-stop
X1 X2 X4 X8 X16
<5 Bit Counter>
The two currents from input pins PD1 (A+C) and PD2 (B+D) are converted into voltages through I/V Amp, and they are added to RF summing Amp. The photo diode (A+B+C+D) signal which is I-V changed is outputted by RFO (pin74). At this pin, the eye pattern can be checked.
The output of the focus error amp is the difference between RF I-V AMP(1) output Va and RF I-V AMP(2) output Vb,just is the Photo Diode ((A+C) - (B+D)) signal which is I-V changed. The focus error bias voltage applied to the (+) of focus error amp can be changed by D/A converter as shown in diagram, so that the offset of focus error amp can be adjust automatical. Focus error bias can be adjusted from the range of +100mV ~ -100mV by connectiong the resistor with pin 63 (FEBIAS).
Special Circuit Descriptions
5-2 Samsung Electronics
5-1-3 Tracking Error Amp
5-1-4 Focus OK Circuit
The current signals from the side spot photo diode (E and F) are input to the E and F pin and converted into voltage signals by E I-V and F I-V AMP. The output of tracking error amp is due to the difference between E I-V AMP voltage output. The E-F balance can be adjusted by modifying the gain of E I-V AMP, and the tracking gain(Pin TE1) can be adjusted automatically by micom program.
Extracting the DC part of RFI and RFO and comparing with the basic DC level, if RF Level is more than basic level, the FOK is output. The focus OK circuit generates a timing window of focus on to monitor the focus search status of focus serve.
+
-
79
68
67
F
E
EI
TGFI
BAL< 4 0 > GAIN< 3 : 0 >
from Digital
TGL
TGH
TE1
LPFT
BALL
To ISTAT,TRCNT
BALH
GAIN-UP/DOWN
75K
220K
110K
56K
27K
13K
13K
16K
7.5K
3.3K
1.5K
IV AMP
IV AMP
WIN COMP
WIN COMP
54 55
-
40K
40K
40K
90K
57K
FOK
VC+0.625V
+
-
74
75 40
+
-
Special Circuit Descriptions
Samsung Electronics 5-3
5-1-5 Mirror Circuit
5-1-6 EFM Comparator
After RFI signal is amplified by mirror amp, mirror signal is held in peak and bottom circuit. The following of 100KHZ traverse is possible in peak hold circuit and the loss of track count due to defect is counted in bottom hold circuit. Mirror output beyond 2KHz is. ÒLÓ at track on disc, ÒHÓ at interval between track on disc, ÒHÓ when the defect beyond 1.4ms is detected. The time constant for the mirror hold must be sufficiently large than of the traverse signal
The EFM comparator converts a RF signal into a binary signal As the asymmertry due to variations in disc manufacturing can not be eilminated by thr AC coupling alone, the reference voltage of EFM comparator is controlled utilizing the fact that the generation probability of 1,0 50% each in the binary EFM signals.
+
-
+
-
+
-
+
-
75
1
39
38K
96K
17K
1.5K
2.5K
17K
19K
IRF
MIRROR
MCP
Peak and Bottom Hold
+
-
+
-
+
-
77
1
39
40K
100K
100K
20K
85K
19K
RFI
EFM
ASY
Special Circuit Descriptions
5-4 Samsung Electronics
5-1-7 Defect Circuit
5-1-8 APC Circuit
The RFO signal bottom, after being inverted, is held with two time constant of long and short. The short time-constant bottom hold is done for a disc mirror defect more than 0.1msec, the long time-constant bottom hold is done with the mirror level prior to the defect. By differentiating this with a capacitor coupling and shifting the level, both signals are compared to generate the mirror defect detection signal.
As the laser diode has large negative temperature characteristic in its optical output when driven with a constant current on laser diode. Therefore, the output on processing monitor photo diode, must be a controlled current for getting regularly output power, thus the APC (Auto Power Control) circuit is composed.
75K
43K
28K
75K
VC
37.5K
75
2
5 4
41
RFO
DCB
SSTOP/DFCT
DFCT
DCC2DCC1
+
-
+
-
BOTTOM
HOLD
BOTTOM
HOLD
43.5K LD
5.15K
150K
150K
150K
300K
0.75K
69
70
PD
LDON
PN
From Micom
+
-
+
-
Special Circuit Descriptions
Samsung Electronics 5-5
5-1-9 AGC Stability Circuit
5-1-10 Post Filter
5-1-11 Center Voltage Generation Circuit
The gain is adjusted by AGC Block with the function of maintainning the definite RF peak to peak level, after the operation of RF envelop detection and comparing with reference voltage. RFO level is kept stable in 1Vp-p, and input to EFM Slice.
The adjustment of audio output gain and the integration of possible de-emphasis output are executed by the low pass filter. If the control by MUTE signal from micom exist, and when input signal absent, two channel of right and left is builted in.
The Center Voltage is generated by using resistor dividing voltage.
75 78
76
IRF CAGC
ARF
EQUALIZEVCA
25K
CH2O
GC2O
GC1O
CH1O
25K
CH2I
GC2I
GC1I
GC1I
MUTEI (From Micom)
+
-
+
-
+
-
+
-
+
-
12
10
15
13
19
30K
VC
30K
+
-
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