Service and Quality
Service Publications Dept.
One Philips Drive
P.O. Box 14810
Knoxville, TN 37914
Pg. SCHEMATIC DIAGRAMS AND PC BOARDS
1. OVERALL WIRING DIAGRAM
2. FRONT BOARD SCHEMATIC DIAGRAM
3. CDC KEY SCHEMATIC DIAGRAM
4. HEADPHONE SCHEMATIC DIAGRAM
5. CONTROL SCHEMATIC DIAGRAM
6. EC05 TUNER SCHEMATIC DIAGRAM
7. CASSETTE ANALOG SCHEMATIC DIAGRAM
8. CASSETTE SERVO SCHEMATIC DIAGRAM
9. CD SCHEMATIC DIAGRAM 1
10. CD SCHEMATIC DIAGRAM 2
11. POWER SUPPLY SCHEMATIC DIAGRAM
12. L/R AMPLIFIER SCHEMATIC DIAGRAM
13. AF8 SCHEMATIC DIAGRAM 1
14. AF8 SCHEMATIC DIAGRAM 2
15. FRONT CBA (COMPONENT SIDE)
16. FRONT CBA (COPPER SIDE)
17. CDC KEY CBA (COMPONENT SIDE)
18. CDC KEY CBA (COPPER SIDE)
Manual 1970
Model no.: FWC80C37
First Publish: 08-02-00
Rev. Date: 04-05-2005
Print Date: 05.04.2005
19. HEADPHONE CBA (COMPONENT SIDE)
20. HEADPHONE CBA (COPPER SIDE)
21. CONTROL CBA (COMPONENT SIDE)
22. CONTROL CBA (COPPER SIDE)
23. CD CBA (COMPONENT SIDE)
24. CD CBA (COPPER SIDE)
25. L/R AMP AND SUPPLY CBA (COMPONENT SIDE)
26. L/R AMP AND SUPPLY CBA (COPPER SIDE)
27. AF8 CBA (COMPONENT SIDE)
28. AF8 CBA (COPPER SIDE)
29. OVERALL BLOCK DIAGRAM
30. EC05 TUNER BLOCK DIAGRAM
31. CASSETTE BLOCK DIAGRAM
32. CD BLOCK DIAGRAM
33. CASSETTE WIRING DIAGRAM 1
34. CASSETTE WIRING DIAGRAM 2
REFER TO SAFETY GUIDELINES
SAFETY NOTICE: ANY PERSON ATTEMPTING TO SERVICE THIS CHASSIS MUST FAMILIARIZE
HIMSELF WITH THE CHASSIS AND BE AWARE OF THE NECESSARY SAFETY PRECAUTIONS
TO BE USED WHEN SERVICING ELECTRONIC EQUIPMENT CONTAINING HIGH VOLTAGES.
CAUTION: USE A SEPARATE ISOLATION TRANSFORMER FOR THIS UNIT WHEN SERVICING
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Page 2
Philips Consumer Electronics
Technical Service Data
Service and Quality
Service Publications Dept.
One Philips Drive
P.O. Box 14810
Knoxville, TN 37914
Manual 1970
Model no.: FWC80C37
First Publish: 08-02-00
Rev. Date: 04-05-2005
Print Date: 05.04.2005
Mechanical Assembly
REFER TO SAFETY GUIDELINES
SAFETY NOTICE: ANY PERSON ATTEMPTING TO SERVICE THIS CHASSIS MUST FAMILIARIZE
HIMSELF WITH THE CHASSIS AND BE AWARE OF THE NECESSARY SAFETY PRECAUTIONS
TO BE USED WHEN SERVICING ELECTRONIC EQUIPMENT CONTAINING HIGH VOLTAGES.
CAUTION: USE A SEPARATE ISOLATION TRANSFORMER FOR THIS UNIT WHEN SERVICING
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DISASSEMBLY INSTRUCTIONS
Dismantling the Cassette Cover
Remove Cassette CoverCassette Cover
Dismantling the CDC Module and Front Panel
Note: Position (pos.) numbers below refer to the Cabinet Exploded View
1) Loosen 18 screws to remove the Cabinet Rear (pos. 259):
- 5 screws each on the left and right side of the Cassette Cover
- 8 screws on the back of the Cabinet Rear.
2) Slide out the CDC Tray as shown, using a flat head screwdriver.
CDC Tray Removal 1CDC Tray Removal 2
3) Remove the Cover Tray CDC (pos. 106) as shown.
Cover Tray CDC Removal
4) Loosen 2 screws A and 2 screws B to remove the CDC Module (pos. 1104) as shown.
5) Remove 1 screw (pos. 305) at the bottom to separate the Front Panel Assembly from
the Plate Bottom (pos. 231).
CDC Front ViewCDC Module Removal
Dismantling the Front Board
Remove Control Board
1) Remove 1 screw C as indicated to loosen the Headphone Board (pos. 1101-E).
2) Remove 5 screws D as indicated to loosen the Plate Front (pos. 254).
Front Board View
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3) Remove 4 screws E as indicated to loosen the Front Board (pos. 1100-A).
4) Remove 5 screws F as indicated to loosen the Control Board (pos. 1100-B).
Dismantling the ETF Tape Module
1) Remove 6 screws G as indicated to loosen the ETF Tape Module (pos. 1103).
ETF Tape Module Removal
Dismantling the Rear Portion
AF Board Top View
Rear View
1) Remove 5 screws J as indicated to loosen the AF Board (pos. 1101).
2) Remove 4 screws K and unlatch M1 as indicated to loosen the Tuner Board (pos. 1102).
3) Remove 5 screws L and unlatch M2 as indicated to take out the Plate Rear (pos. 229).
4) Remove 4 screws P and unlatch M3 as indicated to free the Power Module (pos. 1105)
from the Bottom Plate assembly.
Repair Hints
1) The Knob Volume Rotary (pos. 149) can be removed by inserting a strong string into the
slot and pulling it out in the direction indicated. See picture 1.
Picture 1
2) The Jog Rotary (pos. 138) can be removed by inserting a strong string into the slot and
pulling it out in the direction indicated. See picture 2.
Picture 2
3) During reassembly of the Power Module, place the Bracket Mains Socket (pos. 232) behind
the Mains Socket and catch it onto the Rucksack (pos. 1105-201) of the Power Module. See
pictures 3 and 4.
Picture 3
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Picture 4
4) During repair, it is possible to disconnect the Tuner Board and CDC Module completely unless the
fault is suspected to be in that area. This will not affect the performance of the rest of the set.
Note: The flex cables are very fragile; care should be taken not to damage them during repair. After
repair, be very sure that the flex cables are inserted properly into the flex sockets before encasing,
otherwise faults may occur.
5) Due to the short flex cable wires in the ETF Module, the pc board should be disconnected and
reconnected on the reverse side of the tape mechanism to keep it electrically connected during
repair. See picture 5.
Picture 5
6) Use an insulation sheet to prevent the AF Board and ETF Board from being damaged or short-
circuited to any metal parts.
Service pos. A
Service pos. B
Service pos. C
CD Drive Mechanism
Mechanism Photo
CD Servicing Hints
Replacement of CD Drive
Warning
Charged capacitors on the servo board may damage the CD drive electronics when
connecting a new CDM mechanism. That is why, in addition to safety measures such
as switching off the power supply and utilizing ESD protection, additional actions
must be taken by the repair technician.
The following steps must be done when replacing the CD drive mechanism:
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1. Disconnect the CD drive flexfoil from the old CD drive.
2. Short circuit the flexfoil with a paperclip to protect the laser against ESD.
Flexfoil short-circuit
3. Remove the old CD drive.
4. Remove the short circuit from the flexfoil.
Note
The laser diode of this CD drive is protected against ESD by a solder joint which short circuits the laser
diode to ground. For proper functionality of the CD drive, this solder joint must be removed after
connection of the drive to the system.
Solder Joint Photo
Service Position
CD Mechanism Wiring
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Cabinet Exploded View
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Page 8
Philips Consumer Electronics
Technical Service Data
Service and Quality
Service Publications Dept.
One Philips Drive
P.O. Box 14810
Knoxville, TN 37914
Manual 1970
Model no.: FWC80C37
First Publish: 08-02-00
Rev. Date: 04-05-2005
Print Date: 05.04.2005
Mechanical Diagrams
REFER TO SAFETY GUIDELINES
SAFETY NOTICE: ANY PERSON ATTEMPTING TO SERVICE THIS CHASSIS MUST FAMILIARIZE
HIMSELF WITH THE CHASSIS AND BE AWARE OF THE NECESSARY SAFETY PRECAUTIONS
TO BE USED WHEN SERVICING ELECTRONIC EQUIPMENT CONTAINING HIGH VOLTAGES.
CAUTION: USE A SEPARATE ISOLATION TRANSFORMER FOR THIS UNIT WHEN SERVICING
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MAIN CABINET EXPLODED VIEWPage: 1 of 7
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TAPE MECHANISM A EXPLODED VIEWPage: 2 of 7
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TAPE MECHANISM B EXPLODED VIEW 1Page: 3 of 7
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TAPE MECHANISM B EXPLODED VIEW 2Page: 4 of 7
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TAPE MECHANISM MOTOR EXPLODED VIEWPage: 5 of 7
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CD MECHANISM EXPLODED VIEW 1Page: 6 of 7
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CD DRAWER MECHANISM TOP AND BOTTOM EXPLODED VIEWPage: 7 of 7
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Page 16
Philips Consumer Electronics
Technical Service Data
Service and Quality
Service Publications Dept.
One Philips Drive
P.O. Box 14810
Knoxville, TN 37914
Manual 1970
Model no.: FWC80C37
First Publish: 08-02-00
Rev. Date: 04-05-2005
Print Date: 05.04.2005
General Information
REFER TO SAFETY GUIDELINES
SAFETY NOTICE: ANY PERSON ATTEMPTING TO SERVICE THIS CHASSIS MUST FAMILIARIZE
HIMSELF WITH THE CHASSIS AND BE AWARE OF THE NECESSARY SAFETY PRECAUTIONS
TO BE USED WHEN SERVICING ELECTRONIC EQUIPMENT CONTAINING HIGH VOLTAGES.
CAUTION: USE A SEPARATE ISOLATION TRANSFORMER FOR THIS UNIT WHEN SERVICING
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GENERAL INFORMATION
FWC80C37 Photograph
VERSION VARIATIONS
Type /Versions: FWC80
Features and
Board used:
/22 /34 /37
Aux. Input x x x
Line Out x x x
Surround Out
Subwoofer Out x x x
Digital Out x x x
Matrix Surround
CD Text
Dolby B x
RDS x x
News x x
Dolby Prologic (DPL)
Incredible Surround
Karaoke Features
Voltage Selector
Lower Power Standby (Clock Display Off) x x
Tuner Board - EC05 System x x
Tuner Board - Tuner 95 x
ETF7 ND/DD/FR - Chapter 9 x x
ETF7 DB/DD/FR - Chapter 9A x
SPECIFICATIONS
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GENERAL:
Mains voltage : 110-127V/220-240V Switchable for /21/21M
120V for /37
220V for /33
220-230V for /22/34
230-240V for /30
Mains frequency : 50/60Hz
Power consumption
Low power standby : < 2W
Standby : < 15W
At 1/8 rated power out : 85W
Power consumption (/37)
Standby : < 15W
At 1/8 rated power out : 75W
Clock accuracy : < 4 seconds per day
Dimensions of center unit : 265 x 310 x 390mm
TUNER:
FM
Tuning range : 87.5-108MHz
65.81-74MHz for /34
Grid : 50kHz (and 30kHz for /34)
100kHz for /37
IF frequency : 10.7MHz ± 25kHz
Aerial input : 75 ohm coaxial
300ohm click fit for /37
Sensitivity at 26dB S/N : < 7µV
Selectivity at 600kHz bandwidth : > 25dB
Image rejection : > 25dB [> 75dB]
Distortion at RF=1mV, dev. 75kHz : < 3%
-3dB Limiting point : < 8uV
Crosstalk at RF=1mV, dev. 40kHz : > 18dB
MW (AM)
Tuning range : 531-1602kHz
530-1700kHz for /21/21M/37
Grid : 9kHz
10kHz for /21/21M/37
IF frequency : 450kHz ± 1kHz
Aerial input : Frame aerial
Sensitivity at 26dB S/N : < 4.0mV/M
Selectivity at 18kHz bandwidth : > 18dB
IF rejection : > 45dB
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Output sensitivity
Line out (Left/Right) : 500mV ± 2dB at 22 kohm
Subwoofer out at max. vol. (100Hz) : 1.3V ± 2dB at 22 kohm
CASSETTE RECORDER:
Number of tracks : 2 x 2 stereo
Tape speed : 4.76 cm/sec ± 2%
Wow and flutter : < 0.4% (DIN)
Fast-wind/Rewind time C60 : 130 sec.
Bias system : 75kHz ± 10kHz
Rec./PB freq. response within 8dB : 80Hz - 12.5kHz
Signal to noise ratio (unweighted) : > 44dB
1
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COMPACT DISC:
Measurement done at output conn. of the CDC module.
Set level at 6 ohms speaker loads.
Frequency response : < ± 3dB for 63Hz - 14kHz
Signal/Noise ration (unweighted) : 60dBA
Signal/Noise ratio (A-weighted) : 67dBA
THD (30Hz-16kHz) : 1.5%
Channel difference (250Hz-10kHz) : < ± 2dB
Channel separation (20Hz-20kHz) : 30dB
Channel separation (1kHz) : 40dB
[....] Values indicated are for "Tuner 95 Board" only
Anti-static table mat - large 1200x650x1.25mm 4822 466 10953
Anti-static table mat - small 600x650x1.25mm 4822 466 10958
Anti-static wristband 4822 395 10223
Connector box (1Mý) 4822 320 11307
Extension cable
(to connect wristband to conn. box) 4822 320 11305
Connecting cable
(to connect table mat to conn. box) 4822 320 11306
Earth cable (to connect product to mat or box) 4822 320 11308
Complete kit ESD3
(combining all above products) 4822 320 10671
Wristband tester 4822 344 13999
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WARNING
with the same potential as the mass of the set via a wrist wrap with resistance. Keep components and
All ICs and many other semiconductors are susceptible to electrostatic discharges (ESD). Careless
handling during repair can reduce life drastically. When repairing, make sure that you are connected
tools also at this potential.
Safety regulations require that the set be restored to its original condition and that parts which are
identical with those specified be used.
Warning !
Invisible laser radiation when open. Avoid direct exposure to beam.
"After servicing and before returning set to customer perform a leakage current measurement test
from all exposed metal parts to earth ground to assure no shock hazard exist. The leakage current
must not exceed 0.5mA."
Handling Chip Components
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Handling Chip Components
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Philips Consumer Electronics
Technical Service Data
Service and Quality
Service Publications Dept.
One Philips Drive
P.O. Box 14810
Knoxville, TN 37914
Manual 1970
Model no.: FWC80C37
First Publish: 08-02-00
Rev. Date: 04-05-2005
Print Date: 05.04.2005
Electrical Adjustments
REFER TO SAFETY GUIDELINES
SAFETY NOTICE: ANY PERSON ATTEMPTING TO SERVICE THIS CHASSIS MUST FAMILIARIZE
HIMSELF WITH THE CHASSIS AND BE AWARE OF THE NECESSARY SAFETY PRECAUTIONS
TO BE USED WHEN SERVICING ELECTRONIC EQUIPMENT CONTAINING HIGH VOLTAGES.
CAUTION: USE A SEPARATE ISOLATION TRANSFORMER FOR THIS UNIT WHEN SERVICING
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Page 24
Adjustments
Safety Instructions:
WARNING
All ICs and many other semiconductors are susceptible to electrostatic discharges
(ESD). Careless handling during repair can reduce life drastically. When repairing,
make sure that you are connected with the same potential as the mass of the set via
a wrist wrap with resistance. Keep components and tools also at this potential.
Safety regulations require that the set be restored to its original condition and that
parts which are identical with those specified be used.
Invisible laser radiation when open. Avoid direct exposure to beam.
After servicing and before returning the unit to the customer, perform a leakage
current measurement test from all exposed metal parts to earth ground to assure no
shock hazards exist. The leakage current must not exceed 0.5mA.
Schematic Notes:
1. All resistor values are in ohms, and the value multiplier is often
used to indicate decimal point location (e.g., 2K2 indicates 2.2K).
2. Resistor values with no multiplier may be indicated with either an
“E“ or ”R“ (e.g., 220E or 220R indicates 220 ohms).
3. All capacitor values are expressed in Microfarads (e.g., u = x10-6),
nanofarads (e.g., n = x10-9), or picofarads (e.g., x10
-12
).
4. Capacitor values may also use the value multiplier as the decimal
point indication (e.g., 2p2 indicates 2.2pF.).
5. Voltages listed on schematics often use a comma to indicate the
decimal point location as it is perceived as being ”more visible.“
Refer to individual schematic diagrams for all other component indications.
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Anti-static table mat - large 1200x650x1.25mm 4822 466 10953
Anti-static table mat - small 600x650x1.25mm 4822 466 10958
Anti-static wristband 4822 395 10223
Connector box (1Mohm) 4822 320 11307
Extension cable
(to connect wristband to conn. box) 4822 320 11305
Connecting cable
(to connect table mat to conn. box) 4822 320 11306
Earth cable (to connect product to mat or box) 4822 320 11308
Complete kit ESD3
(combining all above products) 4822 320 10671
Wristband tester 4822 344 13999
PC Board Location
Display Location of PC Boards
MEASUREMENT SETUPS
Display FM Tuner Measurement SetupDisplay AM Tuner Measurement SetupDisplay CD Measurement SetupDisplay Tape Deck Recorder Measurement Setup
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Service Test Program
Display Service Test Program
ADJUSTMENT TABLES
Display Tuner Adjustments - ECO5
Display Tuner CBA Top View
Display Tuner CBA Bottom View
Display Tape Mechanism Adjustment Table
Display Tape CBA Top View
Display Tape CBA Bottom View
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Display Location of PC Boards
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Display FM Tuner Measurement Setup
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Display AM Tuner Measurement Setup
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Display CD Measurement Setup
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Display Tape Deck Recorder Measurement Setup
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Display Service Test Program
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Display Tuner Adjustments - ECO5
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Display Tape Mechanism Adjustment Table
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Philips Consumer Electronics
Technical Service Data
Service and Quality
Service Publications Dept.
One Philips Drive
P.O. Box 14810
Knoxville, TN 37914
Manual 1970
Model no.: FWC80C37
First Publish: 08-02-00
Rev. Date: 04-05-2005
Print Date: 05.04.2005
Training Information
REFER TO SAFETY GUIDELINES
SAFETY NOTICE: ANY PERSON ATTEMPTING TO SERVICE THIS CHASSIS MUST FAMILIARIZE
HIMSELF WITH THE CHASSIS AND BE AWARE OF THE NECESSARY SAFETY PRECAUTIONS
TO BE USED WHEN SERVICING ELECTRONIC EQUIPMENT CONTAINING HIGH VOLTAGES.
CAUTION: USE A SEPARATE ISOLATION TRANSFORMER FOR THIS UNIT WHEN SERVICING
Note: Position (pos.) numbers below refer to the circuit diagram.
The primary circuitry depends on the version:
• Versions with fixed primary voltage: 100VAC for /26
120VAC for /37
220-240VAC for /22/25/30/33/34
Versions /22/25/26/37 use radial type fuse 1201, versions /30/33/34 use glass tube fuse 1202.
For correct replacement see service printing on CBA, version table in circuit diagram, or parts list.
• Versions with switchable primary voltage: 110-127 / 220-240VAC for /21
In version /21 voltage selector 1210 is built-in and each primary winding is protected
separately (fuses 1201 and 1200).
For correct replacement see service printing on CBA, version table in circuit diagram, or parts list.
• European versions – ”low power standby feature“
For detailed description see below.
Circuit details:
• Low power standby feature
An additional small standby transformer, connected in series to the mains
transformer, reduces power consumption in standby mode. When power is switched
on, the control line ECOgoes low, relay 1208 is activated, and standby transformer
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Page 37
5211 is shorted and turned off.
When the set is switched off (standby) the control line ECO goes high, relay 1208 is
not activated, and standby transformer 5211 is now connected in series to the
primary winding of the mains transformer 1008. As the impedance of the standby
transformer is much higher than the impedance of the mains transformer, the mains
voltage is divided by approx. 85% (standby transformer) to 15% (mains
transformer). Thus the mains transformer delivers very low secondary voltage, and
power consumption is less than 100mW.
Via standby transformer and rectifiers 6209-6212 the supply voltage +C is
substituted. The 5,6V regulator is still working and so the microprocessor is kept
running.
• DC voltages +A, +B1/+B2, +C
These voltages supply the Super Class G amplifier, which is described later.
The whole power supply is optimized for the special characteristics of this type of
amplifier. For that reason several ”tricky“ details have been applied to ensure
optimal efficiency and symmetrical load to the mains transformer.
Generation of +A
Common full wave rectifying with bridge rectifier 6201, using 100% secondary
winding of mains transformer (pins 11-15).
Generation of +B1/+B2
The power supply is designed for both 2-channel and 4-channel
applications.
While for 2-channel applications only one supply voltage (+B1) is sufficient,
4-channel applications require an additional supply part (+B2) which
supplies the Center/Surround amplifiers and the +12V regulator (the current
required by four amplifiers would overload a single rectifier).
The supply for 2-channel versions consists of one full wave rectifier:
– 2 diodes of bridge rectifier 6201, with 6204/6205 for generation of +B1
– +B2 is connected in parallel with a bridge wire.
The supply for 4-channel versions consists of two separate full wave
rectifiers:
– 2 diodes of bridge rectifier 6201, with 6204/6205 (for +B1) and
– 2 diodes of bridge rectifier 6201, with 6202/6203 (for +B2)
using approx. 70% secondary winding of mains transformer (pins 11-14 and
pins 12-15).
Display +B2 Supply Voltage Generation
Generation of +C
Full wave rectifying with two diodes of bridge rectifier 6201, using 50%
secondary winding of mains transformer (pins 13-15/13-11).
Display +C Supply Voltage Gereration
Display Simplified +C Generation
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• Supply voltages for FTD (Fluorescent Tube Display)
The FTD requires two supply voltages, delivered by separate windings of
the mains transformer:
– 4,5VAC for FTD heating (transformer pins 16/17)
– -30V stabilized by the -30V regulator located on the amplifier part. The
supply part delivers -35V unstabilized (transformer pins 9/10), typical value:
-35V to -45V.
• Stabilized +5V6
Stabilizer 7201 generates the supply voltage +5V6 for the microprocessor.
In a fault condition the output voltage can rise up to approximately 17V,
which would definitely damage the device. Therefore an overvoltage
protection for the +5V6 supply is implemented. Whenever the output of the
stabilizer rises above 7,5V, the base of 7202 reaches 0,7V (7,5V - voltage
drop on 6207), the transistor switches through, and short circuits the input
voltage. This causes the safety resistor 3204 to open and interrupt the
circuit immediately.
• Temperature monitoring
The mains transformer is equipped with an NTC, embedded in the
secondary winding (pins 8/9). Via the NTC line the temperature of the mains
transformer is continuously monitored by the microprocessor. Further
actions depend on the software of the set. Usually the set will be switched to
standby mode when the transformer is overheated.
• Power down (PWDN) monitoring
In order to enable proper switch off conditions the mains supply is
monitored by the microprocessor via the PWDN line. If the mains supply is
interrupted the PWDN line becomes low, while the +5V6 is still stable. This
enables the microprocessor to take actions for a save shutdown (e.g. mute,
reset of electronics, release of head support of tape deck).
Amplifier part
+12V-regulator
Is used to supply all motors (+12M) and all analog circuits (+12A) in the set.
+12C is provisional only.
• Power on/off:
Switching on/off is done via the STBY-line from the microprocessor. H=ON,
L=OFF. If the STBY line is high, transistor 7222 is conductive. The base of
7224 becomes less positive than the emitter. This causes transistor 7224 to
switch through and supply the base of 7221. Consequently 7221 swiches
trough as well. Via 3218 transistor 3228 is conductive as soon as B2 is
available. Consequently switching transistor 7227 is also switched through.
If the STBY line is switched to low level, base current for 7222 is blocked. In
turn 7224 and 7221 are blocked, and power is turned off.
• Regulation:
Key components are power transistor 7221, reference diode 6221, and
transistor 7223. After power is switched on via the STBY line as described
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above, the +12A increases until 7223 becomes conductive via reference
diode 6221. 7223 reduces the base current of 7221 and +12A is stable
(typical +12,4V). In normal operating mode 7227 is always switched through
as described above.
• Protections:
In case of overcurrent (typically 2,5A), 7227 goes out of saturation, 7226
becomes conductive, 7225 becomes conductive via 6225, 7228 is blocked
(no base current any more), and 7227 is blocked too (no +12V). Restarting
is only possible by turning power off, then back on.
In case of overvoltage (more than +15V on emitter of 7221), 7225 is now
activated via 6233, 7228 is blocked (no base current any more) and 7227 is
blocked too (no +12V).
These protections are implemented for saving the set electronics in any fault
condition.
-30V regulator
• Grid supply for the FTD is switched by the microprocessor (simple regulation
with 6251 as reference; typical value: -29V; maximum current: 30mA).
VCD supply:
Is a provision for versions with a Video CD Player.
This circuitry consists of a switched supply with a regulator to 5,1V (±0,15V).
• Switching on/off is done via the VCD_ON line from the microprocessor
(H=on, L=off). If the VCD_ON line is high, transistor 7236 becomes
conductive. This causes transistor 7238 to switch through. +5VCD is
available. If the VCD_ON line is low, transistor 7236 is blocked, there is no
base current through 7238 so transistor 7238 is blocked too and +5VCD is
switched off.
• Regulation is done via Z-diode 6244 and transistor 7237. If the +5VCD
exceeds 5,1V, the base of transistor 7237 becomes higher than 0,6V via
Z-diode 6244. Consequently transistor 7237 becomes conductive. This
causes a reduced base current through 7236. Transistor 7236 becomes less
conductive and reduces the base current trough 7238. Transistor 7238
becomes less conductive too and reduces the +5VCD.
Amplifier:
Caution: In the POWER 4 module the power amplifier IC (AN7164) is used as
a bridge amplifier. Any connection from output to ground will destroy the
outpout stages.
• Via the AMP_ON control line, connected to pin 6 (Stby), the power
amplifiers are switched on/off by the microprocessor:
High level (approximately 4,5V): power amplifiers switched on
Low level (approximately 0V): power amplifiers switched off
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• Super class G operation
The power amplifiers operate as so-called super class G - amplifiers:
The supply pins 12 (Vcc) are not just connected to one fixed DC supply as in
conventional amplifiers. Dependent on the output power, there are three
different DC voltages supplied to the power amplifiers:
+C (+18V) for low output power
+B (+25V) for medium output power
+A (+36V) for high output power
Principles / benefits of Super Class G
Display Super Class G Output Benefits
• advantages: - best efficiency
- less power drawn from the mains transformer than by
conventional operating amplifiers reduces transformer
heating
- reduced power dissipation at the amplifier ICs results in
• less junction temperature and better reliability
• possibility of higher output power with smaller cooling fin
• smaller size
• Functional description of super class G circuitry used in the Power 4 module
The DC level on the amplifier output pins is normally Vcc/2. With low signals,
+C is supplying the amplifiers via decoupling diode 6312. The DC level on the
output pins is therefore approximately 8,6V and there is approximately 8V on
the base of 7315. When the output signal increases, the DC level on the base
of 7315 increases via diodes 6305, 6306, 6307, and 6308. At a certain output
power, 7315 becomes slightly conductive and enables low base current for
7304, which becomes conductive too and pulls the gate of FET 7303 up to a
more positive level. Thus FET 7303 begins to switch through and connects the
higher DC supply +B1 slowly to the power stages.
This does not end up in hard switching but in smooth regulating, because Vcc
is coupled back to the emitter of 7315 via zener diode 6310. As soon as Vcc
increases, the level on emitter 7315 is increased by a 3,9V lower level than
Vcc. When the output power is increased further +B1 would not be high
enough to enable undistorted output signal. The more the output level
increases the more the DC level on base of 7315 increases, which causes the
transistor to conduct more and more until the summary of the voltage drop on
3340+E/B 7304+3342 becomes approximately 1,4V. Now the necessary VBE
for a darlington-type transistor is obtained, 7305 begins to switch through and
connects the again higher DC supply +A slowly to the power stages. 7305
regulates +A, the same as described before for +B.
7322 and 7316 switch the ripple capacitor 2355, dependent on the output
power. With low output power the DC level on base 7322 is approximately 8V.
Via zener diode 6310 and resistor 3333 the emitter is pulled to Vcc (+C at low
levels). 7322 is switched through and in turn 7316. The ripple capacitor 2325
is connected to ground and functions as in normal amplifiers. Hum is
suppressed and good S/N-ratio is guaranteed even during silent music
passages.
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When the supply voltage has to be switched to a higher level, the DC level of
the ripple capacitor has to increase in the same relation, otherwise the
reference voltages inside the IC would not fit to the actual Vcc. Because of the
different delays this relation cannot be obtained and a continuously connected
capacitor to the ripple input would cause distortion. For that reason the ripple
capacitor 2325 is disconnected as soon as the output power exceeds a certain
value. When the output signal increases, also DC level on the base of 7322
increases via diodes 6305, 6306, 6307, and 6308. 7322 blocks and in turn
7316. The ripple capacitor 2325 is disconnected from ground. The circuitry is
designed so that 2325 is disconnected just before 7303 begins to switch +B
through (see above).
• For Center/Surround amplifier the function of the Super Class G circuit is
similar. Instead of +B1 there +B2 is connected.
• For the /37 versions with two channel application the so-called MATRIX
SURROUND is added. The 2 surround speakers are added in a way that in
case of STEREO a high signal can be measured (up to 10W per speaker at 6
ohms). In MONO only a few 100mW are available. Result: The widening of
the STEREO base is increased without any additional electronics or
amplifiers.
• In all four channel versions a preamplifier output for SURROUND is
available to add a wireless speaker system (e.g., FB206, FB208).
AF8 Board Brief Introduction
The AF8 Board consists of the following features:
a. TDA7437 IC
The TDA7437 (7511) audio processor IC includes functions such as source
selection, loudness, dynamic bass control, treble control, front/rear volume
control and a muting function. Sound features such as DBB, DSC, and IS
are controllable via I2C bus. All input sources are used, namely CD,
TUNER, TAPE, AUX, and differential input. Mono input is unused, and
terminated to ground via a capacitor.
b. MIC. MIXING
The AF8 Board can provide simple karaoke (without echo) which caters for
mic. mixing with additional mic. amplifier board.
c. LINE OUT
Line out cinch is included for connection to external devices such as
amplifier, recorders, etc.
d. SUB-WOOFER OUT
Sub-woofer out cinch is included for connection to active sub-woofer
speaker.
e. INCREDIBLE SURROUND
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Incredible surround effect using transistor circuitry to create phase shifting
and spatial effects.
f. HEADPHONE AMPLIFIER
A headphone can be driven by op-amp NJM4556AM.
g. CD STANDBY CONTROL
Control circuit that switches on the supply to CD servo control IC, HF
circuit, and the laser light pen in CD mode only.
h. HEADPHONE SENSING
Headphone sense circuit is for switching off DPL modes when headphone
is plugged in.
i. ATTENUATION NETWORK
This is provided at the output of the AF8 Board for interfacing with power
modules.
j. BASS AUTOMATIC LEVEL CONTROL (ALC)
This circuit will defeat the bass effect if it senses that there is an excessive
amount of bass frequencies present in the left and right audio channel. This
will prevent excessive speaker excursions under high volume conditions.
k. SURROUND OUT
Surround out cinch is included for Dolby Prologic versions when AF8 Board
is used together with DPL PCB MINI 2000.
Cassette Board Brief Introduction
General
1. Playback Mode
Signals from the playback head Deck A or Deck B are selected and fed
through by the Mode Selector IC7710 (HEF4952BT). The signal is amplified
by amplifier IC7720 (AN7323S) before feeding to IC7740 (HEF4952BT) and
out to the AF Board via connector 1701.
2. Recording Mode
Recording Signal is selected and fed through by the Mode Selector IC7710
(HEF4952BT) which is then amplified by the amplifier IC7720 (AN7323S).
The amplified output signal will pass through IC7730 (HEF4952BT) for
record equalization and back to IC7710 (HEF4952BT) before being
registered into the Rec./PB Head of Deck B.
3. Dubbing Mode
In Dubbing Mode, signal from the playback head Deck A is selected and fed
through by the Mode Selector IC7710 (HEF4952BT) which is then equalized
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for playback mode by the amplifier IC7720 (AN7323S) so that a flat
response is obtained after the preamp. The equalized signal will then follow
the same path as in the recording mode.
4. Mode Selector
The Mode Selector IC7710 (HEF4952BT) caters for 4 input signals, namely
Playback Signal from Deck A, Playback Signal from Deck B, Recording
Signal, and Dubbing Signal.
5. Amplifier PB/REC
Amplifier IC7720 (AN7323S) is for the purpose of amplifying the Playback
and Recording signal from the Mode Selector.
6. Automatic Level Control (ALC)
ALC circuit consists of resistors (3760, 3765, 3766, 3767), capacitors (2762,
2763) and control by transistor 7787 (BC847B). ALC limits the amplifier
output to a constant value when input signal becomes too large, thus
limiting recording current to below saturation levels, to prevent recording
distortion.
7. Muting Circuit (For Non-Dolby version only)
Switch S4 of the IC7740 (HEF4952BT) is for the purpose of muting the
output during Recording Mode. During Recording Mode, S4 is closed and
shorted to ground.
8. IC7740 (HEF4952BT)
The function of IC7740 (HEF4952BT) is to change the time constant
between 120us Ferro (IEC I) and 70us Chrome (IEC II) during playback
mode. It will automatically determine whether the tape type is 120us Ferro
(IEC I) or 70us Chrome (IEC II). This IC will switch to Flat Gain during the
Recording Mode.
9. IC7730 (HEF4952BT)
The function of IC7730 (HEF4952BT) is to change gain and time constant
according to tape type and recording speed to boost recording current at
higher frequency during recording to compensate for head loss. It will
automatically determine whether the tape type is 120us Ferro (IEC I ) or
70us Chrome (IEC II).
10. Bias Level
Bias Level makes use of variable resistor (3773) for adjusting the optimal
level of the bias current for Ferro or Chrome.
11. Bias Symm (For Dolby B NR version only)
Bias Symm makes use of variable resistor (3785) to adjust the bias current
for the left and the right channel to be equal.
12. PB Switch
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Playback Switch, which consists of the FETs 7785 (For Dolby B NR version
only) and 7786 (J111), is for the purpose of providing a virtual ground for
the Rec./PB Head (Deck B) during Playback Mode. During the Playback
Mode, the FETs are turned on and short pins two and four of connector
1720 to ground. During Recording Mode, the FETs are turned off to allow
the oscillator signal to be superpositioned onto the Recording signal for
recording.
13. Motor Speed (For FR versions only)
During high speed dubbing, a feedback signal from the uP through pin 03 of
the IC7610 (HEF4094BT) will trigger the transistors 7622 (BC847B) and
7616 (BC857B) to cause a change in the voltage level between high and
low, thus changing the speed of the motor.
14. IC7610 (HEF4094BT)
IC7610 (HEF4094BT) is a Shift Register used to issue the logic for CMOS
switch ICs (HEF4952BT) via 1A0, 2A1, and 2A2. It also issues logic to
On/Off SOL_A, SOL_B, and MOT. Recording speed is controlled via
NS/HS.
Dolby Circuit (For sets with Dolby B NR version only)
15. IC7630 (CXA1551M)
IC7630 (CXA1551M) in the Dolby circuit is a Dolby Noise Reduction Type B
IC for the Playback and Recording signal. Noise Reduction ON/OFF are
controlled by DOLBY, which is from CLK, direct from uP. After clocking in
DATA, CLK is set to HIGH/LOW for NR OFF/ON.
16. 19kHz Filter
The 19kHz filters 5631 and 5632 (LXD-210) in the Dolby circuit are for the
purpose of filtering the 19kHz Pilot Tone (for Tuner signal only) of the
Recording signal.
17. Level Adjust
The variable resistors 3635, 3636, 3641, and 3642 in the Dolby circuit are
for adjusting the playback level of the Dolby reference (400Hz, 200nWb/m).
Transistors 7631, 7632 are ON to enable adjustment of 3641, 3642 while
using Playback Deck A. Transistor 7633, 7634 and 3635, 3636 are active for
Playback Deck B.
18. Amplifier IC7640 (NJM4560M)
The amplifiers 7640A and 7640B (NJM4560M) in the Dolby circuit are for
the purpose of amplifying the Recording signal.
19. Muting Circuit
The muting circuit, which consists of transistors 7788, 7789, and 7790 (BC847B),
is for the purpose of muting the output during Recording mode.
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NOTATIONS AND ABBREVIATIONS USED IN THIS DOCUMENT
CR Chrome (IEC type II)
DB Dolby NR type B
DD Double Deck
DM Double Motor
FE Ferro (IEC type I)
FF Non-Autoreverse
FR Autoreverse Deck B
Gnd x Ground x
HSD High speed dubbing
ND Non-Dolby
NR Noise Reduction
NSD Normal speed dubbing
PB Playback
REC Record
S/A Sub-assembly
SD Single Deck
SM Single Motor
Cassette Options / Variants Table
MODULE ETF7
VARIANT 1 2 3
FEATURES DB/DD/FR ND/DD/FR ND/DD/FF
Deck configuration double double double
Deck type (Tokyo Pigeon) CWE CWE CWE
Auto-reverse yes (B) yes (B) no
Auto Replay no no yes (A+B)
Motor configuration single single single
Auto tape type selection yes yes yes
Dolby type B Noise Reduction yes no no
19 kHz pilot suppression yes no no
Normal / High speed dubbing yes yes no
Cue/Review and Fwd/Rewind yes yes yes
DB = Dolby B NR
DD = Double Deck
FF = Non-Autoreverse
FR = Autoreverse Deck B
ND = Non-Dolby
SD = Single Deck
Variations table for Analog Circuit
Autoreverse Non-autoreverse
ND/DD/FR ND/DD/FF
2701 , 2702 150pF 270pF
2703 , 2704 100pF 220pF
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CONNECTOR 1701 INTERCONNECTION TO AF BOARD
1 REC-L Record input left
2 REC-R Record input right
3 GND A AF Ground
4 TAPE-L Playback output left
5 +12V DC supply (+12V) for AF electronics
6 TAPE-R Playback output right
7 -CMOS Negative dc supply (-9V) for CMOS ICs
CONNECTOR 1703 INTERCONNECTION TO AF BOARD
1 GND M Motor Ground
2 +MOTOR DC supply (+12V) for tape deck motor and
solenoid
CONNECTOR 1706 INTERCONNECTION TO FRONT
BOARD
1 AD2 Deck sensing switches output voltage /
Deck A EOT
2 AD1 Deck sensing switches output voltage /
Deck B EOT
3 +5V DC supply +5V for ADC network
4 GND P Control and Oscillator Ground
5 CLK HEF4094BT shift register Clock line
6 DATA HEF4094BT shift register Data line
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7 STROBE HEF4094BT shift register Strobe line
CONNECTOR 1710 DECK B HEADS CONNECTON
(Non-Dolby version only)
1 B R/P HD L+ R/P Head left channel positive
2 GND A R/P Head return ground
3 B R/P HD R+ R/P Head right channel positive
4 ERASE HEAD Erase Head
5 GND A Erase Head ground
CONNECTOR 1720 DECK B HEADS CONNECTON
(Dolby B NR version only)
1 B R/P HD L+ R/P Head left channel positive
2 B R/P HD L- R/P Head left channel negative
3 B R/P HD R+ R/P Head right channel positive
4 B R/P HD R- R/P Head right channel negative
5 ERASE HEAD Erase Head
6 GND A Erase Head ground
CONNECTOR 1730 DECK A HEAD CONNECTIONS
(Double Deck versions only)
1 A PB HD L+ Pb Head left channel positive
2 GND A Pb Head return ground shield
3 A PB HD R+ Pb Head right channel positive
CONNECTOR 1740 DECK A AND B CONTROL INTERFACE
(Dolby B NR version only)
1 REC REW Record tab protection status switch
(reverse) [open=on: close=off]
2 CrO2 B Chrome tape detection switch deck B
[open=Cr: close=Fe]
3 REC FWD Record tab protection status switch
(forward) [open=on: close=off]
4 PHOTO B Photo sensor output (tape movement
indication)
5 SOL B Solenoid supply for deck B
6 Vcc Deck / Motor supply
7 MODE B Mode switch (head engagement)
[open=off: close=engaged]
8 GND M Deck / Motor ground
9 SOL A Solenoid supply for deck A
10 PHOTO A Photo sensor output (tape movement
indication)
11 MODE A Mode switch (head engagement)
[open=off: close=engaged]
12 L L pin for motor
13 CrO2 A Chrome tape detection switch deck A
[open=Cr: close=Fe]
14 H H pin for motor
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CONNECTOR 1770 DECK A AND B CONTROL INTERFACE
(Non-Dolby version only)
1 REC REW Record tab protection status switch
(reverse) [open=on: close=off]
2 CrO2 B Chrome tape detection switch deck B
[open=Cr: close=Fe]
3 REC FWD Record tab protection status switch
(forward) [open=on: close=off]
4 PHOTO B Photo sensor output (tape movement
indication)
5 SOL B Solenoid supply for deck B
6 Vcc Deck / Motor supply
7 MODE B Mode switch (head engagement)
[open=off: close=engaged]
8 GND M Deck / Motor ground
9 SOL A Solenoid supply for deck A
10 PHOTO A Photo sensor output (tape movement
indication)
11 MODE A Mode switch (head engagement)
[open=off: close=engaged]
12 L L pin for motor
13 CrO2 A Chrome tape detection switch deck A
[open=Cr: close=Fe]
14 H H pin for motor
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Overall Block Diagram
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Tuner Block Diagram, EC05 Tuner
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Tape Module Block Diagram
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CD Block Diagram
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Power 4-99 Two Channel Module
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circuit diagram
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Display +B2 Supply Voltage Generation
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Display +C Supply Voltage Gereration
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Display Simplified +C Generation
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Display Super Class G Output Benefits
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Philips Consumer Electronics
Technical Service Data
Service and Quality
Service Publications Dept.
One Philips Drive
P.O. Box 14810
Knoxville, TN 37914
Manual 1970
Model no.: FWC80C37
First Publish: 08-02-00
Rev. Date: 04-05-2005
Print Date: 05.04.2005
Parts List
REFER TO SAFETY GUIDELINES
SAFETY NOTICE: ANY PERSON ATTEMPTING TO SERVICE THIS CHASSIS MUST FAMILIARIZE
HIMSELF WITH THE CHASSIS AND BE AWARE OF THE NECESSARY SAFETY PRECAUTIONS
TO BE USED WHEN SERVICING ELECTRONIC EQUIPMENT CONTAINING HIGH VOLTAGES.
CAUTION: USE A SEPARATE ISOLATION TRANSFORMER FOR THIS UNIT WHEN SERVICING