Philips FW-C50/37, Руководство по обслуживанию

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TRAINING INFORMATION
Block Diagrams
Overall Block Diagram
Tuner Block Diagram, EC05 Tuner
Tape Module Block Diagram, MTF Module
CD Block Diagram, 3CDC – LC Module
Circuit Descriptions:
Power 4-99 Module (2 Ch. Ver.)
Supply-part
General
(pos. numbers refer to circuit diagram)
The primary circuitry depends on the version:
• Versions with fixed primary voltage: 100V
AC
for /26
120V
AC
for /37
220-240V
AC
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 printed board respectively version table in circuit diagram or
partslist.
• Version with switchable primary voltage: 110-127/220-240V
AC
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 printed board respectively version table in circuit diagram or
partslist.
• 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.
In case power is switched on, the control line ECO is low >> relay 1208 is activated >> standby transformer
5211 is shortened and out of work.
When the set is switched off (standby) the control line ECO is high >> relay 1208 is not activated >> 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
mainsvoltage is divided by approx. 85% (standby transformer) to 15% (mains transformer). Thus the mains
transformer delivers very low secondary voltage >> power consumption is less than 100mW.
Via standby transformer and rectifiers 6209-6212 the supply vC is substituted. The 5,6V regulator is
still working and so the microprocessor is kept running.
• DC voA, +B1/+B2, +C
These voltages supply the Super Class G amplifier, described later in this chapter.
The whole power supply is optimized for the special characteristic 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.