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Technical Guide
Colour Television
Euro-8 Chassis
Circuit Explanations
Panasonic European
Television Division
Matsushita Electric (UK) Ltd.
CONTENTS
1. Contents Page ..................................................................2
2. Introduction ..................................................................3
3. Wiring Block Diagram ....................................................... 4
4 Audio Block Diagram ........................................................5
5. Control Block Diagram ........................................................6
6. Power Supply Block Diagram .............................................7
7. Power Supply ...................................................................8
8. Horizontal Output ........................................................11
9. Microcontroller & Teletext Control ..................................13
10. Teletext Processing Stage .............................................17
11. Audio & Video Switching .............................................19
12. Digital Front End Tuning .............................................23
13. Vertical Output Stage .............................................24
14. Dynamic Automatic Focus .............................................25
15. Colour Output .............................................27
16. Audio Signal Processing .............................................28
17. MSP3410 .............................................29
18. Analogue Sound IF. .............................................31
19. NICAM Decoder .............................................33
20. Audio Output .............................................35
21. Dolby Prologic .............................................37
22. Digital Surround .............................................39
23. Encoding & Decoding .............................................40
24. Geomagnetic Correction .............................................47
-2-
Introduction .
This Technical Guide contains information for Euro- 8
We at Panasonic realize that the service engineer chassis and should be used in conjunction with the
needs to understand the circuitry inside the TV and relevant service manuals for this chassis.
for this need we have produced this Technical Guide
As a lot of the circuitry of the Euro-8 is the same as
some previous chassis some areas will not be dealt
with in the same depth as previous guides.
-3-
Wiring Diagram Panasonic
-4-
Audio Block Diagram
-5-
Control Block
-6-
Power Supply Block Diagram
-7-
Power Supply Unit
The STR-6656 is used in the Euro-8 power supply to
keep the I.R receiver, microcontroller, memory
control and regulate the power supply operation. This
devices, audio output IC's and AV Link circuitry
device features Over-Voltage protection and Thermal
operational during standby mode. These circuits
shut down. The output stage of the IC incorporates a
require a 5V supply during standby so as a switch on
built in MOSFET switching transistor. command from the remote controller or local keys
can be processed. This allows the switch ON of the
As well as the main power supply a standby power
TV receiver from standby, or in the case of the AV
supply is also used. The benefits of which result in a
Link circuit to process AV Link commands.
reduction in the power consumption when in standby
Only these areas deemed necessary to allow the TV
mode.
to react to the switch ON command in standby is fed
this 5V standby supply.This procedure allows low
power consumption to be achieved in standby mode.
Standby Power Supply Circuit
The standby power supply circuit which is situated on
the D-PCB, supplies 5V. This 5V is used to
Section Of D-PCB
-8-
The Euro-8 chassis has two power supplies D-PSU 6.5 Volts
the G-PSU. This is derived from pin 14 of T801 and is fed via
D851 to C853 from here it is out via pins 1&2 of
The power supplies of the Euro-8 chassis consists of socket G10 from here it is fed to the Z board and pins
standard power supply circuitry. 1 & 2.
The only difference is that it is contained on three
circuit boards as listed above. 33 Volts
This is derived from pin 11 of T801 and is fed via
D-PSU D852 to C855 from here it is out via pin 5 of socket
G10 from here it is fed to the Z board and pin 5.
137 Volt Rail
The 137V rail, is supplied via pin 21of T849 and fed IRD Voltages
via diode D895 and smoothing capacitors C894 &
893. 2.5 Volts
From here it is fed to the deflection circuitry and RGB The 2.5v IRD voltage is output from IC5806 pin 2 and
outputs on the L-PCB via D12 pin1. from there to socket Z3 pins 10 & 11.
42 Volt Rail 3.3 Volts
The 42 v rail is out from pin 15 and fed via diode The 3.3 v IRD voltage is output from IC5802 pin 2
D897 and then to the emitter of Q898 the resulting and from there to socket Z3 pins 7 & 8.
voltage is output from the collector and fed to the
sound output IC IC 251. 5 Volts
The 5v IRD voltage is output from IC5808 pin 4 and
9 Volt Rail from there to socket Z3 pins 14 & 15.
This is output from IC 3801 and fed to D2 pin 24 and
from there to Pin 24 plug A1 on the A-PCB 5v CI Volts
The 5 v CI voltage is output from IC5803 pin 4 and
from there to socket Z3 pins 24 & 25
8 Volt Rail
This is output from IC 3802 the 8 v regulator and fed 9 Volts
via pin 27 of D1 to pin 27 of H1 on the H-PCB The 9v IRD voltage is output from IC5804 pin 4 and
from there to socket Z3 pins 21.
3.3 Volt Rail
This is output from IC 3803 the 3.3 V regulator to pin 12 Volts
20 of socket D2 and from there to pin 20 of socket A1 The 12v IRD voltage is output from IC5805 pin 3 and
on the A-PCB. from there to socket Z3 pin 19.
2.5 Volt Standby 32 Volts
This is fed from pin2 of IC3806 the 2.5 volt regulator The 33v IRD voltage is output from C5803 and from
and fed to pin 26 of socket D2 from here to A1 pin 26 there to socket Z3 pin 17.
on the A-PCB
5 Volt Standby
The 5V standby is output from IC 3804 and from
there fed tp pin 22 of connector D2.
G-PSU
The G- Power Unit supplies the IRD voltages for the
digital processing side of the TV.
From the G-PSU there are supplied three voltages
10.5v 6.6v and 33v these supplies are fed to the Z-
PCB which contain the IRD regulators.
10.5 Volts
This is derived from pin 17 of T801 and is fed via
D850 to C862 from here it is out via pins 7&8 of
socket G10 from here it is fed to the Z board and pins
7 & 8.
-9-
G-PSU Schematic
- 10 -
Horizontal Output
Horizontal Driver
The line frequency pulses for the horizontal driver which is able to supply the necessary base control
stage are output from pin 8 of IC1701 and are fed to current for the driver transformer T501 of the output
the D-PCB via connectors A1