Panasonic EURO 4 Chassis Technical Manual page 145

3DQDVRQLF
Chapter 4
: Pin 55 - Service
PLEASE NOTE: Even though this following option is
still available when in Service Mode, the EAROM of
the EURO 4D Chassis is 32k bits and the Memory
Pack is only 16k bits. This means that the memory
pack is unable to store all the EAROM data.
The SERVICE output control line only goes high when
the TV is switched into Service Mode. The service
control line is used to allow a memory programmer
to be connected via AV1, allowing data to be
transferred between TV and memory programmer or
vice versa.
The programmer basically consists of an EAROM
which when connected to the AV1 socket, can talk
directly with the microprocessor IC1101 via the I
bus 1. Since pins 10 and 12 of the 21 pin AV1 socket
are available only during service mode, I
must be set to high impedance during all other
operating modes. This is achieved by disconnecting
2
the I C bus 1 from the 21 pin socket by means of two
transistors Q3006 and Q3007.
Transistors Q3006 and Q3007 are controlled via pin
55 of the microprocessor IC1101, which when the
Programmer function is called up in Service Mode, the
transistors are switched ON with a High level allowing
the transfer of programming data from the
microprocessor IC1101 to programmer or from the
programmer to microprocessor
mentioned earlier the transistors are switched OFF
with a Low level, thus switching pins 10 and 12 of AV1
socket to high impedance.
:
Pin 69 - LED IRD
The LED device D1012 located on the M-Board
incorporates two LEDS. One LED is used to display
TV standby, while the second is used to signal
operation of the DVB Decoder.
Control of the DVB LED is via pin 69 of the
microprocessor IC1101, which when in operation
feeds a LOW level to Q1013 on the M-Board. This
LOW level results in Q1013 switching ON and the
DVB LED is illuminated.
:
This control line output from pin 73 of the
microprocessor IC1101 is used as an interrupt control
line between the UART IC IC1107 located on the
T-Board the microprocessor IC1101 on the E-Board.
:
Output from pin 77 of the microprocessor IC1101 is
Geo-Magnetic Correction control, this is used for
large screen CRTs which is required to cancel the
effects of the earth's magnetic field.
:
2
The 4:3 RGB control output from the microprocessor
C
is used to support the display of an RGB picture on
2
wide screen TVs. This is achieved by mechanical
C bus 1
means as oppose software by transistor Q590 and
relay RL590. The 4:3 RGB control line being used to
control transistor Q590 responsible for controlling the
horizontal aspect ratio. Where the aspect ratio of the
picture is reduced to a 4:3 display the operating
voltage to the DAF circuit located on the W-Board has
to be reduced too, ensuring that the DAF correction
signal is also reduced to match the active picture scan
ensuring optimum picture conditions as described in
chapter 4 section 6.
IC1101. As
:
The standby LED is incorporated into a dual LED
device D1012 (located on the H-Board) which has two
LED's. One LED is used to display TV standby, while
the second is used to signal operation of the DVB
Decoder.
Control of the standby LED is via pin 81 of the
microprocessor IC1101, which when in standby mode
is set to a LOW level causing Q1011 on the M-Board
to switch ON, resulting in the standby LED to switch
ON. Pin 81 is also used to flash the standby LED when
the Infra-red remote control receiver receives a signal
from the remote control.
62
EURO 4D Supplement
Pin 73 - In
Pin 77 - G.M.C.
Pin 79 - 4:3 RGB
Pin 81 - LED