background image
DECEMBER 1999
No. 0104
CP2155TA
SERVICE MANUAL
WARTUNGSHANDBUCH
CAUTION
CAUTION
::
Before servicing this chassis, it is important that the service technician read
the "Safety Precautions" and "Product Safety Notices" in this service manual.
VORSICHT :
VORSICHT :
Vor Öffnen des Gehäuses hat der Service-Ingenieur die ,,Sicherheitshinweise"
und ,,Hinweise zur Produktsicherheit" in diesem Wartungshandbuch zu lesen.
Data contained within this Service
manual is subject to alteration for
improvement.
Die in diesem Wartungshandbuch
enthaltenen Spezifikationen können
sich zwecks Verbesserungen
ändern.


background image
1
ENGLISH ..............................................................................................................................................................2
SAFETY ...........................................................................................................................................................2
SAFETY PRECAUTIONS ............................................................................................................................................. 2
SAFETY AND ISOLATION .......................................................................................................................................... 3
USER GUIDE ..................................................................................................................................................4
OPERATING INSTRUCTIONS..................................................................................................................................... 4
CIRCUIT DESCRIPTION.................................................................................................................................6
SWITCHED MODE POWER SUPPLY.......................................................................................................................... 6
TUNER and IF STAGES................................................................................................................................................ 7
SOURCE SELECTION .................................................................................................................................................. 8
COLOUR DECODER .................................................................................................................................................... 9
HORIZONTAL and VERTICAL DEFLECTION .......................................................................................................... 10
TUBE-BASE PANEL................................................................................................................................................... 11
AUDIO DEMODULATION AND POWER AMPLIFIER............................................................................................. 12
REMOTE CONTROL .................................................................................................................................................. 13
MICROPROCESSOR CONTROL SYSTEM................................................................................................................ 14
SERVICEING................................................................................................................................................. 15
ADJUSTMENTS ......................................................................................................................................................... 15
DEUTSCH ........................................................................................................................................................ 17
SICHERHEIT................................................................................................................................................. 17
SICHERHEITSVORKEHRUNGEN ............................................................................................................................. 17
SICHERHEIT UND ISOLIERUNG.............................................................................................................................. 18
BEDIENUNGSANLEITUNG .......................................................................................................................... 19
BETRIEBSVORSCHRIFTEN ...................................................................................................................................... 19
SCHALTUNGSBESCHREIBUNG................................................................................................................... 21
SCHALTMODUS STROMVERSORGUNG ................................................................................................................ 21
TUNER und ZF-STUFEN ............................................................................................................................................ 23
QUELLEN-AUSWAHL............................................................................................................................................... 24
FARBDECODER......................................................................................................................................................... 25
HORIZONTALE UND VERTIKALE DEFLECTION................................................................................................... 26
Die CRT-Trägerplatte................................................................................................................................................... 27
AUDIO DEMODULATION UND LEISTUNGSVERSTÄRKER.................................................................................. 28
FERNSTEUERUNG .................................................................................................................................................... 29
MICROCONTROLLER STEUERUNGSSYSTEM....................................................................................................... 30
WARTUNG .................................................................................................................................................... 31
EINSTELLUNGEN...................................................................................................................................................... 31
PARTS LIST / STÜCKLISTE........................................................................................................................... 33


background image
2
Engl
Engl
ish
sh
SAFETY
SAFETY
SAFETY PRECAUTIONS
SAFETY PRECAUTIONS
WARNING: The following precautions must be observed.
ALL PRODUCTS
1.
Before any service is performed on the chassis an
isolation transformer should be inserted between
the power line and the product.
2.
When replacing the chassis in the cabinet, ensure
all the protective devices are put back in place.
3.
When service is required, observe the original lead
dressing. Extra precaution should be taken to
ensure correct lead dressing in any high voltage
circuitry area.
4.
Many electrical and mechanical parts in HITACHI
products have special safety related
characteristics. These characteristics are often not
evident from visual inspection, nor can the
protection afforded by them necessarily be
obtained by using replacement components rated
for higher voltage, wattage, etc. Replacement
parts which have these special safety
characteristics are identified by marking with a
!
on the schematics and the replacement parts list.
The use of a substitute replacement component
that does not have the same safety characteristics
as the HITACHI recommended replacement one,
shown in the parts list, may create electrical
shock, fire, X-radiation, or other hazards.
5.
Always replace original spacers and maintain lead
lengths. Furthermore, where a short circuit has
occurred, replace those components that indicate
evidence of overheating.
6.
Insulation resistance should not be less than 2M
ohms at 500V DC between the main poles and
any accessible metal parts.
7.
No flashover or breakdown should occur during
the dielectric strength test, applying 3kV AC or
4.25kV DC for two seconds between the main
poles and accessible metal parts.
8.
Before returning a serviced product to the
customer, the service technician must thoroughly
test the unit to be certain that it is completely safe
to operate without danger of electrical shock. The
service technician must make sure that no
protective device built into the instrument by the
manufacturer has become defective, or
inadvertently damaged during servicing.
CE MARK
1.
HITACHI products may contain the CE mark on
the rating plate indicating that the product contains
parts that have been specifically approved to
provide electromagnetic compatibility to
designated levels.
When replacing any part in this product, please use only the
correct part itemised in the parts list to ensure this standard
is maintained, and take care to replace lead dressing to its
original state, as this can have a bearing on the
electromagnetic radiation/immunity.
PICTURE TUBE
1.
The line output stage can develop voltages in
excess of 25kV; if the E.H.T. cap is required to be
removed, discharge the anode to chassis via a
high value resistor, prior to its removal from the
picture tube.
2.
High voltage should always be kept at the rated
value of the chassis and no higher. Operating at
higher voltages may cause a failure of the picture
tube or high voltage supply, and also, under
certain circumstances could produce X-radiation
levels moderately in excess of design levels. The
high voltage must not, under any circumstances,
exceed 29kV on the chassis (except for projection
Televisions).
3.
The primary source of X-radiation in the product is
the picture tube. The picture tube utilised for the
above mentioned function in this chassis is
specially constructed to limit X-radiation. For
continued X-radiation protection, replace tube with
the same type as the original HITACHI approved
type
4.
Keep the picture tube away from the body while
handling. Do not install, remove, or handle the
picture tube in any manner unless shatterproof
goggles are worn. People not so equipped should
be kept away while picture tubes are handled
LASERS
If the product contains a laser avoid direct exposure to the
beam when the cover is open or when interlocks are
defeated or have failed.


background image
3
SAFETY AND ISOLATION
SAFETY AND ISOLATION
Under no circumstances should any form of repair or
maintenance be attempted by any person other than a
competent technician or engineer. Most of the circuitry on
the chassis is isolated from the AC supply by T801, C831,
R821, IC802 and 6mm air gaps. To maintain this safety
factor ensure that, after repair, any gaps or leakage paths
are not reduced by protruding wires etc., following
component replacement
NOTE: although the output supply paths from the power
supply section are isolated from the incoming AC supply, the
bridge rectifier and the control and regulation circuits are not
isolated. Therefore, when servicing the power supply section
of the chassis, the AC supply should be connected via an
isolating transformer of at least 200 watts rating.
The power supply section remains charged with respect to
chassis for 30­60 seconds after switching off. Care should
be taken to avoid touching the power supply area of the
chassis during this time.
Components marked
! in the parts list are safety approved
types and should be replaced only with components supplied
or approved by our Service Department. It is also
recommended that components not marked with the safety
symbol should be replaced with parts of the type originally
fitted. This applies particularly to those resistors which are
`stood off' the printed circuit boards.
Chassis Operation and Alignment
The majority of chassis functions are implemented within
IC504 and its associated circuitry. These are controlled by
the micro-controller IC701 via the I²C bus, a two wire bus
(SDA, Serial Data and SCL, Serial Clock). The micro-
controller contains twenty adjustable parameters between
00­13 (hex) which are used to control the functions of IC504
. (
See Adjustments for further details on how to adjust or reset
these.)
Handling Precautions - Static Electrical Charge
The receiver contains devices which may be damaged by
static electrical charges during handling. To avoid damage,
soldering irons should be earthed, and service personnel
should, ideally, wear wrist straps earthed through a 1M ohm
resistor. If the latter is not practical, they should discharge
themselves by touching an earthed point. Sensitive static
devices should be packed in suitable conductive containers.
IMPORTANT: although the receiver chassis is isolated, the
AC supply should be disconnected during service
replacement of such static devices.


background image
4
USER GUIDE
USER GUIDE
OPERATING INSTRUCTIONS
OPERATING INSTRUCTIONS
Switching On.
The television powers up into its last operating state, i.e. `On'
or `Standby'. If the television is in standby press any numeric
key or the TV key
b on the hand unit to switch on.
Tuning
Automatic tuning may be performed from the `SETUP' menu.
(
See "Automatic Tuning" below).
Manual tuning and Fine tuning may be performed from the
`MANUAL' menu.
(See "Manual Tuning" below).
Menus
Menus are selected using the coloured keys: RED for Audio
controls, GREEN for Picture controls, YELLOW for
Programme controls (tuning related) and CYAN for Features
To select an item from a menu use the
' key to move the
cursor (highlighted block) upwards or
$ to move it down
To adjust the selection use the
% or & key to decrease or
increase the setting accordingly. These keys also perform
the function of moving the cursor left or right when required
to do so.
Normally, to leave a menu and return to TV viewing press
the TV key
b.
Programme Menu
Press the YELLOW key - This gives an overview, in tabular
form, of all sixty programme locations.
For each of the sixty programme locations the programme
number will be displayed followed by the programme name,
four red dashes or four white dashes. The red dashes signify
that no programme has been tuned and stored there, whilst
the white dashes signify a programme has been tuned and
stored in that location during automatic tuning.
Use the
%, &, ' or $ keys to select a programme.
Note: only thirty programmes can be displayed on the screen
at a time, either programmes 0 - 29 or 30 - 59. Use
% or &
key to change the display as necessary.Set-up Menu
From the Programme menu press the YELLOW key to select
SETUP menu.
Automatic tuning.
To automatically tune all TV stations press the CYAN key
from the SETUP menu. This causes the TV to find all
stations and assign them to individual programme locations.
Note: Whilst automatic tuning is taking place it can be
cancelled by pressing the CYAN key; this will abandon all
the stations tuned since the automatic tuning was initiated.
Manual tuning
To manually tune TV stations press the GREEN key from the
SETUP menu. This allows TV stations to be tuned and
stored in any programme location 0 - 59.
TUNE - for manual tuning up or down the band, depending
on whether the
% (down) or & (up) key is pressed, and
automatically defeat of automatic frequency control (AFC).
SEARCH - this initiates a search for the next TV station
down or up the band depending on which key is pressed,
%
(down) or
& (up). If AFC has been defeated by manual
tuning then AFC will be re-applied to tune the current station.
BAND - the band may be changed using this option,
although the switch is not made until search or manual
tuning is made.
STORE - this is used to save the current tuning information,
including AFC defeat indication and band etc., for the
selected programme.
Audio Menu
To access audio controls press the GREEN key from the
SETUP menu.
From this menu volume, balance, treble, bass, sound mode
and spatial may be adjusted. If headphone option is present
and configured then headphone volume and balance may
also be adjusted
MODE - This allows the sound mode to be
changed, according to the type of broadcast or
external source that is available, to FM Mono, FM
Stereo, FM Dual Language I, FM Dual Language
II, AV Stereo ,AV Dual Language 1 and AV Dual
Language II.
Note: Not all modes are available simultaneously
Picture Menu
Press the GREEN key. Brightness, contrast, colour,
sharpness and hue (optional) may be adjusted.
STORE - this is used to save the new picture
settings.
Features Menu
Press the CYAN key. From this menu the source selection
may be changed, the child lock (local control buttons) may
be enabled/disabled and the sleep timer set/reset.
Sound Mode
Press the
3 key, when not in menu mode, to change
sound mode to mono, stereo, dual language I or dual
language II according to the type of broadcast.
Changing Picture Source
To select AV1, AV2, RGB or TV source for viewing (actual
sources available depend on the model), repeatedly press
the
2 key (when not in menu mode) until the appropriate
source is selected, as indicated in the top left corner of the
screen
(see "On-Screen Symbols" below). Alternatively, the
source may be changed from the features menu.
Text/Mix Modes
Pressing the
, key from TV picture mode selects TEXT
mode. Further depressions of this key toggles the TV
between TEXT and MIX modes.
To return to TV picture mode press the
b key.
Normalise
Press
L key, while not in menu mode, to set the
brightness, contrast, colour and sharpness controls to
approximately mid-position.
Status Display
An on-screen indication of the current programme number
and name, together with the status of various operating
modes are given when the
0 key is pressed (see "On-
Screen Symbols" below).