Wednesday, 3 February 2021

Daewoo DTA20, DTA21, DTE25, DTE28 - using IC TDA9367, STR F6653, using IC TDA9365, STR F6653 - How to enter the service mode

 

ATSS sorting method: The TV set sweeps all the TV bands from beginning of VHF to end of UHF. The TV controlling software for each program checks if a VPS CNI code is transmitted. If no VPS CNI code is found, the system check if a CNI code is transmitted in the teletext lines ( Packet 8/30 format 1 ). If such a code ( VPS or teletext ) is found and if this code is in the ATSS list, the program is automatically named.
The programs found are then sorted in 4 groups

Group I : It contains all the programs from the selected country and named by the TV controlling software. Within this group the sorting order is fixed by the ATSS list.
Group II : It contains all the programs with a strong signal strength which are not listed in group I.
Group III : It contains all the programs with a weak signal strength which are not listed in group I.
Group IV : If two or more programs with the same code are found, only the strongest ( or if they have the same level the one with the lowest frequency) is listed in group I, II or III. The others are listed in group IV.

Note : If two programs with the same name but a different code are found these two programs are listed in group I, II or III ( e.g. Regional program SW3 in Germany ).

The sorting order within group II, III, and IV is based on the channel frequency. The program with the lowest frequency is allocated the first rank in its group, and so forth until the last program of the group which has the highest frequency.

Special case : Country selection =  Others

Special case : France
If France is selected the TV controlling software sweeps the whole TV bands firstly with France system selected ( positive video modulation) and secondly with Europe system selected ( negative video modulation).

Special case : Switzerland
If Switzerland is selected the TV controlling software sweeps the whole TV bands firstly with Europe system selected (negative video modulation) and secondly with France system selected ( positive video modulation).

Special case : GB
Note for satellite receiver users : Before starting ATSS turn On your satellite receiver and tune “ SKY NEWS “.
If GB is selected the TV controlling software seeks for programs only in UHF ( C21 to C70 ). The sorting order is :
1 - BBC1
2 - BBC2
3 - ITV
4 - CH4
5 - CH5
6 – NEWS

If two or more “ identical “programs ( same name but different code e.g. BBC1 and BBC1 Scotland ) are found the following programs in the list will be shifted up. (1 - BBC1, 2 - BBC1, 3 - BBC2, 4 - ITV, 5 - CH4, 6 - CH5, 7 - NEWS, ..)

If one of the program above is not found, the associated program number remains empty ( freq.=467.25
Mhz - Skip selected - no name - system=GB).
example A : 1 - BBC1, 2 - BBC2, 3 - ITV, 4 - -----, 5 - CH5, 6 - NEWS, ...
example B ( if 2 BBC1 found ) : 1 - BBC1, 2 - BBC1, 3 - BBC2, 4 - ITV, 5 - -----, 6 - CH5, 7 - NEWS, ...

Alignment

Microcontroller configuration : Service mode
To switch the TV set into service mode please see instruction below.

1 - Select pr. number 91
2 - Adjust sharpness to minimum and exit all menu.
3 - Quickly press the key sequence :
RED - GREEN – menu

To exit SERVICE menu press menu key or Std By key.

In Service Mode press “OK” to stop the microcontroller i.e. the I2C bus is free and the set can be controlled by external equipment. Press “OK” again to allow the microcontroller to control the set again.

Data Capture: The Data Capture section takes in the analogue Composite Vidéo and Blanking Signal (CVBS), and from this extracts the required data, which is then decoded and stored in memory.

The extraction of the data is performed in the digital domain. The first stage is to convert the analogue CVBS signal into a digital form. This is done using an ADC sampling at 12MHz. The data and clock recovery is then performed by a Multi-Rate Video Input Processor (MuIVIP). From the recovered data and clock the following data types are extracted WST Teletext (625/525), Closed Caption, VPS, WSS.
The extracted data is stored in either memory (DRAM) via the Memory Interface or in SFR locations.

TDA894xJ Stereo Audio Amplifier

The TDA 8944J ( TDA 8946J ) is a dual-channel audio power amplifier with an output power of 2 x 7 W ( 2 x 15 W ) at an 8 W load and a 12 V supply. The circuit contains two Bridges Tied Load (BTL) amplifiers with an all-NPN output stage and standby/mute logic. The TDA8944J comes in a 17-pin DIL power package.

Daewoo schematic using IC TDA9365, STR F6653

Daewoo schematic using IC TDA9367, STR F6653


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