Sharp 28JS-74S – How to enter service mode – LED flashing codes – SMPS circuit diagram - NVM re-write

PAL/SECAM BG SYSTEM COLOUR TELEVISION - Sharp 28JS-74S – LED blinking codes – Service mode -  How to rewrite data in NVM – SMPS Schematic

SERVICE MODE
The Service Mode is provided to enable the engineer to correctly set up the receiver to the CRT fitted in the set.
Note that these adjustments may vary from one receiver to another.
To enter the Service Mode, carry out the following procedure.
1. Connect a test pattern to the antenna terminal.
2. Tune the receiver to this signal.
3. Turn the receiver off using the mains switch.
4. Press volume down and channel up buttons on the front of the receiver at the same time.
5. Keeping these buttons pressed, turn the mains on.
6. When the set starts up it will be in Service Mode.
7. Release the two buttons.
Use the channel up and down buttons to move between the options.
Use the volume control buttons to change the data.
To store the data, use the stand-by button on the remote control.
To exit the Service Mode, turn the receiver off using the mains switch.

When the Service Mode is entered the following On Screen Display appears
SERVICE SOFTWARE version ∗∗.∗∗
SW on: XXXX SW off: XXXX Hours ON: XXXX
The figures displayed in the “XXXX” locations are hexadecimal representations of the number of times that particular function has been executed. For example if the hexadecimal number displayed after “SW ON” was “0E4A”, this would correspond to the receiver being turned on 3658 times.
The following adjustments can be carried out in the Service Mode.
Horizontal Shift
East West Width
Pin Phase
Pin Amp
Upper corner correction
Lower corner correction
Extreme Corner Correction
Vertical Linearity
Vertical angle
Vertical bow
Vertical Amplitude
S Correction
Vertical Shift
Red Cut Off
Green Cut Off
Blue Cut Off
Alter NVM Pag (Page)
Alter NVM Pos (Position)
Alter NVM Val (Value)
Teletext Mix Mode Contrast
Teletext Contrast
OSD Contrast
DVCO Adjustment (Only PAL)
DVCO Adjustment (Only NTSC)
AGC Adjustment
Auto Installation On/Off

The following geometry adjustments can be carried out.

Horizontal Shift

East West Width

Pin Phase

Pin Amp

Vertical angle

Vertical bow

Upper Corner Amplitude

Lower Corner Symmetry

Extreme Corner Symmetry

Vertical Amplitude

S Correction

Vertical Shift

Vertical Linearity

Just in case the TV set requires a full geometry adjustment, please proceed first with Vertical according to the above order, and after that, adjust Horizontal according to the above order.

LED FLASHING CODES

If the TV set does not work and the power indicator is flashing, follow the sequence according to the information to fault finding.

> Unable to read or write into NVM: 66% ON, 33% OFF twice and OFF for a second.

> MSP failure: 66% ON, 33% OFF for three times and OFF for a second.

> SDA 9380 failure: 66% ON, 33% OFF for four times and OFF for a second.

> SDA 9402 failure: 66% ON, 33% OFF for five times and OFF for a second.

SMPS SCHEMATIC (Split and Full)

How to retrieve the IC6002 (Flash Memory).

Desoldering the Shield Case Cover.

Introduce the screwdriver through the hole.

Insert the screwdriver between the IC6002 and its socket. Push up the IC6002 with the screwdriver as in Figure 16.

Retrieve the IC6002.

How to retrieve the IC6002 with pincers (Flash Memory).
Desoldering the Shield Case Cover.
Introduce the pincers into the hole.
Insert the pincers and take hold the IC6002. Pick up the IC6002 with the pincers as in Figure 18.
Retrieve the IC6002

How to rewrite data in NVM.

The NVM (Non Volatile Memory) is a read/write device which function is to keep data even in the case of TV set is switched off.

Part of these data is recovered every time the TV is switched on, and, of course, if user makes any change in the user settings (i.e brightness, contrast, etc..).

The NVM data could be corrupted if any external destructive action is carried out (Sparks of high voltage) or if a problem happens to the IC itself (defective IC or damaged IC). In order to keep the data un-corrupted, several protection countermeasures are implemented; one of them is to have a copy of all the NVM relevant parameters in the FLASH (which keeps the software for the microcontroller). So, the procedure to follow if the NVM IC is damaged or the data is lost is the following:

a) If the NVM IC is substituted for a new (BLANK) one, it is possible to write the NVM asking for the file which corresponds to the model or let the microcontroller write the default data which is written inside. This process is automatically carried out when the blank device (NVM) is soldered and TV is switched on for first time after the modification. The TV starting time is longer than normally due to the rewriting procedure.  In both cases a new geometry adjustment should be done because of CRT and chassis tolerances.  

b) If the NVM is corrupted and some data is lost, there are internal software protection to recover the data related with configuration of ICs but user data can be lost (some channel data or user settings for video, audio etc..). It is possible to recover this data forcing an auto installation and setting the user settings again.