Wednesday, 26 May 2021

SHARP 21V FS 700S COLOUR TELEVISION – how to enter the service mode, circuit diagram

 

Always respect voltages. While some may not be dangerous in themselves, they can cause unexpected reactions that are best avoided. Before reaching into a powered TV set, it is best to test the high voltage insulation. It is easy to do, and is a good service precaution.  It makes sense to avoid exposure to electrical shock.  While some sources are expected to have a possible dangerous impact, others of quite high potential are of limited current and are sometimes held in less regard.

When servicing the high voltage system, remove static charge from it by connecting a 10K ohm resistor in series with an insulated wire (such as a test probe) between picture tube dag and 2nd anode lead. (AC line cord should be disconnected from AC outlet.)
1) Picture tube in this receiver employs integral implosion protection.
2) Replace with the same type number of picture tube for continued safety.
3) Do not lift picture tube by the neck.
4) Handle the picture tube only when wearing shatterproof goggles and after discharging the high voltage completely.

Service mode entry method

Press and hold the local key “vol down” and  “channel up” when power on the main switch, TV will enter into the service mode in adjustment mode. (the initial value of the EEPROM are automatically preset when the new EEPROM is used).  Service mode also can be reached by pressing the service key (code: 40Hex)

Press the channel up or dn key on the remote controller to select the items one by one in adjustment mode.

Using the volume up or down key on the remote controller, the data can be modified.

When press the local key “Vol Down and Channel Up” at the same time, it will be released from the service mode.

Press the  Menu key on the remote control to enter into the NVM mode.  Press menu key again to leave the NVM mode return to adjustment mode.  (it is not recommended to modify the data unless as listed in BUS SETUP data)

Press both channel up and volume down buttons on the TV set simultaneously or press the “service”(40HEX) key again, it will switch to the normal mode position, and the microprocessor is out of service mode.

Default locking password “0000”

Factory presetting

Press remote controller key of code “ED” for  4 seconds, the initial values are automatically preset.

Make sure whether the data need to modify or not (initial data)

If haven’t done this initialization, malfunction might happen.

Below are the adjustment items that should be done, otherwise some adjustment items will not be accurate.





Schematic diagram and PWB





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