28KF-84H (serv.man18) - Sharp TV Service Manual (repair manual). Page 77

The NVM (Non Volatile Memory) is a read/write device aimed to keep the data even in the absence of power. The
NVM contains IC configuration data, factory abjustable parametes (geometries, color temperature, etc.) and user
settings (video, audio, programs, etc.).

All data are recovered every time the TV is switched on, including last changes made by the user (brightness,
contrast, etc.).

If the NVM is corrupted and part of the data is lost, there are some internal software mechanisms to recover the
data, but some user data can be lost. It is possible to recover this user data forcing an auto installation and setting
the user settings again.

If the TV set is not working properly and the NVM is under suspician, the following procedure should be carried out
before replacing the NVM by a new one:

1. Enter Service Mode. See page 6.

2. Press the sound mode button (29) at the remote control. The screen will display “PLEASE, PUSH BLUE

BUTTON TO CONFIRM REWRITING NVM!”.

3. Press the blue button to rewrite the NVM or press any other button to cancel.

    

Once the blue button has been pressed, the text “REWRITING NVM, PLEASE WAIT” will be shown.

 After some seconds the TV set will automatically reset and the NVM will be filled with the default values.

If the NVM IC is substituted by a new (BLANK) one, it is possible to write the NVM asking for the file that corresponds
to the model or letting the microcontroller write the default data stored in Flash. This process is automatically
carried out  when the blank NVM is soldered and the TV set is switched on for the first time. 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.