Peter,
You will not be able to see anything on the display without the backlight. For TFT displays the backlight is a requirement.
The NHD-4.3-480272MF-34 controller board does have a voltage booster circuit, but the original circuit was designed to operate with the NHD-4.3-480272EF-ATXL# (Standard brightness display)
There is an option to power the backlight using your current board, but it will require some modification to the controller board.
1. You will need to replace the LED Driver on the controller board. This will be labeled U2, it is located right above the 40 pos FFC Connector for the display.
I recommend using a
FAN5333BSX2. You will need to swap the resistor on R45 with another resistor that is roughly ~7.8 Ω.
The LED driver will be able to produce the required voltage after these changes are made with a 3.3V input.
The parts i mentioned above are shown in the attached image.