More and more laptops come with LED backlights instead of the older CCFL. These are easier to control as they don’t need a high voltage inverter. So, for my Sinclair ZX Spectrum project, I’m going to replace the CCFL backlight with white LEDs.
Initially, I tried to reverse-engineer the CCFL inverter on the MITAC mainboard, but due to the many pins of the transformer in the inverter section and the multi-layer board, it’s not easy to extract a circuit diagram. Now, modern TFT’s come with LEDs anyway, so let’s replace the CCFL with white LEDs and thus modernize the TFT at the same time.
As a first step, I’ve disassembled the LCD panel. There are two main parts - the matrix with the 640 x 480 pixels with three circuit boards connected to it and a white, rectangular piece of plastic with the CCFL. The panel:
And the white plastic screen (as a ‘proof-of-concept’, I’ve used a pocket light to illuminat it):
Currently, I’m waiting for the white LEDs to arrive...