Toshiba T6400DXC LCD Panel Backlight Replacement
This is part 3 of the Toshiba T6400DXC luggable PC repair series. Even after replacing all the leaking capacitors in the LCD panel there were still problems with it sometimes going dark after power on. This is caused by the aging fluorescent lamps that are used for the backlight.
Instead of trying to find replacement fluorescent tubes and dealing with the dangerous high voltage involved I choose to replace them with modern LED strips instead. On a trip to Japan I found some 15cm strips at Akiba LED that could work, which happens to run at 12V DC.
There are two additional circuit boards inside the T6400DXC screen besides the main panel itself. The board on the left is the inverter to generate the AC voltage for the fluorescent tubes, but the other one is a 24V to 12V converter. I was able to power the LED strip by using that power 12V supply directly:
After removing the old fluorescent tubes the LED strips can be placed as follows:
Both LED strips can be connected to the 12V supply board in parallel at this connector using Dupont connectors:
This is the end result, it is not perfect, but a whole lot better than a dark screen:
