Toshiba L730 Laptop White Screen Repair

Laptop Model : Toshiba L730

Fault : White Screen On Startup

Repair Process:

There should be the following possibilities: screen, screen cable or screen power supply circuit. Of course, there is a problem with the graphics card, and this kind of white screen may also appear.

This possibility is relatively small, because after all, there is a boot sound (Experience: If this If the white screen is slightly bright at startup, and the hard disk light does not flash at all when power is turned on, then the graphics card is more likely. If the hard disk light keeps flashing, the fault is more extensive).

Let’s start with simplicity first. The same problem occurs after changing the screen. The test screen cable is normal (there is a picture below, with this small tool, it is very convenient to quickly judge the quality of the screen cable).

When testing the screen cable interface CN3 LCDVCC on the motherboard, the voltage is only 0.5 V, normally it should be 3.3V (the white screen means that the brightness turn-on signal is already there, and there should be LCDVCC 3.3V voltage).

Check the circuit diagram. This voltage comes from U17. U17 has power supply and turn-on signal, so this chip should be broken.

But if you don’t have this kind of chip on hand, you can also slightly change the circuit and directly connect pins 1 and 6 with flying wires. After powering on the machine, it lights up normally.

This has fixed the problem of white screens on many Toshiba L600 and L700 series. Generally, this chip is bad. Cause, if you don’t have this core on hand, connect it with a flying wire.

Happy Repairing !!