Voltage Control back light

Backlight circuit problems are quite common. They are usually caused by connecting the LCD while the battery is still fully connected to the logic board.

However, there are several components in that circuit and the actual voltage controller has a lower incidence of failure than the rest of the circuitry. At any rate, repairing the circuit requires a certain amount of micro-soldering skills and specialized tools…it is not a DIY repair. You don’t say if you have those skills or experience but judging from the fact that a technician told you there was a logic board issue, I assume not (please correct me if I’m wrong).

The circuit really needs to be fully troubleshooted in order to determine what component has failed. Ordering electronics components parts can be more complicated depending on which part is required. Online sites like iFixit, MobileSentrix etc have the most common part.