The tp.ms3458.pc757 uses dual firmware: SPI (bootloader) and NAND/EMMC (OS). Corruption is common.

If all voltages are pristine, the firmware inside the Flash IC is likely corrupted. You will need to desolder the chip and reflash it using an RT809F, RT809H, or CH341A programmer (see Section 5). Fault 3: Sound is Present, But No Picture (Screen is Black)

After swapping a motherboard or changing a screen panel, the image may appear upside down (mirrored) or have distorted colors (LVDS mapping issue). You can correct this via the hidden Factory Menu. Access Procedure: Turn on the television. Press the (or Input) button on the remote control.

Lowers the maximum software current to extend the life of the internal LED strips.

TP.MS3458.PC757 Service Manual: Comprehensive Troubleshooting and Repair Guide

The is more than a PDF—it’s a diagnostic roadmap. Without it, you are guessing. With it, you can methodically isolate a dead backlight to a failed boost converter, or a boot loop to a corrupt NAND.

Wait until the indicator light flashes rapidly, then remove the USB. 5. Identifying Key Components