Vizio Y8389522A Main Board. This replacement main board is designed for Vizio 70 LED TVs that use part number Y8389522A. The main board handles video, audio, input processing and overall system control, and is often the cause of power-on with no picture or other signal-related issues. Part & Board Numbers. Partial Number on Sticker: 522 (may appear as part of the label). Board / Printed Numbers. Always match the part number and any matching board numbers from your original board. Matching only by TV model number may not be reliable. Vizio V705-J03 (LFTGD7KX serial). Other sets that use main board Y8389522A with the same board numbers may also be compatible. Common Symptoms of a Bad Main Board. TV powers on but has no picture. No HDMI or input detection, even when sources are connected. Stuck on logo, freezing, or continuous rebooting. No audio or distorted audio with a known good source. Intermittent operation or random shutdowns. These symptoms can sometimes be caused by other components as well, such as the power supply or panel. Proper diagnosis is recommended. Unplug the TV and allow several minutes for capacitors to discharge before servicing. Carefully disconnect and reconnect all ribbon cables and harnesses; ensure each connector is fully seated. Do not bend the board or force any connectors into place. Professionally inspected and tested for proper functionality. Guaranteed working replacement for the part and board numbers listed above. Please keep your original board until you confirm that the repair is successful. Securely packaged to protect the board during transit. Listing and template services provided by inkFrog.