I recently picked up a Vizio E220VA LCD TV on ebay. It worked for two months and now doesn't power on. The PSU is getting 120V and no fuses are blown. The TV is unresponsive. No lights come on when the cord is plugged in as they usually did. I have searched and searched for a service manual for this TV and for a PSU circuit diagram. I cannot find either. Vizio will not send me anything either. Has anyone ever worked on these? I'm used to working on the Mitsubishi DLP TV's, but have never tried fixing an LCD. Any help is appreciated!!!!!
I'd start by checking the PSU output. Can you identify power rails? If so, you should see some volts. Any blown/bulging caps or other physical damage evident?
Thanks so much for the reply! I checked voltages from the connector that goes from the PSU to the main board. Voltages look normal. No bulging caps or visual wear on the PSU or main board. What is weird is I left the TV unplugged for four days or so. I plugged the TV back in and it started up and worked fine! I let it run an hour or so then unplugged it. After waiting a couple minutes I plugged it back in and nothing again. No power, no lights. What would cause thus condition?
I would guess there's a PSU fault; in particular a duff electrolytic cap in the PSU. Perhaps gone leaky (in the electrical sense)/dried out/high resistance?
Small value electrolytic caps in the primary/ feedback path are well known for start-up issues in switch mode supplies. Common values seen are 100uF, 22uF, 10uF, 4.7uF, 0.47 50/ 63V. As are start up supply resistors going high resistance. Check the supply rails the next time the TV fails to start up to rule out the power supply.
Check especially those electrolytics that find themselves next to a heatsink of some sorts. Replace them and use wires to move them away from those heatsinks. Glue them somewhere safe onto the board.