Aug 28, 2018, 5:08 AM
Post #1 of 2
RCA LED46C45RQ Intermittent Power Issues
We're trying to figure out what's wrong with our RCA LED46C45RQ tv. The issue began when we noticed that occasionally the TV would not turn on when instructed by the remote or the power button. Sometimes a simple unplug and replug to the outlet would fix this issue temporarily, but it always comes back eventually. You can turn the TV off, but then you will be unable to turn it back on. In this state, we get a solid red standby light.
At this point, we decided to try to track down the issue internally. We removed the back panel and started probing the pcbs. After some testing, we've determined that the power board is fine. All the power busses show the correct values (0 V to all on standby except the standby 5 V and 5, 12, 24, etc volts when we short the standby pin to the on/off pin on the power supply). We can also short the 5V pin to the backlight on/off pin and manually force the backlights on. We also checked that the contacts from the on/off button to the main board are good.
After this, we measured that, when in the failure state, the main board always sends an "on" voltage to the power board for all the power pins to turn on, but never sends an "on" voltage to the backlight on pin. Toggling the power button does not change this state, though sometimes unplugging and replugging causes it to work properly again.
Right now our best guess is that there's some bad solder joint somewhere on the main board (though we've inspected all the boards by eye and don't see any noticeably bad components or solder joints). We're considering either purchasing a replacement main board and hoping that fixes it or first asking a friend of ours to try to reflow the main IC in case that's the issue.
Does anyone have any ideas what the issue is/how to narrow down the problem further (or even just how to confirm that the main board really is the issue so we can know to replace it)?