Welcome back friends!
Today we have an RCA television that turns on correctly, but doesn’t want to show anything… YAAAY!
Television:40″ Class LCD 1080p Widescreen HDTV
Model #: 40LA45RQ
Symptoms: The tv powers up, with the indicator light going from red to blue. This means that everything should be on correctly, yet we cannot see anything on the panel.
- Before prying this apart, we have a hint that everything should be on and displaying right? So, we use that as an indicator that there is an image on the display, but we can’t see it. So, lets just grab a flashlight and shine it on the screen to see if there’s an image.
- With a flashlight, we can see the image on the screen! So, that must mean the backlights for the panel are not turning on.
- We take the back off and the usual: double check all the connections. Everything looked swell.
- So with the issue being with the backlights, we start off by checking the voltage from the power supply unit (PSU) to the backlight inverter connector, CN3 (White connector on the right) on the PSU. There was 24V there, so that’s all good and gravy.
- Next, we check for the backlight-on signal from the main unit, checking the pins at CN5 (Red connector on the right). There was around 3v, so that was good and gravy also.
- With the PSU testing okay, and the backlight-on signal being present, we suspect the problem lies with the backlight inverter itself (As shown). If not it could be the panel.
- We tested with our Fluke volt alert while we have some juice going to the TV. It didn’t pick up any readings from the backlight inverter while placed there.. so we’ve found the culprit.
- We went and replaced the backlight inverter and bam, checking for voltage, the backlight inverter shows power. After turning the display around, we can see the screens display without a flashlight. The tv lives!
Solution to Repair: Replace Backlight Inverter
Board Responsible: Backlight Inverter (Part #: SSI-400-14A01)
We went with trust that the indicators on the display were working properly. That helped a lot to pinpoint the problem within the backlight inverter.