Good morning Badcaps -
I finally have some time to look at a TCL 55S405TBBA that's been sitting in the corner.
Symptoms: I turn on the TV, backlights turn on, the LCD glows, but i don't see anything on the screen. When i press the volume buttons or directional arrows on the remote, i hear the normal menu clicking sounds. The panel appears in this state probably 95-99% of the time.
When i leave the TV off for hours/days, then plug it in, i can get the video to display -- but it only works for several minutes. If I press power and turn it on again, i'm back to the same broken state.
What I've done:
Also, 1/8th of the screen is slightly a different shade of "black" when it initially powers on, but this evens out and the screen is uniform in look after a few seconds. Not sure if this is significant. I checked the panel caps in this region - no corrosion, no shorts. Please see the attached picture.
Sounds like a bad panel to me... but i'd like your opinion.
I finally have some time to look at a TCL 55S405TBBA that's been sitting in the corner.
Symptoms: I turn on the TV, backlights turn on, the LCD glows, but i don't see anything on the screen. When i press the volume buttons or directional arrows on the remote, i hear the normal menu clicking sounds. The panel appears in this state probably 95-99% of the time.
When i leave the TV off for hours/days, then plug it in, i can get the video to display -- but it only works for several minutes. If I press power and turn it on again, i'm back to the same broken state.
What I've done:
- Checked the supply voltages from the SMPS - looks nominal compared to the silkscreen voltages. I'll document them in this thread when i get back to it.
- I checked the fuse on the T-Con. It's good.
- Replaced the T-CON from known working and exact match from set with a broken screen. No change.
- Replaced the main board and LVDS cable - from the set with a broken screen. Also, no change in behavior.
- I disconnect one LVDS cable at a time - left only, and right only. No change. Cables were reseated as well.
- Measured the impedance of the caps on the panel side PCB (past the T-CON LVDS cables) - no shorts or low impedance paths found. Everything was several kOhm or higher.
Also, 1/8th of the screen is slightly a different shade of "black" when it initially powers on, but this evens out and the screen is uniform in look after a few seconds. Not sure if this is significant. I checked the panel caps in this region - no corrosion, no shorts. Please see the attached picture.
Sounds like a bad panel to me... but i'd like your opinion.
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