Exact model-family answer directory
LG CX OLED TV troubleshooting
LG CX OLED TV (OLED48/55/65/77CX*): what the CX is; an older webOS; four HDMI 2.1 ports at 40 Gbps; a dark picture; settings that darken; HDR and dark rooms, and a fix for each symptom below.
- What the CX isThe LG OLED CX is a 2020 OLED, a WOLED from before the evo panels, with the Alpha 9 Gen3 processor. It is self-emissive, with perfect blacks and no backlight. On a panel this age, faint uniform variations in near-black and normal brightness limiting are expected, not defects.
Confirm the model first
Which units this covers, and how to tell yours is one of them
- Model numbers and patterns
- OLED48/55/65/77CX*
Published specification
What is true of this model and changes how you fix it
- Panel2020 OLED (WOLED, pre-evo) with the Alpha 9 Gen3 processor — self-emissive, perfect blacks, no backlight. On a panel this age, faint uniform near-black variation and normal ABL dimming are expected, not defects.
- Smart platformThe older webOS (2020 platform) with the Magic Remote. This is the oldest LG TV in this library, and app support is the key issue: some streaming apps have dropped or no longer update on this webOS generation. Check the LG Content Store first; where an app is gone, an external streamer is the fix, not a TV repair.
- Gaming / HDMIFour HDMI 2.1 ports at 4K 120 Hz with VRR, ALLM and G-Sync — but at 40 Gbps, not the 48 Gbps of later models, so a few of the most demanding 4K 120 formats (e.g. 12-bit) are outside its bandwidth. That is a spec ceiling, not a fault.
- An older webOSIt runs the older webOS of 2020 with the Magic Remote. It is the oldest LG TV in the range, and app support is the main issue: some streaming apps have dropped or no longer update on this generation of webOS.
- Four HDMI 2.1 ports at 40 GbpsThe four HDMI 2.1 ports carry 4K 120 hertz with VRR, ALLM and G-Sync, but at 40 gigabits per second, not the 48 of later models. A few of the most demanding 4K 120 formats fall outside the bandwidth, which is a spec ceiling.
- A dark pictureA picture that seems too dark is usually a mode or an energy-saving setting, and on an OLED the Auto Brightness Limiter dims bright scenes.
- Settings that darkenEnergy Saving, the Automatic Brightness setting and the Eco mode all lower brightness. They can be turned off in the settings.
- HDR and dark roomsHDR content on an OLED is excellent in a dark room, but the TV's HDR brightness is lower than on a bright LCD in a bright room.
- Finding the modelThe label on the back and TV Information show the model, such as OLED55CXPUA.
Where these figures were read. lg.com/us/tvs/lg-oled55cxpua-oled-4k-tv (real model OLED55CXPUA, still live on LG US) (α9 Gen3, 4×HDMI 2.1 40Gbps 4K120, webOS 5.0)
Manufacturer support for this product line. LG Support — TV and home theater support. Official LG television manuals, webOS support, diagnostics and repair entry point.
Also read for this model. LG Support — LG TV support.
Exact questions
Questions that only have an answer for the LG CX OLED TV
My LG CX won't run a streaming app any more.+
The CX is a 2020 TV on an older webOS, and the most common cause is the app provider ending support for that webOS version. Check the LG Content Store for an update and cold-restart the TV. If the app has been withdrawn for this generation of webOS, it cannot be restored on the TV itself — an inexpensive external streaming stick brings it back, which is far cheaper than replacing a working panel.
Does the LG CX do 4K 120Hz for my PS5?+
Yes — the CX has four HDMI 2.1 ports with 4K 120 Hz, VRR and ALLM. They run at 40 Gbps rather than the 48 Gbps of newer LGs, so the very highest-bandwidth 4K 120 formats fall outside its range, but standard PS5 and Xbox Series X 4K 120 gaming works. Use a certified cable and turn on Game Optimizer.
My LG CX will not run a streaming app any more. Why?+
The app provider may have ended support for that webOS version.
Does it do 4K 120 Hz for a PS5?+
Yes, standard 4K 120 Hz works.
Why is the picture dark?+
A picture mode, energy saving or the brightness limiter.
Where is the model number?+
On the back and in TV Information.