Flat-panel TV mounted on a living room wall with the screen off
4 components covered

Field manual · TV

OLED TVs (LG, Sony, Samsung QD-OLED): field service manual

Covers: LG OLED (WOLED) sets ~2016 onward, Sony BRAVIA OLED, Samsung QD-OLED (S90/S95 family). Menu names vary by year.

Cross-checkedBrands: LG, Sony, Samsung4 components

An OLED TV has no backlight: each pixel makes its own light. That removes the most common LCD repair (backlight strips) and leaves three field-serviceable blocks (power board, main board, T-con where separate) plus software and the panel-care routines. Burn-in, dead areas, lines in the panel and cracked panels are panel-only failures and usually make the set uneconomical to repair.

Safety first

  • Power-supply boards and backlight drivers hold dangerous voltage and can stay charged after the set is unplugged. Internal work is for trained technicians only: unplug, wait several minutes, and never touch the primary side of the power board, the large filter capacitor or the LED output connector with the set connected.
  • Never open the OLED panel module or press on the panel; handle it only by the frame and keep flex cables flat.
  • Never peel functional films (polarizer); only shipping films with a pull tab may be removed.
  • OLED panel replacement is a depot/manufacturer job; quote before committing.

How it works

Power path is like an LCD set: the power board keeps a standby rail alive, the main board commands power-on, and the power board brings up the main rails for the main board, the T-con and the panel's own drive supplies.

The main board handles inputs, processing and the smart platform (webOS, Google TV, Tizen), then sends video to the T-con, which drives the OLED panel through flex cables bonded to the glass.

Because each pixel emits light, there are no LED strips, no diffuser stack and no backlight driver. A black screen with sound is therefore never a backlight fault on OLED: think T-con, main board, power board or panel.

OLED pixels age with use, so the TV runs compensation routines. On LG, a short compensation runs after about 4 hours of cumulative viewing when the set is turned off with the remote, and a long Pixel Refresher/Pixel Cleaning runs about once every 2,000 hours. Sony and Samsung have similar automatic routines (Panel Refresh / Pixel Refresh). These need the set to stay plugged in and in standby.

Built-in retention protection includes pixel/screen shift, logo-brightness reduction and screen savers that start after a still image sits on screen.

Components & tests

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Official manufacturer documentation

Always confirm values against the tech sheet for the exact model.

OnCall Tech is a reference tool for trained technicians and can make mistakes. Always disconnect power and confirm with the manufacturer's documentation before you work. © 2026 OnCall Tech. Original content; not a reproduction of any manufacturer document.Generic part photos (not of this brand): Flat-panel TV mounted on a living room wall with the screen off by Daria Klet, Pexels License

Diagnostic guides for this appliance

Component test · TV

TV LED backlight strips and LED driver

LED strips are wired in series strings and run from a constant-current driver at high DC voltage (often around 80-200 V total). One dead LED opens the string and the driver shuts down. Test LEDs with a backlight tester, not a meter diode range, and replace all strips as a set.

6 steps ~120 minadvanced
Component test · TV

T-con (timing control) board: board or panel?

The T-con converts video from the main board into the signals that drive the panel rows and columns. Loose ribbons, a blown T-con fuse or a failed T-con cause image faults; lines that stay fixed in the same place usually mean the panel itself.

5 steps ~45 minadvanced
Component test · TV

TV power supply board

The power supply board makes a standby voltage that is always on, then switches on the main rails when the main board sends a power-on signal. Check standby, then the power-on signal, then main rails. The primary side holds a high-voltage charge.

5 steps ~45 minadvanced

Other tvs manuals

Manual · TV

LED/LCD TVs (all brands): field service manual

Flat-panel LCD TVs with LED backlight (edge-lit, direct-lit, mini-LED and QLED/QD-film sets), roughly 2010 to current. Board names and layouts vary by brand and series.

7 components7 common failuresSamsung, LG, Sony, TCL, Hisense, Vizio, Roku TV, All
Manual · TV

Smart TV software & connectivity (Roku TV, Google TV, Tizen, webOS, Vizio SmartCast): field manual

Smart platforms on US TVs: Roku TV (TCL, Hisense and others), Google TV / Android TV (TCL, Sony, Hisense), Samsung Tizen, LG webOS, Vizio SmartCast. Menu paths change between software versions.

3 components6 common failuresRoku TV, TCL, Hisense, Sony, Samsung, LG, Vizio
Manual · TV

TV wall-mount & installation basics: field manual

Flat-panel TVs with VESA mounting holes on drywall over wood studs, masonry walls, and basic cable/power concealment in US homes.

3 components3 common failuresAll
OLED TVs (LG, Sony, Samsung QD-OLED): field service manual · OnCall Tech