TCL QM8 Mini-LED (QM850G / QM851G) and Q-Class Google TV: quick sheet

Covers: TCL QM8 Class mini-LED Google TVs (QM850G 2023, QM851G 2024; QM8K successor noted) and the related Q-Class Google TV line.

Single sourceBrands: TCL6 components

TCL's flagship mini-LED: very bright with high zone counts (about 1,080 zones measured on a 65-inch QM8; up to 2,300+ claimed on the 98-inch). Google TV only. Reports include early backlight failures and dimming/flicker behavior on some content that firmware may change.

Safety first

Unplug and wait before opening.
Live backlight/power tests are caution work.
Two-person lift.

How it works

Mini-LED backlight boards with a zone driver, Google TV main board, T-con and power board.

Two HDMI 2.1 ports carry 4K 120; RTINGS notes only one port does 4K 144 Hz and 1080p 240 Hz, so 'it won't do 144 Hz' is often the wrong port.

Store Mode on TCL Google TVs is exited through the TCL procedure (see the demo-mode guide).

Components & tests

Unlock all 6 components, specs, service mode and teardown

Full library + AI assistant for $34.90, one time.

Get lifetime access

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): LCD TV with the panel removed, showing the grid of lit LED backlights by RobertKuhlmann, CC BY-SA 3.0

Diagnostic guides for this appliance

Guide · TV

Soundbar won't turn on with the TV, or TV remote won't control its volume (HDMI-CEC)

One-remote control depends on HDMI-CEC over the ARC/eARC cable. Disabled CEC, the wrong HDMI port, an optical connection, a poor cable or a TV update that switched settings off cause nearly all of these calls.

7 steps ~30 mineasy

Guide · TV

Soundbar audio cuts out, pops or drops with movies/Atmos (ARC/eARC)

Dropouts usually come from an unstable ARC/eARC handshake or a format the chain doesn't handle well. Work through cable, firmware, CEC conflicts and the TV's digital audio format; optical is a stable fallback without Atmos.

8 steps ~40 mineasy

Guide · TV

Projector won't turn on or shuts off (reading the indicator lights)

Projectors protect themselves: overheating, lamp at end of life, and lamp-cover interlocks all stop the light source. Read the indicators against the model's table, then fix airflow, lamp seating or lamp life.

6 steps ~30 mineasy

Other tvs manuals

Manual · TV

Samsung QLED Q60 / Q70 / Q80 (2019-2024): quick sheet

Samsung non-Neo QLED (quantum-dot LCD) Q60, Q70 and Q80 series from about 2019 (R) through 2024 (D), Tizen OS. Not the Neo QLED QN85/QN90 mini-LED lines. The letter after the series number is the model year (e.g. Q80R, Q60T, Q80A, Q80C, Q80D as named in reviews).

7 components6 common failuresSamsung

Manual · TV

LG NanoCell (NANO75 etc.) and UHD UQ series (UQ7070 / UQ7570 / UQ8000): quick sheet

LG 4K LED-LCD sets on webOS: NanoCell NANO75/NANO80-class (2021-2023) and UHD UQ7070, UQ7570, UQ8000 (2022) and their UP/UR siblings. Not LG OLED (see the OLED quick sheet).

6 components5 common failuresLG

Manual · TV

Sony BRAVIA X90J / X90K / X90L full-array LED: quick sheet

Sony BRAVIA XR X90J (2021), X90K/X90CK (2022) and X90L/X90CL (2023) 4K full-array LED sets on Google TV.

6 components5 common failuresSony