LG S40TR: problems, parts and running costs

Checked: 2026-10-29

Summary

Owners most often report rear speakers that will not link and LG ThinQ app discovery problems, usually resolved by manual pairing or a return. Running costs are low: no required consumables and about 123.37 kWh a year, roughly $24.67 at $0.20 per kWh. It is a good buy at $199.99 or less, and strong value at $110 or below for a complete used set with all components.

Common problems and fixes

Rear speakers will not link — two owner reports from 2025; the manual pairing sequence (power off, press PAIRING until green blinks, power on, watch for solid green) and checking that the active rear is powered and the inter-rear cable is connected usually resolves it; if pairing fails on a fresh setup, use the warranty or return path. [9][10]
LG ThinQ app does not discover the bar — app discovery problems are not by themselves proof of dead hardware; check the app, firmware, Bluetooth permissions and manual pairing before assuming a hardware fault. [1][3][5][9]
No audio from the TV over HDMI — the cable must run from the TV’s ARC-labelled port to the bar’s HDMI TV (ARC) port, with HDMI-CEC/Simplink enabled and the TV digital audio output set correctly; optical is the fallback. [2][3][4]
No discrete sound from the rear pair on stereo sources — stereo PCM will not produce discrete rear ambience like a 5.1 track; use a true Dolby Digital or DTS multichannel source or an upmix mode, and confirm the rear units show a green link LED first. [1][3]
RF interference or dropouts — keep the units away from obstructions and interference, reconnect the subwoofer and rears, and read the status LEDs; no measured dropout incidence or confirmed systematic defect has been published. [3][10]
No dedicated center channel — dialogue comes from the two front drivers plus Clear Voice Plus processing, so a 5.1 system with a physical center localizes voices better. [2][6]
No Dolby Atmos, DTS:X or height effects — the decoder list is Dolby Digital and DTS Digital Surround only, despite Dolby trademark text on some listings and generic Atmos filters on some retailers. [2][4]
WOW Orchestra, WOW Interface and Sound Mode Share only on compatible LG TVs — other brands connect by ARC or optical without those features. [1][2]

Parts and consumables

Remote (AKB74935642) — $17.95 at LG Parts, observed; replace only if missing or broken; no scheduled replacement interval. [11][17]
AC/DC adapter (EAY65911503) — $53.95 at LG Parts, observed, with a future availability date of November 1, 2026; original rating is 23.0V at 1.31A; replace only if verified failed. [4][11][12]

Yearly running cost

There are no compulsory consumables; the only recurring items are two AAA batteries for the remote. Rated power is 22W for the bar, 35W for the subwoofer and 20W for the powered rear, 77W combined, with each component under 0.5W in standby. An illustration at 4 hours a day at 77W plus 20 hours at 1.5W works out to 123.37 kWh a year, or $24.67 at $0.20 per kWh; actual draw depends on volume, content and sleep behavior. Optional repairs if a part fails: remote at $17.95 or adapter at $53.95, which should not be annualized because failure rates are unknown. [2][11]

When it is a good buy

Price thresholds checked October 29, 2026: LG US direct at $199.99 sale against a $279.99 crossed-out price; BJ’s Wholesale Club at $199.99 against a $249.99 reference; Walmart restored at $149.99 with a 90-day warranty; the $149.95 Best Buy result is the SQC4R, not the S40TR. Editorial bands: $110 or below for a complete tested used set is strong value; $111 to $150 new or reliable refurbished is good if the accessory bundle and return policy are complete; $151 to $180 new is worthwhile for physical rears and ARC; above $230, compare more modern 5.1 or Atmos systems. Alternatives: Hisense HS5100 5.1 at $179.99 at Best Buy is better if a center channel matters; Samsung HW-B550F 2.1 at a $179.99 promotional price ($229.99 list) suits smaller rooms with fewer cables but has no rears; LG S60TR 5.1 at $399.99 buys a center channel and stays in the LG ecosystem. [1][7][8][13][14][15]