Help library: Help library: [LG TV] TV Keeps Turning Off When Connected to Set-Top Box

[LG TV] TV Keeps Turning Off When Connected to Set-Top Box

Troubleshooting Cinebeam Projectors 01/06/2026

<div class="content-service-view">
<p class="info-desc">
HDMI cables support CEC capability, enabling power control between products.<br>
The power may turn on or off automatically due to a malfunction of the CEC function.
</p>

<h2 class="tit">Causes and Symptoms</h2>

<li>The Auto Power function is on.</li>
</ul>

<h3 class="sub-tit">Does your TV turn on or off by itself?</h3>
<p class="info-desc idt">➔ Go to the Settings menu and disable the [Auto Power] feature.</p>

<h3 class="sub-tit">Going to [Auto Power] in the Settings menu</h3>
<p class="info-desc">➔ [2022 WebOS22]</p>       <p>
Press the <img style="vertical-align: bottom;" alt="setting" src="https://gscs.lge.com:/gscs/support/fileupload/downloadFile.do?fileId=MvI6tkgFojurmXHTqFLVw&amp;portalId=P1"> button on the TV remote and select [All Settings] → [General] → [External Devices] → [HDMI Settings] → [SimpLink (HDMI-CEC)] → [On] → [Off].
</p><p class="txt-idt">
1. Turn on the TV and press the [Settings] button on your TV remote.<br>
Select [All Settings] in the [Settings] menu.
</p>

<div class="img-only">
<img alt="entering All Settings by pressing Settings on the remote control" src="https://gscs.lge.com:/gscs/support/fileupload/downloadFile.do?fileId=yZsjX8xlFfYXZKUkfrWA&amp;portalId=P1">
</div>
<p class="txt-idt">2. Select [General] and then [External Devices].</p>

<div class="img-only">
<img alt="selecting External Devices from the general menu" src="https://gscs.lge.com:/gscs/support/fileupload/downloadFile.do?fileId=YSTMIXY0AcFJHO0jEsbIaw&amp;portalId=P1">
</div>
<p class="txt-idt">3. Select [HDMI Settings].</p>

<div class="img-only">
<img alt="selecting HDMI settings" src="https://gscs.lge.com:/gscs/support/fileupload/downloadFile.do?fileId=QzNZDSxFyPKZMjOxxHMpA&amp;portalId=P1">
</div>
<p class="txt-idt">4. Set [SimpLink (HDMI-CEC)] to Off.</p>       <p>※ In WebOS 6.0 or later, the Auto Power option is not available, and disabling SimpLink (HDMI-CEC) will make the controls from external devices invalid.</p>

<div class="img-only">
<img alt="Image to turn off simplink" src="https://gscs.lge.com:/gscs/support/fileupload/downloadFile.do?fileId=E8qxP83qlnZeEpGSXbiySQ&amp;portalId=P1">
</div>
<p class="info-desc">➔ [2020 WebOS5.0]</p>       <p>
Press the <img style="vertical-align: bottom;" alt="setting" src="https://gscs.lge.com:/gscs/support/fileupload/downloadFile.do?fileId=7jhLKrJiDxAjOyUFujNqQ&amp;portalId=P1"> button on the TV remote and select [All Settings] → [Connection] → [Device Connection Settings] → [SimpLink (HDMI-CEC)] → [On] → [Off].
</p>       <p>
※ Disable the TV power synchronization and automatic power standby mode on your set-top box.<br>
For detailed instructions, please contact your set-top service provider.
</p>

<div class="tip-box">
<strong class="tip-tit">Have you checked if the firmware version is up to date?</strong>

<div class="con-view">
If the problem persists after the actions are taken, contact LG Electronics service technician for diagnosis and precise check.
</div>
</div>

<div class="tip-box">
<strong class="tip-tit">How to set Auto Power in the Settings menu in different WebOS versions</strong>
<p>

<span><strong>[2021 WebOS6.0]</strong></span>

<span><strong>[2019 WebOS4.5]</strong></span>

<span><strong>[2018 WebOS4.0]</strong></span>

<span><strong>[2017 WebOS4.0]</strong></span>

<span style="color: rgb(0, 0, 0) !important;">
Press the <img style="vertical-align: bottom;" alt="setting" src="https://gscs.lge.com:/gscs/support/fileupload/downloadFile.do?fileId=RLi5E9OZSxMzDPddhKtGQ&amp;portalId=P1"> button on the TV remote and select [All Settings] → [General] → [SimpLink (HDMI-CEC)] → [Auto Power] → [On] → [Off].
</span>
</p><p style="color: rgb(0, 0, 0) !important;">
※ If your remote control does not have the [ <img style="vertical-align: bottom;" alt="setting" src="https://gscs.lge.com:/gscs/support/fileupload/downloadFile.do?fileId=QIfrNKJe40At4BKEljLrA&amp;portalId=P1"> ] button, press the Home [ <img style="vertical-align: bottom;" alt="home" src="https://gscs.lge.com:/gscs/support/fileupload/downloadFile.do?fileId=7K58bn6pigwfrV9XIjjoew&amp;portalId=P1"> ] button, and select Settings [ <img style="vertical-align: bottom;" alt="setting" src="https://gscs.lge.com:/gscs/support/fileupload/downloadFile.do?fileId=ZmM22LRdjct2lM4I7bew&amp;portalId=P1"> ] on the screen.
</p>

<div class="img-only">
<img alt="Image to select the setting icon on the TV screen" src="https://gscs.lge.com:/gscs/support/fileupload/downloadFile.do?fileId=56bRuJZr0ed8gugIJoWzA&amp;portalId=P1">
</div>
</div>
<p class="help-txt">This guide was created for all models, so the images or content may be different from your product.</p>    </div>

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[LG TV] TV Keeps Turning Off When Connected to Set-Top Box

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