JBL Boombox speaker along with included charger and user documents.

JBL Boombox Won’t Turn On Unless Plugged In

When your JBL Boombox won’t turn on unless it is plugged in, this likely means one or more things.  Either your speaker is broken beyond repair, the battery inside no longer recharges due to age or heavy use, or, you accidently put your speaker into service mode a.k.a. secret or weird mode.  So, assuming that all the hardware and software in your speaker is still in working order, we’ll cover here the last possibility. Thus, we describe below how to get your JBL Boombox out of service mode, and restore proper operation to it.

JBL Boombox Service Mode Details

First, when in this (often called ‘weird’ or ‘secret’) mode, the JBL Boombox does not power ON unless you connect an external power source such as the included AC charger adapter. Thus, it will not run on the internal battery while in Service mode.  Furthermore, when you do apply outside power, it powers up without you pressing the Power button.  I.e. It comes on as soon as you apply power to the DC input port on the back of the speaker.

Further, you cannot turn off the Boombox while it is in Service mode, unless you disconnect the external power source. And then, it powers off without pressing the Power button.  So when this service mode is active, the Power button appears to not work.

Indeed, none of the buttons seem to work in Service mode, except for the ones needed to exit service mode.  E.g. The speaker won’t pair with any devices or other speakers when you press the Pairing button, and as mentioned, the Power button does not switch it off either.

How to Turn On Service Mode

This is what you may have done inadvertently at some point just prior to your speaker’s strange behavior starting… To turn on this Service mode, power up the speaker first, and then press the Connect+ and Volume UP buttons at the same time, until the speaker powers OFF, which usually takes ten seconds or so.

Find these buttons pointed out in the next picture. Note that you can enter this mode as long as the speaker is ON, and it doesn’t matter whether it’s connected to external power or not.  Also note that these buttons are very close to (beside) each other.  So it’s easy to press them both by mistake, especially with the Volume Up button is such a heavily used control.

Top view of the JBL Boombox speaker, showing the -Connect Plus- and -Volume Up- buttons.
JBL Boombox speaker, top view, showing the -Connect Plus- and -Volume Up- buttons.

JBL Boombox Won’t Turn On Unless Plugged In, How to Fix

Now you can restore proper speaker operation by disabling this mode. But note that when this Service mode is in effect, then to switch it back off, you must connect external power again. Why?  Because when in Service mode, the JBL Boombox won’t come on without outside power. But you can’t change modes without powering up the unit first.  Thus, you need the power adapter to make this fix.

  1. So, connect your speaker to AC power and turn on the speaker.
  2. Then, with the speaker Power button glowing, you press and hold the Connect+ and Volume UP button combo for ten seconds or so, until the unit powers off.
  3. Then, normal speaker operation returns.

Finally, at this point, the Power button should work again, whether or not you connect the AC adapter.

Related Posts to JBL Boombox Won’t Turn On Unless Plugged In, How to Fix

  1. JBL Xtreme Won’t Turn On Unless Plugged In

Other Posts About the JBL Boombox Bluetooth Speaker

  1. JBL Boombox Charging Instructions, Recharging Time
  2. Battery Indicator on the JBL Boombox Explained
  3. JBL Boombox Buttons Meanings, Functions, Codes
  4. How to Tell if JBL Boombox is Charging
  5. JBL Boombox Firmware Update Instructions


  1. JBL Boombox Splash Proof Power Bank Speaker Official Product Page at JBL.com

Revision History

  • 2021-07-29: First published.