When your JBL Boombox won’t turn on unless plugged in, this has several possible causes. Either it is defective, the battery inside no longer recharges, or you accidently put it the speaker service mode. So, assuming that everything in your speaker is still in working order, we cover here the last possibility. How to get your JBL Boombox out of service mode, and so, restore proper operation.
JBL Boombox Won’t Turn On Unless Plugged In: Service Mode Details
First, when in this (often called ‘weird’ or ‘secret’) mode, the JBL Boombox does not power ON without external power. 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.
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, and as 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 mode, power up the speaker first. Then press the Connect+ and Volume UP buttons at the same time. Hold them until the speaker powers OFF. This 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. It doesn’t matter whether external power is present or not. Also, these buttons are very close together. So it’s easy to press them both by mistake.
JBL Boombox Won’t Turn On Unless Plugged In: How to Fix
Now you can restore proper speaker operation by disabling this mode. But when Service mode is ON, 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.
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- So, connect your speaker to AC power and turn on the speaker.
- Then, with the speaker Power button glowing, press the Connect+ and Volume UP button combo. Then hold these in for ten seconds or so. Finally release them when the unit powers off.
- Then, normal speaker operation returns the next time you power up this speaker.
Finally, at this point, the Power button should work again, whether or not you connect the AC adapter.