The pink Wonderboom 3. Showing the top and center front panels.
When the JBL Wonderboom 3 Won’t Turn ON, this likely means one or more things as follows.
JBL Wonderboom 3 Won’t Turn ON: Causes and Fixes
The battery may simply be dead. So try to recharge the unit with an AC power cord. But if that doesn’t fix this, then check out the next steps.
Your charger cord or adapter itself is faulty. So try swapping in a working charger and cord for the perhaps bad one. The JBL Wonderboom 3 may boot correctly once again.
Or, try to forcibly shut down the unit. Do this by pressing the Volume Up, Volume DOWN, and Pairing buttons, all at the same time. Hold a second or two, then release. This halts any running programs on the unit. Then press the Power button to start it again if the unit does not restart on its own.
The button contacts may have sand, dirt, or other debris in them. To repair this, you’ll have to take the JBL Wonderboom 3 apart since the innards of these buttons are not accessible from outside. Then blow, brush, or polish the switch contacts, and try to turn it ON again.
If it still doesn’t work, then the battery inside may be permanently dead. That is, it no longer recharges due to age, excessive charging, or heavy use. This would possibly be the case if the unit does power up when you connect the charger. So to resolve this, replace the battery. Again, this requires disassembling the Wonderboom, and of course, obtaining a new battery.
If you can get the unit to power ON with the charger, then try resetting the Wonderboom. The running programs inside could be in a corrupt state, which resetting often fixes. We describe how to do this below.
If the reset does not work, then try just letting the battery drain for several days. Disconnect the charger and set the unit aside. Then connect the charger and try to turn the speaker ON. It may work now.
Finally, if all the above checks fails, the unit is likely faulty. In this case, get a replacement unit.
JBL Wonderboom 3 Won’t Turn ON: Reset May Fix
This only works if you can power up this Wonderboom with the charger connected. So assuming that this is so, do the following.
1. Connect the Charger
As noted above, the unit may not work on batteries, but does boot when you connect it to AC power.
2. Be Sure That This Wonderboom is Not Paired with Anything Prior to Reset
The unit may not answer to the reset command while connected with a source Bluetooth device. So disconnect it before resetting. Since you can’t turn turn the unit OFF at this point then turn OFF Bluetooth on the device to which the 1 is paired. This will break the connection, which it is best to do prior to resetting.
3. Press the Power and the Volume DOWN Button Together for Five to Eight Seconds
Find the Power and Volume DOWN buttons. The Power button is on the top, near the front. Volume DOWN is the long plum line on the front, near the bottom. See these both pointed out by the green arrows in the next picture.
The -Volume DOWN- and -Power- buttons on the JBL Wonderboom 3.
The 3 then enters reset.
4. The Wonderboom Then Powers Down
Within a couple seconds, the unit switches off. Next, the falling electronic ker-plunk sound plays. Then the lamp in the Power button goes dark.
Top view of the JBL Wonderboom 3 BT speaker. showing the dark Power button.
5. Try Powering UP the JBL Wonderboom 3 Again
When powering up right after reset, the unit comes up in ready-to-connect mode, with the Pairing lamp rapidly flashing white. Assuming that the reset makes turning the unit ON work correctly again.