JBL Boombox 2 Blinking Red Light, How to Fix

Front left view of the JBL Boombox 2 Bluetooth speaker.

Many JBL speakers, including the monstrous Boombox 2 model, have a blinking red light when the battery is almost out of power. In the case of this speaker, we find this lamp in the battery gauge on the front lower center of the speaker grill. Sometimes though, this red LED flashes for long periods as you play the speaker. E.g. It begins pulsating during play and does not stop, even when you connect a charger. Thus in this post, we offer reasons that this red light blinking happens on the Boombox 2. Then we give possible fixes for this common problem.

JBL Boombox 2 Red Light Blinking, Reasons and Fixes

It’s normal that the battery gauge displays a blinking red light when the juice left in it is very low. But this meter should turn white when you connect the speaker to a charger, and battery recharging begins.

The blinking red light on the JBL Boombox 2 speaker.

Normally though, this gauge only shows white lights. The number of lamps that glow tells you how full the battery is. It can appear as follows.

The battery gauge on the speaker showing 50 percent full, glowing white.

Or, if the speaker is OFF when charging starts, and you don’t turn it ON during charging, then once recharging finishes, all lights in this gauge go out. See this in the next picture.

The dark battery status gauge on the JBL Boombox 2 speaker.

But if the blinking red lamp in this meter does not change to white when you connect the charger, then several things might cause this. We list these below thus.

1.The Power Outlet May Not Be Live

The Problem

The AC or car adapter for the JBL Boombox 2 may not deliver any power because it is not receiving any to begin with. This can happen due to a defective AC or car circuit, tripped circuit breaker, blown fuse, faulty wiring, power failure, and the like.

The Fix

Check that your outlet has electricity by testing it by plugging in a lamp or other device. Reset circuit breakers if tripped, change the bad fuses, and if the outlet has a light switch that controls it, then be certain that that switch is in the ON position.

2. Power Supply is Not Working Well

The Problem

The JBL Boombox 2 red light continues blinking perhaps because the AC or car adapter you’re using provides SOME but not ENOUGH charging current, even though its getting the correct power input. Its output energy can fall over time. So it might not deliver the correct amount presently. Please note that this speaker requires 4.2 amps of charging current at 24 volts (100.8 watts) from the supply to fully recharge in the shortest time.

The Fix

The solution is to replace the adapter, preferably one that delivers at least these exact values. In this case, we suggest getting right from JBL the exact replacement power supply for this boombox, to avoid possible damage to the speaker or the supply itself.

3. The Battery in the Boombox 2 is Defective

The Problem

As lithium ion batteries age, they lose their ability to fully recharge, and the characteristics of the charging current they draw changes as they get older. Normally, as a battery recharges, it draws less and less current as it charges. But in the case of cell failure, it may draw too much or too little amperage, thus confusing the charging circuits into behaving like no charging is occurring. So, the red lamp keeps blinking.

The Fix

To fix this, replace the battery. But keep in mind that you can’t easily get to it in the Boombox 2. Indeed, changing the battery means that you must teardown the speaker.

But note that doing this likely breaks the water resistant seal. Thus the speaker will no longer be safe to use, if you get it wet.

Breaking this seal may also change the sound quality too. So get someone to replace the battery who knows how to pick the right replacement. They should also be able to restore the seal to as it was, as they reassemble the speaker. A good battery should fit well inside.

Front view of the BT speaker.

5. The Speaker Might be Defective when the JBL Boombox 2 Red Light Keeps Blinking

The Problem

Even if you have the correct power supply, with a working battery, the charging current that actually gets to the battery may be too low or too high. This can happen when the battery management circuits inside the Boombox 2 JBL speaker fail. Note that these systems read the battery status, and shut off the charging current when they deem the battery full.

But when they break, the battery might get no power at all. Thus, it never recharges. Again, in this case, the red light might never stop blinking, even with the charger attached. You may also see that the speaker doesn’t play as long before going dead. Or it might not play at all, except when you’re charging it.

The Fix

The best solution here, is simply to get a new speaker. Why? Because the circuits in this model are rather small. So unless you can replace the system board(s) yourself, or know someone who will do it for you, just buy another speaker to save a boat load of aggravation.