Front view of the JBL Boombox BT speaker.

JBL Boombox Blinking Red Light, How to Fix

Many JBL speakers, including the Boombox, have a blinking red light when the battery is almost dead. We find this lamp in the battery gauge on the front lower center of the boombox grill. Sometimes though, this red LED flashes for long periods as you play the speaker.  So it begins pulsating during play and does not stop, even when you connect a charger.  Thus in this post, we offer reasons that this can happen.  Then we give possible fixes.

 JBL Boombox 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.

Picture of the red light glowing on the JBL Boombox battery gauge.
The red light glowing on the JBL Boombox battery gauge.

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

Picture of the battery gauge showing a full charge.
The battery gauge showing a full charge.

Or, once recharging finishes, all lights in this gauge go out.

Picture of the all-dark battery level gauge.
The all-dark battery level gauge.

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

Picture of the red light blinking on the JBL Boombox.
The red light blinking on the JBL Boombox.

1.The Power Outlet May Not Be Live

The Problem

The power adapter may not deliver any power because it is not getting any to begin with. This can happen due to a defective AC or car circuit or tripped circuit breaker. Furthermore, a blown fuse, faulty wiring, or general power outage might be to blame.

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 flip that switch ON.

2. Power Supply is Not Working Well

The Problem

The JBL Boombox red light continues blinking perhaps because your adapter provides SOME but not ENOUGH current. Its output energy can fall over time. So it might not deliver the correct amount if very old. Note that the boombox requires 4.0 amps 20 volts (80 watts) 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, get from JBL the exact replacement power supply for this boombox. Thys avoids possible damage to the speaker or the supply itself.

3. The Battery in the Boombox Speaker is Defective

The Problem

As lithium ion batteries age, they lose their ability to fully recharge. Plus, the characteristics of the current they draw changes as they get older. Normally, as a battery recharges, it draws less current as it charges. But in the case of cell failure, it may draw too much or too little amperage. Thus this can confuse the charging circuits. So they may behave like no charging is occurring even with voltage present.  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 1. 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 water on it.

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.

Picture of the top of the JBL Boombox with power OFF. Showing all buttons dark.
Top view of the JBL Boombox with power OFF. Showing all buttons dark.

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

The Problem

Even if you have the correct power supply, the current getting to the battery may be too low or high. This can happen when the battery management circuits fail.  Note that normally these systems read the battery status. Then they 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 online. The Boombox may also not play as long before going dead. Or it might not play at all, except when charging.

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, your best bet is to just buy another speaker. But be sure to recycle your old one though.

Other Posts About the JBL Boombox

    1. JBL Boombox Watts Output, Input, Battery, AC…
    2. How to Pair to iPhone
    3. Bluetooth Pairing Tips
    4. How to Fix the Not Charging Problem
    5. How to Turn On Bass Mode

References for JBL Boombox Blinking Red Light

    1. JBL Boombox Official Product Page
    2. Where to Buy the JBL Boombox