JBL MBB2020 User manual

JBL MBB2020 Troubleshooting Guide
Prospec Electronics
Note: Please click on highlighted words for links to this page and our website.
1Wiring
2Compatible Accessories
3List of common issues
3.1. No power
3.2. Intermittent Power
3.3. Buttons/controls not responding/erratic controls
3.4. USB issues
3.5. Poor reception or no reception
3.6. No audio, speaker audio is unevenly distributed or some speakers not working
3.7. Low audio
3.8. Fluctuating Audio
3.9 Audio Shoots up when Bluetooth is on
3.10 Moisture in Display
3.11 Bluetooth Won’t Work
4 External Amplifier Issues/Subwoofer Operation
5 Reset Procedure

1.0. Wiring Follow the wiring diagram above.
•The red ACC wire is designed as the trigger to turn the radio on. It recommended that this wire is connected to an
on/off switch for purposes of lowering the current draw on the battery while the radio is not in use.
•Both red ACC and yellow battery wires must be connected to 12V+ for the radio to turn on.
•Ground (black) must be connected to a good 12V- source. Best source is directly to the battery.
•Speaker wires must be installed to the individual speaker’s terminals as labeled, positive and negative, respectively.
Do NOT combine any speaker wires as this will cause permanent damage to the radio’s output IC. Tape off any unused
speaker wires individually to prevent accidental shorting which can also harm the output IC.
•Antenna must be installed.
2.0 Compatible Accessories:See our website for the following add on accessories
SEAMINI2
SEAUSBMINI
JBL MC-20
MIL REM-50
MIL-RF9
Any antenna
Any amplifier
Note: can support: 1 two channel amplifier and subwoofer
1 four channel amplifier
3.0. List of common issues
3.1 No Power
•Check each button on the control pad for sticking. Under normal conditions, a faint click is heard upon pressing each
button. If any button does not click, initiate a warranty claim if you are under warranty.
•Ensure red and yellow leads are connected to a good 12V+ source. Both must have power for the radio to turn on.
•Ensure black ground wire is connected to a good reliable ground source.
•Open the fuse holder and check the fuse. Note, while in most situations, a bad fuse can be spotted visually, this may
not always be the case. The best method would be to use a multi-meter or a test light.
•Ensure the battery/power supply is putting out at least 12V while under load. The radio requires at least 11V to
operate normally.
•Check all connections for corrosion, looseness, or other condition that can produce a bad ground. Corrosion or
terminal looseness is the leading cause for most grounding issues and can cause excessive heat resulting in melting
wires or terminals.
•If possible, connect the radio power directly to a 12V system, bypassing any toggle switches. If radio works
connected directly to power, the problem might be with the toggle switch.
•If the above doesn’t help, initiate a warranty claim if you are within warranty.
3.2 Intermittent Power
3.2.1 Powers on and off constantly
Check voltage under load. At least 11V must be maintained consistently to operate the radio normally.
If voltage cannot be maintained, load test the battery or power supply.
Check all connections for corrosion, looseness, or other condition that can produce a bad ground.
3.2.2 Powers off and on while vehicle is moving
•Inspect all connections including the radio’s harness for looseness. Fasten down loose wires respectively.
Wiggle connections while the radio is operating to produce the symptom and narrow down the loose connection. If
radio cuts in and out while wiggling the wires on the radio side of the wire harness, initiate warranty claim.

3.3 Buttons/controls not responding/erratic controls
•Check each button on the control pad for sticking. Under normal conditions, a faint click is heard upon pressing each
button. If any button does not click, initiate a warranty claim if you are under warranty.
•Detach any additional equipment connected to the radio such as remotes, remote adaptors, and extensions. If the
stereo returns to normal operation, plug one attachment in at a time until the discovering the defective part.
•Reset the radio described in 5 Reset Procedure. Try radio again.
•Check all remote connections for water intrusion or corrosion including the MC20/REM50 themselves. This includes
any extensions connected to the radio or remote. If any connections are corroded, replace the corresponding part.
The best corrective measure to prevent this from happing again is to seal this connection with an adhesive shrink tube
and heat gun. If these materials are not readily available, make sure all connections are higher than the mounting
location of the remote and radio so any water entering these areas does not follow along the cable and into the
connection. Also make sure these connections are in dry areas.
3.4 USB issues
3.4.1 iPod/iPhone not charging or playing –these devises are not supported through the USB. To play iPod/iPhone,
use the headphone jack and connect to the AUX inputs of the JBLMBB-2020 or the Bluetooth setting.
Recommended additional purchases are the SEAMINI or SEAUSBMINI to clean up this connection and make it
easier to use.
3.4.2 MP3 player is not charging or playing –not all mp3 players will play via USB. The difference is in the
software of the mp3 player. Recommended additional purchases are the SEAMIN2 or SEAUSBMINI.
3.4.3 Flash Drive/ Thumb drive not playing
Only MP3 or Windows Media files are supported. These files can be recognized by viewing their file extension
on a computer; i.e., the file “My Favorite Song” will be followed by a “.” and the extension “mp3” or “wma”.
Some computer operating systems have extension view disabled. The feature can usually be enabled in the
computer’s folder properties.
ITunes music files will not play as these are not in mp3 format. Software converters can be purchased to
convert these files as others to mp3 format. Do not exceed a bit rate of 128 Kbps when converting.
Only drives formatted to FAT or FAT2 are supported. Most flash drives come this way standard.
Some flash drives com preloaded with proprietary software or other media organizational software that will
prevent the JBLMBB-2020 from reading the contents. Best practice is to completely format the drive to erase
all contents before loading music files.
Supported formats must not exceed a bit rate of 128 Kbps.
Check USB for corrosion
If your USB has more than 1000 songs on it, email us for software update. Models with PO number Al0155013
and AL0627721 need this software update.

3.5 Poor or no Reception
3.5.1 For an amplified antenna
Ensure the antenna is connected to power and ground according to manufacturer’s instructions
The antenna wire should never be coiled or wound up.
Check proximity of radio, speakers and antenna to gages, GPS equipment, depth finders, LED lighting or any
other source of Radio Frequency Interference (RFI) and Electronic Magnetic Interference (EMI).
3.5.2 For all other antennas
Inspect the antenna for torn wires.
The antenna wire should never be coiled or wound up.
Check proximity of radio, speakers and antenna to gages, GPS equipment, depth finders, LED lighting or any
other source of Radio Frequency Interference (RFI) and Electronic Magnetic Interference (EMI).
3.5.3 LED lighting causes low FM/AM audio or poor reception
•Never bundle the power source wires of the LED lighting to the power wires of the radio.
•If needed, the LED power wires and radio power wires should intersect at a 90 degree angle.
•The radio’s antenna must be as far away from the LED lights and power source as possible.
•The radio’s speakers also must be as far away from the LED lights as possible
•If all fails, upgrade the LED lights to a brand that is guaranteed not to emit RF or EMI.
3.6 No audio, speaker audio is unevenly distributed or some speakers not working
•Check Balance settings. To access and adjust these settings, press SEL button. Quickly press the SEL button again and
again until the desired setting is displayed. Use the volume buttons to adjust. Center the adjustment between
left/right.
•Check speaker connections. Ensure each speaker wire is routed to the appropriate speaker terminal for which it is
intended.
•Inspect all speaker wires for exposed wire and tape up as necessary. Make sure they cannot ground to one another or
make contact with any other potential power source or ground. NEVER combine speaker wires.
•If some speakers are working but others are not and the above methods do not help, swap the known working
speakers with the ones that are not working. This will help determine any defective speakers.
•If no audio and the above methods yield nothing, initiate a warranty claim if you are under warranty.
3.7 Low Audio
•Check speaker specifications –recommended impedance is 4ohm
•Check sound enhancements - To access and adjust these settings, press SEL button. Quickly press the SEL button again
and again until the desired setting is displayed. Use the volume buttons to adjust.
•Use the LOUD feature by pressing the LD button.
•LED lighting can cause low FM/AM audio –see section 3.5.3
3.8 Fluctuating audio or FM signal - Audio level constantly raises and lowers when the engine is started or revved. This
issue is more frequently caused by power fluctuations than radio failure.
•Check to ensure ground is good and no corrosion exists at connection points.
•Check all power wires for corrosion at connection points.
•Check for corrosion at battery terminals, bus terminals, and fuse panel.
•If in a boat or another motor vehicle, ensure the recommended plugs are being used the engine. Resistor plugs can
often block unwanted RF signal that can interfere with radio reception.
•LED lighting can cause fluctuating FM/AM audio –see section 3.5.3

3.9 Audio shoots up when Bluetooth is on
•Check the Bluetooth volume by holding down the SEL button until I-VOL appears. Then, press the SEL button until
BTVOL appears. This BTVOL is usually higher than the stock radio I-volume.
3.10 Moisture in Display
3.10.1 Water seen inside display after washing the mounting area
•Radio is not designed to withstand pressurized streams of water. When rinsing the radio or around the radio, a very
low pressure spray is recommended.
3.10.2 Slight fog after operation –normal in colder weather. Allow radio to run for 1-2 hours; this will burn off
moisture.
3.11 Bluetooth Won’t Work
3.11.1 Bluetooth Won’t Pair
Make sure your Bluetooth device is turned on and set to scan
Make sure the MBB2020 is on BT MUSIC. Hold down the MOD button until PAIRING appears
Turn all other Bluetooth devices off so the radio doesn’t get confused with what Bluetooth device to pair to.
Turn the pairing on the Bluetooth device first before pairing is turned on the radio.
Reboot your Bluetooth device.
Turn off the Wi-Fi on your Bluetooth device.
Reset your radio using the reset procedure in 5.
Try with another Bluetooth device.
Initiate warranty claim if nothing above works.
Note: Bluetooth will only work with Bluetooth streaming in but not out. This means that phones can stream Bluetooth
music in, but Bluetooth headphones that stream out will not work.
3.11.2 Bluetooth Code needed
Bluetooth code for the JBLMBB2020 is 1234.
3.11.3 Bluetooth is Paired, but the Volume is Low
•Make sure your volume on the Bluetooth device is on and turned up. If the volume is off on the Bluetooth device, then
audio will not play even if the radio and Bluetooth device are paired.

4External Amplifier Issues/Subwoofer Operation
4.2 Strong hiss –reduce the input gain on the amplifier until the hiss is reduced to an acceptable level while still
maintaining performance. Note, if both amplifier and stereo output can produce distortion, the input gain is
much higher than it needs to be. In most situations, reduced gain levels will not produce detectable
performance conditions.
4.3 Amplifier volume fluctuates or amplifier turns off and on
•Check the grounds to both amplifier as well as radio. Corrosion on any the contacts will reduce the ground.
•Check system voltage while operating radio and amplifier. If the voltage fluctuates and drops below 11.5 volts, load
test the battery, check the charging system, and check all power and ground wires and contacts for looseness or
corrosion.
•Ground the amplifier’s chassis to the stereo’s chassis.
4.4 Audio is extremely low - check the amplifier’s gain setting and increase if necessary.
Subwoofer Operation
Make sure the subwoofer is turned on by holding down the SEL button until I-VOL appears. Hit SEL until SUBW
appears. Turn SUBW to ON.
5 Reset Procedure
Method 1- Hold down the Power and Preset 1 button until the radio resets
Method 2- Disconnect the 12 pin connector plug from the power and ground for 15 seconds