Factory Reset; Troubleshooting - Medeli MK401 Owner's Manual

Factory Reset

Hold down the [<] and [>] buttons at the same time, then turn on the
power. It will reset to factory default settings, and delete all user data
on the instrument, including user songs, user memory and user
sounds. The LCD will show "Loading!". When factory reset is
completed, the instrument will start normally.

Troubleshooting

Problem
The speakers produce a pop sound whenever
the power is turned on or off.
Speakers do not produce sound when the
keyboard is played.
The speakers produce noise when a mobile
phone is put near them.
The auto accompaniment does not play back
even when Sync is in standby and a key is
pressed.
Certain notes seem to be in the wrong pitch.
When connecting to computer, the instrument
cannot be recognized.
The pedal does not respond.
It cannot read/save to the SD card.
It shuts down after a period of time.
The Harmony function does not work.
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Possible Cause and Solution
This is normal and is no cause for alarm.
1. Check if the master volume is set too low.
2. Check if the R1/R2/L sound volume is set too low in the mixer menu.
3. Check if headphones are plugged into the PHONES jack.
Using a mobile phone in close proximity to the instrument may
produce interference. To prevent this, turn off the mobile phone or use
it farther away from the instrument.
You may be playing keys in the right hand range of the keyboard. To
start the accompaniment with Sync Start, make sure to play keys in the
left-hand range.
Make sure that the tune value is set to 0. Press and hold the [<] and [>]
buttons and turn on the power to restore factory settings.
Check if the USB cable is firmly connected. Try connecting another
USB port on the computer. This instrument is plug and play and should
work without installing a driver.
Check if the pedal cable is firmly connected.
Make sure your SD card is in FAT32 format and not multi-partitioned.
The auto power off function will turn off the instrument after a preset
period of time when the instrument is not in use. You can adjust the
auto-off function in the function menu.
Harmony function is not available when Sound R1 is a drum kit.