A90D

· Check the power connection.

· Check if the rear panel power switch is in the ON position.

· Try with another power cable.

· Try with another power outlet.

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· Press the B button on the remote to switch to volume curve 1.

· Turn up the volume of the source.

· Set the headphone gain to high gain by the GAIN button on remote.

· Turn up the volume of the downstream devices if you are using the Line out output of the unit.

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· The device did not power on. Check the power supply.

· Check that the proper input source is selected. Press the knob to switch input channel.

· Check the output setting. Doule-press the knob to switch output channel.

· Check the connections for all devices.

· Insert connection cables all the way in.

· Check the volume of all devices and whether they are muted.

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· Try with other songs.

· Try to switch to "LIFT" on rear panel.

· Check to see if the problem is with the source, downstream equipment and cables.

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· Check to see if the problem is with the source, downstream equipment and cables. You can try swapping the left and right channel connections.

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· Check to see if the problem is with the source, downstream equipment and cables. You can try swapping the left and right channel connections.

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· Enable remote control function in the setup menu first.

· Try to insert two fresh AAA batteries.

· Please aim at the remote control receiver.

· Bring the remote control close to the device.

· Use your Android phone's camera to look at the transmitter at the top of the remote, if it doesn't blink when you press the remote button, the remote is defective.

· If you have more than one Topping device, check that you are using the correct remote control.

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· Negative and positive voltage abnormal. Please update the firmware first.

· May be caused by high temperature. Turn the power off, wait for the unit to cool down sufficiently, and then turn the power on again. Please place the unit in a place having good ventilation.

· Probably overloaded. Try turning down the volume and then reboot the unit.

· Too low load impedance or short-circuit load. Check the connections with the speaker.

· Disconnect other devices and reboot. If the problem still persists, your unit may be defective. Please contact the store where you purchased it.

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· Amplifier circuit outputs abnormal DC voltage.

· Turn down the volume of this unit, turn it off and let it cool down for 1 minute before restarting it.

· Disconnect other devices, turn this unit off and cool it down for 1 minute and then restart it. If the problem still persists, your unit may be defective. Please contact the store where you purchased it.

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· Please re-flash the correct firmware.

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· Please re-flash the correct firmware. Reboot the computer or try with another computer.

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· Please re-flash the correct firmware.

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· Please re-flash the correct firmware.

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· Firmware upgrade failed. Please re-flash the firmware.

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