MVH-290BT/XEUC 75 6 7 85 6 7 8CDFABE5. DIAGNOSIS5.1 TROUBLESHOOTINGIN5PRE-GNDIN4IN2IN1Unable to turn on the powerCheck if the 10A blade fuse has not blown.If the fuse has blown, check the voltage.(Normal voltage)Voltage when the source is off: About 125mA [mA]Voltage at standby: About 2.5mA [mA]If the voltage is not normal, replace the product (otherwise MBL CMPX MODULE if it is available).If you do not find any error, replace the fuse.No sound from the speakersChange the source and check if you can hear sounds.If you can hear sounds in a particular source, replace the product (otherwise MBL CMPX MODULE if it is available).If you cannot hear sounds in any source, check the the signal in the input of PowerAMP IC (U4).IN1 U4 11-pin FLIN2 U4 12-pin RLIN3 U4 15-pin FRIN4 U4 14-pin RRIf you can find the signal, replace the PowerAMP IC.If you cannot find the signal, replace the product (otherwise MBL CMPX MODULE if it is available).(Check Point)No sound from the PreOUTCheck the impedance between the Ground of PreOUT and the Ground of this product.Check the power of MAIN BOARD PCB (Connector J9 15-pin: A5V).If the impedance is OPEN, replace the Poly Switch (FU1).If the impedance is SHORT, replace the product (otherwise MBL CMPX MODULE if it is available).Detach grill does not work.[New one]MVH-290BT/XEUC, MVH-291BT/XEUC, MVH-29BT/XEUW5,MVH-295BT/XEES[Conventional one]MVH-08UBG/XEUW5, MVH-08UB/XEUW5, MVH-85UB/XEES,MVH-88UB/XFBRNotes:Each of Detach grill Assy on conventional and new one can be used each other as they are electrically equivalent even if they are swapped.The difference is only the print of button, marked by red box in pictures below.When the detach grill is mounted on each unit, the function is followed by the unit on that.You can use this in case of troubleshooting if necessary.If the detach grill does not work normally, replace the the product (otherwise MBL CMPX MODULE if it is available).If the detach grill works normally, replace the detach grill (Detachable Assy).USB storage device is not recognized.Check the power of MAIN BOARD PCB (Connector J9 7-pin: K5V).If an error occurs in the power, replace the product (otherwise MBL CMPX MODULE if it is available).If you do not find anything error, replace the detach grill (Detachable Assy).* You may also check the power of the MAIN BOARD PCB by checking the LED power status in theconnected USB storage device.