LG CM4350 Mini Hi-Fi System - How to upgrade the software, Power supply troubleshooting – SMPS schematic

LG CM4350,  LG CMS4350F
Hidden key mode
Push both Front key and RCU key to activate it for 5 seconds.
Disc Lock On/Off (CD Function Only Active)
Front Key : STOP
RCU Key : STOP 

Check Version and Option code
Front Key : STOP
RCU Key : PLAY/PAUSE
You can change [Audio MCU Version <-> CD Controller Version <-> EEPROM Option] by SKIP+/-.
Clear EEPROM
Front Key : STOP
RCU Key : SKIP-
Edit EEPROM
Front Key : STOP
RCU Key : SKIP+
You can change the digit of option by SKIP+/-.
You can edit 0~f by REPEAT or PLAY/PAUSE key.
Bluetooth DUT
Front Key : STOP
RCU Key : PROGRAM
Bluetooth model only
Power Disc Lock On/Off (CD Function Only Active)
Front Key : STOP
RCU Key : EQ
Amp Clip On/Off
Front Key : STOP
RCU Key : Mute
Amp Clip Mode Change (Amp Clip On > Amp Clip Off > Level Down display)
Service information for EEPROM
> POWER ON 
> FLD no disc status or AUX status.
> Remote control ‘Fwd skip’ + Front ‘STOP’ push same time for about 5 seconds.
> FLD ‘OP-0….
> Move to appropriate position and make changes with remote control ‘skip, mode, play’ key.
> Press the ENTER key.
> FLD ‘write ok.
> Remote control ‘Fwd skip’ + Front ‘STOP’ push same time.
> FLD ‘E2P CLR
Completed.
SMPS Circuit diagram
No power - troubleshooting
If the unit doesn’t work by no power problem, repair the set according to the following
FUSE & BRIDGE DIODE
> Check and replace F901, BD901, TH901 or TH903 on SMPS board.
> Check if the fuse F901 is open or short-circuit.
> Check if the bridge diode BD901 is short-circuit by over current with a digital multi meter.
> Check if the NTC thermistor TH901 or TH903 is normal or open.
If the unit doesn’t work by no power problem, repair the set according to the following
> Check and replace D951 on SMPS board.
> Check the anode-cathod voltage of D951 with a digital multi-meter, it is normally 0.2 ~ 0.3 V.
> If it doesn’t have any voltage, it’s destroyed. Replace it with a new one.
Program download & update
MCS PROGRAM
Download program file name must be - HG520_FW_CM4750_DATE.bin
If security program (Water Wall) is activated on your PC, you must save the file to the USB storage device and disable the security software, then download the file to your set.
[When downloading the file, you should neither unplug the USB device, change to the other function, nor power off the device. USB device must be unplugged when the downloading process is completed.]
On VFD display screen
> No USB [insert USB device at USB function]
> Search
> Firmware
> Finish
Power off manually [when completed, remove USB device.]
Eq program
Download program file name must be
*CM4350: EQ_PRG_CM4350_***.BIN
*CM4450/CM4550: EQ_PRG_CM4550_***.BIN
*CM4650/CM4750: EQ_PRG_CM4750_***.BIN
If security program (Water Wall) is activated on your PC, you must save the file to the USB storage device and disable the security software, then download the file to your set.
Caution: When downloading the file, you should neither unplug the USB device, change to the other function, nor power off the device. USB device must be unplugged when the downloading process is completed.
On VFD display screen
> No USB [insert USB device at USB function.]
> Search
> Eq up
> Finish
Power off automatically [when completed, remove USB device]