LG CMS7520F/W - LG CM7520 – MINI HI-FI SYSTEM - FULL REPAIR TIPS GUIDE

NO POWER FUSE & DIODE BRIDGE
Check and replace the F901, BD901, TH901, and TH902 in SMPS board. How to Solve Problems (countermeasures) 1) Check the fuse F901 is open or short circuit. 2) Check if the diode bridge DB901 is shorted circuit over load with a digital multi meter. 3) Check if the NTC thermistor TH901 / TH902 is normal or open.

NO POWER D951 / D952, ZD951 Check and replace the D951, and D952, ZD951 in SMPS board. How to Solve Problems (countermeasures) 1) Check the voltage of the anode-cathode of D951 / D952 with a digital multimeter. The voltage is normally 0.2 ~ 0.3 V. If he does not have any tension it is because it has been damaged. Replace it with a new one. 2) Make sure the ZD951 is not short-circuited. If found shorted, replace it with another new.

DO NOT WHEN THE MACHINE IS ON BOOTS

The device does not work for problems related to the power failure when press the on both the front panel of the unit and the remote control button.

FLASH MEMORY (IC101)

Check and replace the IC101 on the motherboard.

How to Solve Problems (countermeasures)

1) Check 3.7VA in CN103 CN102, CN104 in standby mode. If there is 3.7 VA, check the SMPS board.

2) Check for 5.6 V, 12 VA FL, +, FL and 32 V to turn on the unit.

If the set does not work, regardless of changes in KEY1 to high or low as pressing the power button. The X100 and X101 to function normally, but if you cannot connect the device, please replace the IC101 for a new one on the motherboard.

The FVD NOT SHOW ANY PICTURE WHEN ON THE MACHINE

By connecting the device, icons or characters at the VFD are not displayed.

VFD

Check and replace the DIG301 on the front plate.

How to Solve Problems (countermeasures)

1) Make sure VKK (-32 V), FL + and FL- were out of SMPS for VFD through the main board.

2) Make sure 3.3 VA entered IC301.

3) Check that the IC101 output VFD_RST, VFD_CLK, VFD_STB and VFD_STB to the front plate.

4) Make sure the pin P1 ~ 15G of DIG301.

If there is no sign, replace IC301 a new one.

If there is no problem, replace with a new VFD.

NO START IN FUNCTION CD / USB

After connecting the power switch and see the message in the following order (HELLO -> VOL XX -> CD or USB) ON VFD, another message is not displayed in VFD, and not begin normally.

WITHOUT VCC33, VCC12

Check and replace IC505, IC509 in the MAIN board.

How to Solve Problems (countermeasures)

1) Check the voltage of IC505 pin2 in the MAIN board. If IC505 pin2 (about 4.9 V) and D501 input 5.6 VA fails, check VA 5.6 from the SMPS board.

2) If IC505 pin2 (about 4.9 V) is normal, check if PWR_CTRL (IC505 pin 1) is raised (about 3.3 V). If PWR_CTRL is not high, check the pin63 of IC101 & R149, R503.

3) If PWR_CTRL is high, check R592, R593 and if there is defective component, then replace IC505.

4) If 3.3 V (VCC33) is normal, check the output (pin2,4) of IC509 voltage. If 1.2 V IC509 pin2,4 is not released, then replace IC509.

NO START IN FUNCTION CD / USB

After connecting the power switch and see the message in the following order (HELLO -> VOL XX -> CD or USB) ON VFD, another message is not displayed in VFD, and not begin normally.

CRYSTAL (X501)

Check and replace X501 in the MAIN board.

How to Solve Problems (countermeasures)

1) If 3.3V & 1.2V is normal, select Reset 'Alto' the IC501 pino153 in the MAIN board. If PRINCIPAL_RESET is not high, check MICOM (IC101) pin59.

2) If PRINCIPAL_RESET is high, check the status of the 12 MHz crystal welding (X501).

3) If the crystal (X501) does not fluctuate, check R541, R542, C517, C518 around the crystal (X501). If there is defective component, then replace X501.

NO START IN FUNCTION CD / USB

After connecting the power switch and see the message in the following order (HELLO -> VOL XX -> CD or USB) ON VFD, another message is not displayed in VFD, and not begin normally.

FLASH SERIAL (IC503)

Check and replace IC503 in the MAIN board.

How to Solve Problems (countermeasures)

1) If the crystal (X501) is oscillating, check the serial flash (IC503) in the MAIN board. Check pin8 (VCC), pino6 (CLK), pin 1 (CS #), pin2 (DO), pin5 (DI) waveform below.

2) If the pins1, 2, 5, 6, 8 do not give results, check the damping resistor (R511, R513, R514, R515) of IC503. If the IC503 damping resistor is OK, then replace IC503. (It must download the program)

3) After changing IC503, if not already under the waveform, check IC501 (DSP IC).

NO SOUND

If there is no sound output on the USB function, repair the machine according to the instructions below.

THE USB FUNCTION

Solution

Check and replace the IC501, IC504 in the main and IC3U01 card into the USB adapter.

How to Solve Problems (countermeasures)

1) Check for +5 VU to USB card. Check for 5.6 V Pin1, 2 in CN3U1.

2) Check USB D ± the main board to the USB board.

A. Check USB_HUB_DN / DP signals IC501 (Pin16, 18)

B. Check signal USB1 / 2_DN / DP IC504 of CN502 (Pin1, 2, 4 and 5). If there are any problems, check the power for each IC. The power is normal but, if the waveform signal to the IC is distorted or no signal exists, replace it with a new one.

3) Make sure the "AMP block of digital audio" in Item 6-3 is normal.

NO SOUND

If there is no sound output in the function DIGITAL AUDIO AMP DAMAGE, repair Apparatus according to the following instructions.

DAMAGE TO AMP DIGITAL AUDIO (IN ALL FUNCTIONS)

Check and replace the IC701, IC702, IC703 in the MAIN board.

How to Solve Problems (countermeasures)

1) Check the ± FL, FR ± signs ± RL, RR ±, ± SW1, SW2 & ± the IC602 for IC701, 702 and 703 in each input function. If there is no signal, check that the I2S audio signals were received at the IC602.

2) Check PVDD_50V. If 50 V is abnormal, check the SMPS.

3) Check 12 for the operation of the IC AMP door.

A. All voltages are normal, but +12 V is low, there is the possibility of being damaged AMP IC.

B. Remove a ferrite bead between FB703, FB707 and FB713 one by one.

By removing the output choke if +12 V is recovered, it means the IC attached to it is damaged.

Replace the IC with a new one.

4) Check the impedance between SPK + and GND and SPK - and GND.

A. If the impedance is 0 Ω, the IC may have been damaged.

B. After removing the heat sink, replace it with a new one.

If an IC AMP among the three is damaged, "AMP_PDN" to R103 changes from HIGH to LOW at regular intervals.

The sound is not transmitted by turning off the AMP function.

NO SOUND

If there is no sound output on the AUX function, repair the machine according to the instructions below.

AUX IN FUNCTION

Solution

Check and replace the IC202 on the motherboard.

How to Solve Problems (countermeasures)

1) Check the signs AUX_L/R IC202 (pin7, 8).

2) Make sure ADC_BCK, ADC_LRCK & DAC_MCLK were inserted the IC501 to the IC202.

3) Make sure ADC_DATA was inserted into the IC202 to the IC501. If there is no signal, check for +5 V and +3.3 V (ADC) on IC202. If NG, replace it with a new one.

4) Check the signal flow after the I2S of IC501 to IC602. If there are any problems, check the power for each IC. Food is normal, but if the signal waveform to the IC is distorted or there is no sign, replace it with a new one.

5) Make sure that the AMP block digital audio is good. If AMP is damaged, replace it with a new one.

NO SOUND

If there is no sound output on the PORT function. IN, repair the machine according to the instructions below.

IN FUNCTION PORT IN

Solution

Check and replace the IC202 on the motherboard.

How to Solve Problems (countermeasures)

1) Check the PT_L / R signal from the main board to the USB board.

2) Check that comes PT_LR pin 1 and 3 of CN3M01 to Pin 1 and 3 CN202.

3) Check the signs POT_L / R for IC202 (Pin21, 22).

4) Make sure ADC_BCK, ADC_LRCK & DAC_MCLK are inserted from IC501 to the IC202.

5) Make sure ADC_DATA is entered from the IC202 to the IC501. If there is no signal, check for +5 V and +3.3 V (ADC) on IC202. If NG, replace it with a new one.

6) Check the I2S signal flow for ic602 IC501. If there are any problems, check the power for each IC. Foot is normal, but if the signal waveform to the IC is distorted or there is no sign, replace it with a new one.

7) Make sure that the AMP block digital audio is good. See tab "AMP AUDIO DIGITAL". If AMP is damaged, replace it with a new.

NO SOUND

If there is no sound output in TUNER function, repair the machine according to the instructions below.

IN FUNCTION TUNER

Solution

Check and replace IC202, TU101 on the motherboard.

How to Solve Problems (countermeasures)

1) Make sure TUNER_LR was inserted pin 1 and 3 of TU101 to IC202 (Pin23, 24). If there is no signal, check for 3.3 V in Tuner voltage. Make sure the Tuner control signals (CLK, DAT, CE, RST, GPO2) were inserted into the IC101 for TU101.

If not, replace the TUNER with a new one.

2) Make sure ADC_BCK, ADC_LRCK & DAC_MCLK were entered from IC501 to the IC202.

3) Make sure ADC_DATA was inserted from IC202 to the IC501. If there is no signal, check for +5 V and +3.3 V (ADC) to the IC202. If Not Good, replace it with a new one.

4) Check the audio signal flow I2S the ic602 for IC501. If there are any problems, check the power for each IC. Foot is normal, but if the signal waveform to the IC is distorted or there is no sign, replace it with a new one.

5) Make sure that the AMP block digital audio is good. See tab "AMP AUDIO DIGITAL". If AMP is damaged, replace it with a new one.

NO SOUND

If there is no sound output in the MIC IN function, repair the machine according to the instructions below.

FUNCTION IN THE MIC

Solution

Please check and replace the IC603, IC605 on the motherboard.

How to Solve Problems (countermeasures)

1) Check the MIC_SIG signal to pin 6 of the CN601. If there is no signal, check the signal to pin 6 CN3M01 the MIC board. Make sure the signal enters pin to 6 CN3M01 HOME card.

2) Make sure MIC_SIG is inserted from CN601 Pin 6 Pin 3 for IC605 (MIC AMP).

3) Check that the amplified signal is input from Pin4 IC605. If there is no signal output, check for +12 V for IC605, IC605. Replace with a new one if it has a problem.

4) Make sure MIC_BCK & MIC_LRCK is inserted from IC507 and IC603 for DAC_MLCK from IC501 for IC603. Make sure MIC_DATA is made from IC603 pin 9 to pin 7 of the IC602. If there is no signal, check for +5 V and +3.3 V on IC603. If it is abnormal, replace it with a new one.

5) Check the I2S signal flow of IC603 for IC602. If there are any problems, check the power for each IC. If the signs are abnormal, replace them with new ones.

6) Make sure that the AMP block digital audio is good. If AMP is damaged, replace it with a new one.

EXPLODED VIEWS

HIDDEN 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

2. 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+/-.

3. Clear EEPROM

„ Front Key : STOP

„ RCU Key : SKIP-

4. 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.

5. Bluetooth DUT

„ Front Key : STOP

„ RCU Key : PROGRAM

„ Bluetooth model only

6. Power Disc Lock On/Off (CD Function Only Active)

„ Front Key : STOP

„ RCU Key : EQ

7. Amp Clip On/Off

„ Front Key : STOP

„ RCU Key : Mute

Amp Clip Mode Change (Amp Clip On => Amp Clip Off => Level Down display)

TO MAKE PROGRAM DOWNLOAD

The name of the program file to download should be CM7520_YYMMDDX.HEX

If the security program (Water Wall) is enabled on your PC, you must save the file in a storage device USB and disable the security program for the next download the file to your device.

Caution: When downloading the file, you must neither disconnect the USB device, move to a and other function or turn off the power. The USB device should only be disconnected when the total download process finished.

2. CD DOWNLOAD THE GUIDE

The name of the program file to download should be HE003_DATE_00.BIN

If the security program (Water Wall) is enabled on your PC, you must save the file in a storage device USB and disable the security program and then make download the file to your device.

3. GUIDE DOWNLOAD QE

The name of the program file to download should be EQ_PRG.BIN

If the security program (Water Wall) is enabled on your PC, you must save the file in a storage device USB and disable the security program and then make download the file to your device.

AMPLIFIER

Stereo mode 310 W + 310 W (4 Ω at 1 kHz)

Front Surround Mode 310 W + 310 W (4 Ω to 1 kHz, THD 10%)

Subwoofer 310 W (4 Ω at 1 kHz ,, THD 10%)

NO START IN FUNCTION CD/USB
After connecting the power switch and see the message in the following order (HELLO => VOL XX => CD or USB) ON VFD, another message is not displayed in VFD, and not begin normally.
SDRAM (IC502)
Solution
Check and replace IC502 in the MAIN board.
How to Solve Problems (countermeasures)
1) Check the waveform below and status of SDRAM welding (IC502) in the MAIN board. If pin17 (CAS), pin18 (RAS), pin19 ( CS), pino38 (CLK), pino29 (address), pin2 (DQ) not give results, check the damping resistor (R508, R506, R504, R507).
2) If the resistor is OK, then replace IC502 (SDRAM).
3) After changing IC502, if not already under the waveform, check IC501 (DSP IC).

NO START IN FUNCTION CD/USB

After connecting the power switch and see the message in the following order (HELLO => VOL XX => CD or USB) ON VFD, another message is not displayed in VFD, and not begin normally.

DSP IC (IC501: MLC3700)

Check and replace IC501 in the MAIN board.

How to Solve Problems (countermeasures)

1) After checking them on the previous pages on NOT Startup if the unit is not booting, check the soldering status IC501. Check the startup option (R598, R594, R597) of IC501 (DSP IC).

2) If the shape of boot wave below fails, then replace IC501 (DSP IC).

The MD DOES NOT WORK

When the sound does not come out of the CD function, you cannot hear the music and read the data a CD drive if servo motors do not work in MD. This step serves to check the engine AXIS among other things.

SHAFT MOTOR

Solution: Check and replace the IC407, IC408 on the motherboard.

How to Solve Problems (countermeasures)

1) Check the signal the IC407 Pin16. If there is no signal, check for 3.3V (RF) and X402.

2) Check the SP-SP + and the IC408 from the motor shaft driver CN405. It is about 3.6 Vp-p. If there is no signal, check for 1.8 V and 5 V on IC408.

3) Make sure the FFC cable is properly connected to the CN405 and the MD.

4) Check the MD. If the spindle motor is shorted or has a problem, you cannot run the CD disks.

Check the function after changing the other MD.

MD NOT WORK

When the sound does not come out of the CD function, you cannot hear the music and read the data a CD drive if servo motors do not work in MD. This step It serves to check the SLED MOTOR among other things.

SLED MOTOR

Solution: Check and replace the IC407, IC408 on the motherboard.

How to Solve Problems (countermeasures)

1) Check the signal SLDO the IC407 Pin15. If there is no signal, check 3.3V (RF) and X402.

2) Check the SLED + & SLED- the IC408 CN405 to the motor shaft of the driver. It is about 2.9 Vp-p. If there is no signal, check 1.8 V and 5 V on IC408.

3) Make sure the FFC cable is properly connected to the CN405 and the MD.

4) Check the MD. If the engine is short or has some kind of problem; it will not be able to move the module the pick-up. Please check the function after switching to another MD.

The MD DOES NOT WORK

When the sound does not come out of the CD function, you cannot hear the music and read the data a CD drive if servo motors do not work in MD. This step serves to The check OPENING AND CLOSING MOTOR TRAY among other things.

OPENING ENGINE AND TRAY CLOSE

Solution: Check and replace the IC407, IC408 on the motherboard.

How to Solve Problems (countermeasures)

1) Check the MOT_OPEN & MOT_CLOSE signs of Pin104 and 105 of the IC501 IC408. If there is no signal, check 1.8V and + 5V of IC408.

2) Make LOAD ± of IC406 for CN405 for the operation of opening / closing of the engine tray. Should be approx 3.85 Vp-p. If there is no signal, check for +5 V on IC406. If you have any problems, replace it with a new one.

3) Make sure the FFC cable is properly connected to CN405 and MD.

4) Check the MD. If the engine tray are short or have any problems, you cannot open or close the tray.

Check the function after changing another MD.

The MD DOES NOT WORK

When the sound does not come out of the CD function, you cannot hear the music and read the data a CD drive if the pickup module in the MD not function. This step serves to check the LASER TRACK Activator.

ACTIVATOR OF LASER TRACK.

Solution: Check and replace the IC407, IC408 on the motherboard.

How to Solve Problems (countermeasures)

The tracking actuator causes the laser beam is positioned at the center of a track on the CD.

1) Check the signal TRD pin14 of IC407. If there is no signal, check for 3.3 V (RF) and X402.

2) Check T - & T + the CN404 IC408 for the operation of the tracking actuator. If there is no signal, check for 1.8 V and 5 V on IC408.

3) Make sure the FFC cable is properly connected to the CN404 and the MD.

4) Check the MD. If the pickup module has a problem, you cannot move the laser beam on the left or the right.

Check the function after changing another MD.

MUTE

Not out there on the CD sound function, repair the machine according to instructions as follows.

IN FUNCTION CD

Solution: Check and replace the IC801 IC501, IC602, the MAIN board.

How to Solve Problems (countermeasures)

1) Check the signs CD_BCK, CD_LRCK & CD_DATA IC407 to the IC501. If there is no signal, check that the RF signals and MD servant were received at the IC407.

See "The failure of the MD" section.

2) Check the I2S signal flow. <Audio signal interface I2S>

- DAC_BCK: IC501_pin4 -> IC507_pin14, 16 -> R821 of IC801 (Beat option) & IC602_pin4

- DAC_LRCK: IC501_pin5 -> IC507_pin5, 7 -> R820 of IC801 (Beat option) & IC602_pin5 (44.1 kHz)

- DAC_DATA: IC501_pin6 -> R817 near the IC801 (Beat option) -> IC602_pin6, 9

- DAC_MCLK: IC501_pin3 -> R818 near the IC801

If there are any problems, check the power for each IC. If power is normal, but if the waveform signal to the IC is distorted or there is no signal, replace it with a new one.

Make sure the "AMP block of digital audio" is normal.

NO SOUND

If there is no sound output on the USB function, repair the machine according to the instructions below.

THE USB FUNCTION

Solution: Check and replace the IC501, IC504 in the main and IC3U01 card into the USB adapter.

How to Solve Problems (countermeasures)

1) Check for +5 VU to USB card. If 5.6 VA to pin2 of IC3U01 (LDO) does not come out, check pin21 ~ 23 CN103. If VA 5.6 is normal and 5 VU IC3U01 pin3 does not come out, then replace IC3U01.

2) Check USB D ± the main board to the USB board.

Check USB_HUB_DN / DP signals IC501 (Pin16, 17)

Check signal USB1 / 2_DN / DP IC504 of CN602 (Pin1, 2, 4 and 5) If there are any problems, check the power for each IC. Power is normal, but if the waveform signal to the IC is distorted or no signal exists, replace it with a new one.

3) Make sure the "AMP block of digital audio" is normal.

Master Electronics Repair !

Thursday 7 February 2019

LG CMS7520F/W - LG CM7520 – MINI HI-FI SYSTEM - FULL REPAIR TIPS GUIDE

LG CMS7520F/W - LG CM7520 – MINI HI-FI SYSTEM - FULL REPAIR TIPS GUIDE