UE40D7000L Samsung LED TV Software upgrade, factory mode, alignments, service mode, AllShare, Disassembly and more

Samsung LED TV - UE40D7000L*, UE46D7000L*, UE55D7000L* Software upgrade, factory mode, alignments, service mode, AllShare

Alignments and Adjustments

General Alignment instruction
1. Usually, a color LED-TV needs only slight touch-up adjustment upon installation.
Check the basic characteristics such as height, horizontal and vertical sync.
2. Use the specifed test equipment or its equivalent.
3. Correct impedance matching is essential.
4. Avoid overload. Excessive signal from a sweep generator might overload the front-end of the TV. When inserting signal markers, do not allow the marker generator to distort test result.
5. Connect the TV only to an AC power source with voltage and frequency as specifed on the backcover nameplate.
6. Do not attempt to connect or disconnect any wire while the TV is turned on. Make sure that the power cord is disconnected before replacing any parts.
7. To protect against shock hazard, use an isolation transformer.

Entering Factory Mode
To enter ‘Service Mode’ Press the remote -control keys in this sequence :
● If you do not have Factory remote – control

Power Off > Info > Menu > Mute > Power On.

If you  have factory remote control

Info > Factory

Troubleshooting

Check the various cable connections frst.
• Check to see if there is a burnt or damaged cable.
• Check to see if there is a disconnected or loose cable connection.
• Check to see if the cables are connected according to the connection diagram.
2. Check the power input to the Main Board.
3. How to distinguish if the problem is caused by Main board or T-Con.
a. No Video : If the problem is No Video but BLU is on and Indication LED is blinking repeatedly and faster than nomal booting, replace the T-Con board.
b. Distorted Picture : Check the inner patterns.

How to check inner pattern
1. Factory mode (Mute > 1 > 8 > 2 > Power on when TV is in ‘Stand-by mode’)
2. Move to SVC menu.
3. Move to Test Pattern.
4. Check inner patterns.
(This model only support FBE, READ PRE, READ POST)

White Balance

Perform Calibration in the Lattice Pattern before adjusting the White Balance

Color Calibration
Adjust spec.
1. Source : HDMI
2. Setting Mode : 1280 x 720@60Hz
3. Pattern : Pattern #24 (Chess Pattern)

4. Use Equipment : CA210 & Master MSPG925 Generator

Method of Color Calibration (AV)
1) Apply the NTSC Lattice (N0. 3) pattern signal to the AV IN 1 port
2) Press the Source key to switch to "AV1" mode
3) Enter Service mode
4) Select the "ADC/WB" and "ADB" menu
5) Select the "AV Calibration" menu.
6) In "AV Calibration Off" status, press the ">" key to perform Calibration.
7) When Calibration is complete, it returns to the high-level menu.
8) You can see the change of the "AV Calibration" status from Failure to Success.

Method of Color Calibration (Component)
1) Apply the 720p Lattice (N0. 6) pattern signal to the Component IN 1 port
2) Press the Source key to switch to "component" mode
3) Enter Service mode
4) Select the "ADC/WB" and "ADB" menu
5) Select the "Comp Calibration" menu.
6) In "Comp Calibration Off" status, press the ">" key to perform Calibration.
7) When Calibration is complete, it returns to the high-level menu.
8) You can see the change of the "Comp Calibration" status from Failure to Success.

Method of Color Calibration (PC)
1) Apply the VESA XGA Lattice (N0. 21) pattern signal to the PC IN port
2) Press the Source key to switch to "PC" mode
3) Enter Service mode
4) Select the "ADC/WB" and "ADB" menu
5) Select the "PC Calibration" menu.
6) In "PC Calibration Off" status, press the ">" key to perform Calibration.
7) When Calibration is complete, it returns to the high-level menu.
8) You can see the change of the "PC Calibration" status from Failure to Success.

Method of Color Calibration (HDMI)
1) Apply the 720p Lattice (N0. 6) pattern signal to the HDMI1/DVI IN port
2) Press the Source key to switch to "HDMI1" mode
3) Enter Service mode
4) Select the "ADC/WB" and "ADB" menu
5) Select the "HDMI Calibration" menu.
6) In "HDMI Calibration Off" status, press the ">" key to perform Calibration.
7) When Calibration is complete, it returns to the high-level menu.
8) You can see the change of the "HDMI Calibration" status from Failure to Success.

Connector voltages and descriptions

Software Upgrade
Software Upgrade can be performed by network connection or downloading the latest firmware from “www.samsung.com” to a USB memory device.

By USB
Insert a USB drive containing the frmware upgrade fle, downloaded from “www.samsung.com” into the TV.
be careful not to disconnect the power or remove the USB drive until upgrades are complete. The TV will be turned off and on automatically after completing the firmware upgrade. When software is upgraded, video and audio settings you have made will return to their default settings.
[write down your settings so that you can easily reset them after the upgrade]

By Online
Upgrades the software using the Internet.
* First, confgure your network. For detailed procedures on using the Network Setting, refer to the ‘Setting the Network’instructions.
* If The internet connection doesn’t operate properly, connection can be broken, please retry downloading.
If the problem still happens, download by USB and upgrade.

Stanby mode upgrade(Off/On)
A manual upgrade will be automatically performed at selected time. Since the power of the unit is turned on internally, the screen may be turned on slightly for the LED product. This phenomenon may continue for more than 1 hour until the software upgrade is complete.

Disassembly

AllShare

AllShare™ connects your TV and compatible Samsung mobile phones/ devices through a network. On your TV, you can view call arrivals and SMS messages, and received by your mobile phones. In addition, you can play media contents including videos, photos, and music saved on your mobile phones or the other devices (such as your PC) by controlling them on the TV via the network. Additionally, you can use your TV for browsing web pages on your mobile phones.
N For more information, visit “www.samsung.com” or contact the Samsung call center. Mobile devices may need additional software installation. For details, refer to each device’s user’s guide.

Setting Up AllShare
 MENU → Network → AllShare Settings → ENTER
AllShare Settings
Media (On / Off) : Enables or disables the media function. When the media function is on, you can control Media contents play using mobile phones or other devices that support DLNA DMC.
Message (On / Off) : Enables or disables the message function. (for call arrivals, and SMS messages received by your mobile phones)

Media / Message
Shows a list of mobile phones or connected devices which have been set up to use the Media or Message function with this TV.
The Media function is available in all devices which support DLNA DMC.
• Allowed / Denied : Allows/Blocks the devices.
• Delete : Deletes the devices from the list.
This function only deletes the name of the device from the list. If the deleted device is turned on or tries to connect to the TV, it may appear on the list again.

Using the Message Function
You can view call arrivals and SMS messages received by your mobile mobile phone, through the alarm window, while watching TV.
NOTE
• To disable the alarm window, set Message to Off in the AllShare Settings.
• Whether OK is selected or not selected after a message has appeared once, the message will be deleted from the alarm window.
• When a message from an unknown mobile phone is displayed, select the mobile phone in the Message menu in AllShare Settings, and then select Denied to block the phone.
Message View
If a new SMS message arrives while you are watching TV, the alarm window appears. If you select OK, the contents of the message are displayed.
You can confgure the viewing settings for SMS messages on your mobile phones. For the procedures, refer to the mobile phone manual.
Some types of characters may be displayed as blank or broken characters.
Call Arrival Alarm
If a call arrives while you are watching TV, the alarm window appears.
Schedule Alarm
You can view scheduled events in the alarm window while you are watching TV.
You can confgure viewing settings for scheduled contents on your mobile phones. For the procedures, refer to the mobile phone manual.
Some special characters may be displayed as blank or broken characters.

Using the Media Function
An alarm window appears informing you that media contents (videos, photos, music) sent from a mobile phone will be displayed on your TV. The contents are played automatically 3 seconds after the alarm window appears. If you press the RETURN or EXIT button when the alarm window appears, the media contents are not played.
NOTE
• The first time a device accesses your TV through the media function, a warning popup window appears.
Press the ENTER button to select Allow. This permits the phone to access the TV freely and use the Media function to play content.
• To turn off media contents transmissions from a mobile phone, set Media to Off in the AllShare Settings.
• Contents may not play on your TV depending on their resolution and format.
• The ENTER and “◄/►”  buttons may not work depending on the type of media content.
• Using the mobile device, you can control the media play. For details, refer to each mobile’s user’s guide.

Electro help - Service Modes, Circuit Diagrams, Firmware Update procedure, Disassemble procedure, Universal remote control set-up codes, Troubleshooting and more....

GV411-2 Grundig Videoplus – drive mechanism repair procedure, how to eject the tape manually, mechanism adjustments and more

VCR G-type drive mechanism adjustments, disassembly and assembly, position of gear wheels and levers, how to eject manually and more...

Drive Mechanism

The tape deck is fitted with three motors providing:

– Precision drive for the headwheel
– Direct drive for the capstan and the reels
– Drive for the cassette compartment and tape threading/unthreading operations.
Special features are:
– Quick start
– Short winding time
– Automatic cleaning of video heads with a cleaning roller.
To obtain a high repair standard developed a range of service kits (A, B, C …). These kits cover all important spare parts which engage with each other.
The position numbers (Pos. …) in this description are also specified in the exploded views.
Test Equipment / Jigs

Test cassette Test cassette (HiFi) Nylon gloves

9.27540-1011 9.27540-1016 commonly available

Due to the fact that most of the components are secured with snap hooks only the important parts will be described in the following. The only parts fastened with screws:

– cassette compartment
– scanner
– capstan motor
– A/C (combi) head

When changing the position of the cassette compartment (lift) during repairs, the compartment must be moved manually to the "Eject" position on completion of the repairs

Lowering the Cassette Compartment by Hand (without cass.)
– Disconnect the video recorder from the mains.
– Release the locks R  and S of the cassette compartment and move it inwards until the cassette compartment lowers by a small amount.
– Turn the threading motor counterclockwise (Fig. 3) until the cassette compartment is down.

Click on the pictures to zoom in

Manual Ejection of the Cassette
If the tape deck does not unthread and eject the cassette by pressing the Eject button this function can also be effected manually by turning the driving gear at the threading motor. To avoid slackening of the tape, turn the capstan motor (counterclockwise)  and the driving gear alternately until the tape is completely wound up in the cassette.

Position of Gearwheels and Levers
(deck position "unthreaded, cassette compartment down")
The following diagrams show in detail the marked components and their correctly aligned position on the top and bottom side.

Removal and Reassembly of the Cassette Compartment
Removal:
– Disconnect the video recorder from the mains.
– Release the locks R and S  of the cassette compartment and move it inwards until the cassette compartment lowers by a small amount.
– Turn the driving gear of the threading motor in the "threading" direction  until the gearwheel (Pos. 103L) disengages.
– Release the bracket (Pos. 102L) from the shaft of gearwheel "A"

– Unscrew the 4 screws A  on the underside of the cassette compartment.

– Remove the front panel and raise the cassette compartment to remove it.
Preparations for Refitting the Cassette Compartment:
The cassette compartment and the tape deck must be fitted in a definite position. If the positions of the gearwheels and levers they take after removal have been changed while servicing certain preparations are required before refitting the cassette compartment and the tape deck.

Gearwheel Positions for Refitting the Cassette Compartment:
– Cassette compartment down, gearwheel "A" engaged.
Note: For video recorders which are fitted with cassette lift gear wheels (A and B) marked with arrows, the arrows must show towards each other.
– Cassette loading gearwheel (Pos. 103L) is released (if it is not the drive gear of the threading motor must be turned to release it).
– Put on the cassette compartment.
– Fasten the cassette compartment with the 4 screws A at the bottom.
– Place the bracket (Pos. 102L) onto the shaft of gearwheel "A" and lock it in.

Bottom of Drive Mechanism
Capstan belt (Pos. 126), pulley (Pos. 128G) and sensor print assembly removed.

Headwheel

Do not touch the headwheel with bare hands. Wear the nylon gloves.
Removal:
– Undo 2 screws X, remove the bracket (Pos. 22M) and the head amplifier.
– Insert the reference pin "C" (delivered with each service headwheel) into the hole of the scanner motor and turn the headwheel until the pin locks into the hole of the rotor..
– Set the extractor to the position "3 upper plate" (upper clamping element).
– Insert the extractor into the headwheel.
– Turn the lever by 90° in the direction of the arrow "OPEN" and remove the upper clamping element..
– Turn the lever by 90° in the direction of the arrow "CLOSE" and tighten the upper clamping element.
– Change the extractor to the position "0 lower plate" (lower clamping element).
– Insert the extractor into the headwheel.).
– Turn the lever by 90° in the direction of the arrow "OPEN" and remove the headwheel together with the lower clamping element.

Installation:
– Before fitting the new headwheel, make sure that the motor spindle is clean and undamaged (the spindle should be free of grease and must not be touched with bare hands).
– Put the 3 pins of the extractor into the new headwheel (with protective cap) so that they are inserted into the lower clamping element (the extractor is set to the position "0 lower plate")
– Turn the lever by 90° in the direction of the arrow "OPEN".
– Position the headwheel so that pin "D" of the protecting cap engages with the hole of the stator. Press the headwheel down in the middle with a force of 1N and turn the lever of the extractor counter clockwise in the direction of the arrow "CLOSE".
Attention: The upper protecting cap and the 2 Mylar films (0.15mm thick) remain on the headwheel during this process.
– Change the position of the extractor to "3 upper plate" (upper clamping element).
– Place the clamping element onto the pins of the extractor and turn the lever by 90° in the direction of the arrow "OPEN".
– Position the extractor with the clamping element on the headwheel and turn the lever in the direction of the arrow "CLOSE".
– Remove the protecting cap from the headwheel and withdraw the 2 Mylar films laterally from the air gap.
– Remove the reference pin "C" from the bottom side of the Drive Mechanism.

Mechanism exploded view

Adjustment of the Azimuth Angle and Height of the Head
– Connect an oscilloscope to the Audio output.
– Play the section of the test cassette with the 400Hz standard audio signal.
– Adjust for maximum output voltage with the height adjustment screw .
– Play the section of the test cassette with the 8kHz standard audio signal.
– Adjust to maximum output voltage with the azimuth adjustment screw..
– If necessary, repeat this process.
– Check the tilt angle.
If the tape transport was completely out of adjustment or if several components in the tape path have been replaced, it is possible that the have to be repeated several times.

Adjustment of the Horizontal Distance (x-distance)
– Call up the service test programme: Press the "STOP" button on the remote control and then the "play" button on the video recorder and hold them down for at least 5s. Autotracking is switched off.
– Before this adjustment, take out and reload the test cassette (start from Eject position).
– Play back the black/white part of the test cassette.
– With the eccentric screw adjust the "TRIV" signal to maximum voltage (DC-coupling).
– To cancel the service test program: Mains reset or press the "Standby" button.

Brake Band Adjustment
– Lower the cassette compartment. Turn the pulley of the threading motor  in the "threading" direction until the cam wheel takes the position shown in Fig. 29.
– Adjust the brake band (Fig. 27, Pos. 14P) by means of the tape tension adjusting tool (from the underside of the tape deck, Fig. 26) so that the edge of the elbow of the tape tension arm (Pos. 15) overlaps with the left inner edge of the left guide.

Tape Tension Adjustment
– Play a cassette (E 180) starting from the beginning of the tape.
– Measure the tape tension between the full-track erase head (Fig. 22, Pos. 16) and the reverse roller (Fig. 22, Pos. 23) by means of the tentelometer (for this press the full-track erase head to the left).
– Adjust the spring (Fig. 27, pos.11) to a tape tension of 0.24N ±0.02N (24g ±2g) by means of the tape tension adjustment tool.

 Checking the Friction Clutch

– Lower the cassette compartment. Turn the pulley of the threading motor (Fig. 3) in the "threading" direction until the cam wheel takes the position shown in Fig. 29.
– Place the torque meter on the right reel (Fig. 28).
– Turn the capstan motor to move the right reel clockwise.
– Keep turning until the reading on the torque meter does not change any more (Fig. 28).
– The torquemeter must read 10.5 mNm ±25% (105gf-cm ±25%).

Checking the Reverse Brake
– Lower the cassette compartment. Turn the pulley of the threading motor in the "threading" direction until the cam wheel takes the position shown in Fig. 30.
– Turn the lever (Fig. 31, Pos. 19J) to the left so that the swivelling gear (Pos. 17J) does not engage with the right gearwheel (Pos. 18J).
– Place the torque meter on the right reel and turn the latter counterclockwise until the reel just starts to slip (Fig. 28).
– The torquemeter must read 7mNm ±3mNm (70gf-cm ±30gf-cm).

Pressure Roller (Pos. 37)
– Set the tape deck to the "Eject" position.
– Unhook and remove the pressure roller spring..
– Release the pressure roller guide (pos. 41N) from the guide in the threading motor holder (Pos. 40) and turn the pressure roller guide assembly clockwise until the pressure roller and the guide (41N) can be released and removed..
Attention: Take care that the capstan does not come into contact with grease. Reassemble in reverse order.

Threading Roller Unit, Right
– Set the tape deck to the "Eject" position.
– Compress the two snap hooks by means of tweezers and remove the reverse roller from the holding plate.
– Release the loading arm from the holding plate and push the latter towards the front of the deck to remove it from the guide.
After replacing the threading roller unit (right), check and if necessary readjust the tape transport.

Threading Roller Unit, Left
– Set the tape deck to the "Eject" position.
– Unhook the tension arm spring (pos. 11) to avoid the tension arm spring being pre-loaded.
– At the bottom side of the tape deck, partially unhinge the sensor print and remove the tension lever (pos.112N).
– Compress the two snap hooks by means of tweezers and remove the reverse roller "A" from the plate "B" .
– Release the loading arm (left) from the holding plate and withdraw the latter through the cutout in the chassis.
– Reassemble in reverse order.
After replacing the threading roller unit (left) check and if necessary readjust the tape transport.

See the previous post to know more.

Grundig GV-411 Video recorder, service adjustments, service mode function details, Power board schematic

VHS-System
1/2” video cassette recorder
Tape speed ............2.339cm/s (Standard play)
Head to tape speed ...4.84m/s (Standard play)
Winding time of forward wind/rewind of a E180 Cassette: ... typically 260s

Service Test Program

Calling up, Checking the Levels of and Terminating the Service Test Program
The service test program can be called from any tape drive function other than the data entry functions (station search, …). 

While it is operating in the service mode, the VCR remains fully operational in all tape drive functions.
• Calling up the Service Test Program
Press the "STOP" button on the remote control and the "play" button on the video recorder in that order and hold them down for at least 5 seconds. 

The display will then show the values of Level 1.
• Checking the Levels of the Service Test Program
The service test program (Service Mode) is subdivided into 4 levels:
Level 1 – Keyboard control IC version, mask no. of the sequence control computer and the keyboard control computer
Level 2 – Tape deck sensors
Level 3 – Error status and error code
Level 4 – Operating hours meter.
The levels can be changed step by step by pressing the "SELECT" button on the remote control handset. Level 4 is again followed by Level 1.
• Terminating the Service Test Program:
Press the "STANDBY" button or disconnect the video recorder from the mains.

Level 1 of the Service Test Program
Mask and Version Numbers of the IC
The display is optically subdivided into three blocks of figures and characters, that is from left to right, the keyboard control IC version, the mask numbers of the sequence control computer and the keyboard control computer.

Level 2 of the Service Test Program
Checking the Tape Deck Positions and the Deck Sensors (without a cassette loaded)
The tape deck sensors can be checked by a four-place indication. The two digital places on the left for the tape drive state indicate the position of the cassette compartment and the threading roller units.
The two digital places on the right indicate several sensors. The indicated value changes with each operation of a sensor.

Tape Deck Position and Function of the Init Switch
The  function of the Init switch dependent on the tape deck position. For this, the number of the threading tacho pulses (FTA) is important. These signals are generated by the threading tacho generator (butterfly sensor) which is mechanically connected with the threading motor.

Level 3 of the Service Test Program
Error Codes and Error Status
The last error code and error status that occurred is stored in the Timer RAM and is saved even if the VCR is disconnected from the mains. To erase the data, press the "CLEAR" button on the remote control while in the service mode.

Monitoring the Tape Deck Functions
For monitoring the tape deck functions the tape deck is fitted with sensors which supply the following tacho signals according to the functions:
– WTR – reel right
– FTA – threading tacho
– FG – capstan motor
– PG/FG – headwheel motor
When one tacho pulse is missing during the operation of the tape deck, the VCR tries to move the cassette compartment to the "EJECT" position.

Level 4 of the Service Test Program
Operating Hours Meter
The operating hours meter indicates the number of hours the headwheel has been rotating.

Erasing the RAM and EEPROM
Press the buttons >> and << simultaneously on the recorder and connect the mains plug.
This erases and initializes the EEPROM. The customised station memory and the internal processor RAM are erased (with the exception of tape deck parameters and options).
Attention: If the EEPROM has been cleared or replaced the video recorder must be realigned..
On replacement of the EEPROM the option code must be entered additionally.

VCR Option Code
The VCR option codes "A"..."E" serve the purpose of activating the respective software stored in the mask-programmed IC of the different versions of video recorders. The option code is stored in the EEPROM.
– Call up the service test programme: Press the "STOP" button on the remote control handset and "play" on the video recorder in that order and hold them down for approx 5s at least. (The display will then show the values of service test programme – level 1.)
– Call up the option code "A": Press the "STOP" button on the remote control handset and "play" on the video recorder in that order and hold them down for 5s at least.

The display will then show the request to enter the option code.

– Enter the option code as specified in the table "VCR Code Numbers".
– Enter option code "A", see VCR Code Numbers (e.g. "005"), on the remote control handset.
Attention: All functions of the respective VCR will only be available if the option code has been entered correctly.
– Confirm the entered code with the "store" button on the VCR.
To verify the correct entry, the display will show the option code "A" as a hexadecimal number for about 2s,

Subsequently, the VCR switches automatically to the next option code to be entered.
– The option codes "B"..."E" are entered analogously to code "A".
Having entered the option "E", the VCR terminates the option code programme and switches over to the service test programme - level 1.
– Checking the option code:
– Call up the option code "A" .
– The code number can be checked by pressing the "store" button on the VCR without previously entering the code number.

Click on the pictures to magnify

Modulator "ON/OFF"
Switching the modulator on and off
– Call up the language selection option by pressing the buttons "eject" and "play" on the local keyboard simultaneously.
– Then press the "play" button, the display shows "TEST PICTURE ".
– Press the "Tracking" button, the message "MODULE ON " or "MODULE OFF " appears on the display.
– To switch over between the two operating modes press and hold the "Tracking" button for at least 5 seconds. The new mode will then be indicated on the display.

– Terminate the function by pressing button "STANDBY".

Power Supply (NSM)
The power supply unit is designed for two IC-versions: One version has the power transistor integrated in the driving IC (SPH4690 - IC7007), the other version (TDA4605 - IC7005) has not; the transistor is an external component (T7035) in this case.
The following description is confined to the version with the external power transistor.
In this free-running blocking-oscillator type mains stage, the IC7005 carries out the drive and monitoring of the MOS power transistor T7035 and also all necessary control and monitoring functions. The IC7005 receives on pin 1 information from the optocoupler OK7080 (mains isolation!) concerning the amplitude of the 5.4V supply on the secondary side. The current supply for the IC7005 takes place on pin 6 via the resistors R3054 and R3056 until the switch-on level is reached.
After start up the supply voltage is obtained via the diode D6027 from the winding 1, 9 of the transformer.
The series circuit consisting of the power transistor T7035 and the primary winding 6, 7 of the blocking oscillator transformer is connected to the rectified mains voltage (C2070). During the conducting phase of the transistor, energy is stored in the transformer which is fed to the secondary windings in the cut-off phase. The IC7005 controls the transferred energy by the switch-on period of T7035 so that the secondary voltages are held constant largely independent of mains voltage and load variations. The required control information is produced via the optocoupler. In addition, zero transition detection is carried out on IC7005-(8) by the information from winding 1, 9 via R3027.

Overvoltage and Overload Protection
If an overvoltage condition occurs, the supply voltage monitoring circuit responds via IC7005-(6) and interrupts the drive to the MOS transistor T7035. If the overvoltage condition is still present after restart, the complete process is repeated ("sensing process").
With short circuit secondary voltages, the IC7005, in combination with the drain current simulation (pin 2), takes up a repeated scanning state and limits the power.
Mains Undervoltage
In IC7005 a protection circuit for mains undervoltage conditions operates via pin 3. The threshold value is determined by R3005 and R3007.

Reset
When connecting the video recorder to the mains, the IC7411 generates the switch-on reset pulse with the reset capacitor C2414 on pin 4.
The resulting "POR" (Power On Reset) on IC7411-(17) is applied once as a HIGH pulse (approx. 30ms) via T7405 to the sequence control computer IC7410-(46) "IPOR". On another path, this pulse is also fed via the phase-shifting delay circuit T7030 / T7031 on the keyboard control board to the control computer IC7101-(12) as a negated pulse.

NICAM Decoder (ONIC)
General Information on NICAM
The NICAM (NEAR INSTANTANEOUS COMPANDED AUDIO MULTIPLEX) Transmission System is a digital stereo sound transmission technique.
This technique is a standard for sound transmission in television engineering. Compared to the conventional analog methods, this technology makes it possible to achieve an appreciable improvement in the signal-to-noise ratio and the dynamic range.
In a way similar to the analog stereo/ two-channel sound technology applied in Germany for example, also with NICAM, a digital sound/data signal with a separate carrier is additionally added to the conventional vision and sound signal. Apart from two digital sound channels of 10Bit each this digital signal contains scaling, identification as well as coding data for stereo, mono, two-channel sound or the data transmission.
The total dynamic input range is divided into eight stages. The socalled "Scaling Factor" identifies the respective stage and serves as the multiplication factor for the 10Bit data word. Hence its name. The scaling factor is determined every 2ms at a sampling rate of 32kHz and, together with the operational sign-bit, results in a dynamic total of 14Bit. With this method, the data rate is reduced to 704kBit/s compared to 896kBit/s of a real 14Bit transmission. 

To conceal this loss of information, use is made of statistical characteristics of the sound signal and the properties of the human ear.
Apart from this compressed data transmission, a further advantage of the Nicam-System is its low sensitivity to interference due to the use of 4PSK-Modulation (Phase Shift Keying = Phase Keying). This improvement in quality requires, however, an even more sophisticated design of the transmitter as well as of the receiver. 
NICAM Signal Processing
The "SSIF" sound-IF-signal is fed through solder contact 1970-(14) to IC7700-(29). In IC7700, the signal passes through a bandpass, a gain controlled amplifier and a mixing stage with QPSK demodulator. The phase detector corrects the differences between the "Carrier-VCO" and NICAM-IF frequency. The integrated "DATA SLICER" generates the digital signals from the NICAM-IF signal. In the "BIT RATE CLOCK RECOVERY" stage the original data clock is produced. This stage is followed by the NICAM decoder, the controller and the de-emphasis stage (digital filter J17). Subsequently, the processed signals are taken to the D/A-converters (DAC R and DAC L). The analog signals (left - IC7000-(15) / right - IC7000-(8)) are each subjected to an amplifier stage (T7701 / T7702) where they are filtered and adjusted in level. Via the plug contacts 1970-(2/4) the signals are taken to the IF amplifier for further processing.
The evaluation of the NICAM status (2 mono channels – two-channel sound, 1 mono channel / 1 data channel, stereo and NICAM-sound = analog sound) is carried out in the controller interface of IC7000.

Keyboard Control Unit (ODCE1)
The microcomputer IC7101 is the heart of the keyboard control unit and takes over the following functions with the corresponding function groups:
– Evaluation of the keyboard matrix.
– Decoding of the remote control commands from the infra-red receiver IC7103.
– Quartz clock
– Integrated RAM for storing the timer data.
– Driving the display.
– Bidirectional serial interface (DATD1 - pin 20 / 21, CLKD1 - pin 19) for data communication between the keyboard control computer and the sequence control computer
– I2C-bus interface (SDA - pin 79, SCL - pin 23) to the chassis board: EEPROM (IC7412), Tuner (1701), input selection switch (IC7552), audio circuit stage (IC7100) and NICAM Decoder (IC7700).
– The drifting of the tuner or the aerial signal generates the AFC control voltage in the frontend circuit on the chassis board. This voltage is supplied to pin 78 and the keyboard control computer readjusts the tuner tuning voltage via the I2C bus.
– In the case of power failure (max. 7 hours) the 220mF capacitor C2997 at pin 33 supplies the clock and the RAM. The diode D6099 prevents C2997 from discharging. During this period a LOW level exists at pin 2 so that further functions of the IC are switched off by the system quartz Q1001 at pin 13 / 14.

Service work after changing the Family Board:
– 2.1 Sequence Control / Deck Electronic (DE) .... Adjustment no. 1
– 2.4 Audio (AF) ............................................ Adjustment no. 1.1, 2

Family Board – Sequence Control / Deck Electronic (DE)
Test aids: Test cassette
Service work after changing the …
… Family Board or Headwheel: Adjustment no. 1
… IC7412: Adjustment no. 1
2.2 Frontend (FE): Adjustment no. 3, 4
2.3 Audio (AF): Adjustment no. 2
Service Test Program: Entering the VCR Option Code (para 1.5.2)

Family Board – Frontend (FV)
Test equipment: Oscilloscope with 10:1 Test Probe, Voltmeter, Colour Generator
Service work after replacing…
… the Tuner: Adjustment no. 2
… the IC7201: Remove R3743 – the demodulator changes automatically to a default value.

Family Board – Video/Chroma (VS)
Test equipment: Oscilloscope with 10:1 Test Probe, Frequency Counter, Colour Generator
Service work after replacing the Family Board:

Family Board – Audio (AF) & Keyboard control unit
Test equipment / aids: AF Millivoltmeter, AF Generator, branded Video Cassette.
Service work after replacing the Family Board, the RP Head or the Erase Head: Adjustment no. 1.1, 2

Keyboard Control Unit (ODCE1)
Test equipment: Frequency Counter
Service work after replacing the Keyboard Control Unit:

LG CM4650 Mini Hi-Fi System SMPS and power amplifier schematic, repair procedure, hidden key modes and more

MODELS: LGCM4650, (LGCM4650, LGCMS4750F)

1) The pick-up incorporates a strong magnet, and so should never be brought close to magnetic materials.
2) The pick-up should always be handled correctly and carefully, taking care to avoid external pressure and impact. If it is subjected to strong pressure or impact, the result may be an operational malfunction and/or damage to the printed-circuit board.
3) Each and every pick-up is already individually adjusted to a high degree of precision, and for that reason the adjustment point and installation screws should absolutely never be touched.
4) Laser beams may damage the eyes.  Absolutely never permit laser beams to enter the eyes. NEVER switch ON the power to the laser output part (lens, etc.) of the pick-up if it is damaged.

If there is dust on the lens surface, the dust should be cleaned away by using an air bush (such as used for camera lens). The lens is held by a delicate spring. When cleaning the lens surface, therefore, a cotton swab should be used, taking care not to distort lens.

Never attempt to disassemble the pick-up.
Spring has excess pressure. If the lens is extremely dirty, apply isopropyl alcohol to the cotton swab.
(Do not use any other liquid cleaners, because they will damage the lens.) Take care not to use too much of this alcohol on the swab, and do not allow the alcohol to get inside the pick-up.  Before replacing a component part, first disconnect the power supply lead wire from the unit
2) All equipment, measuring instruments and tools must be grounded.
3) The workbench should be covered with a conductive sheet and grounded.
When removing the laser pick-up from its conductive bag, do not place the pick-up on the bag. (This is because there is the possibility of damage by static electricity.)
4) To prevent AC leakage, the metal part of the soldering iron should be grounded.
5) Workers should be grounded by an armband (1 MW)
6) Care should be taken not to permit the laser pick-up to come in contact with clothing, in order to prevent static electricity changes in the clothing to escape from the armband.
7) The laser beam from the pick-up should NEVER be directly facing the eyes or bare skin.

Do not remove a replacement ESD device from its protective package until immediately before you are ready to install it. (Most replacement ESD devices are packaged with leads electrically shorted together by conductive foam, aluminum foil or comparable conductive materials).
7. Immediately before removing the protective material from the leads of a replacement ESD device, touch the protective material to the chassis or circuit assembly into which the device will by installed.

HIDDEN KEY MODE

Push both Front key and RCU key to activate it for 5 seconds.
1. 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)

SERVICE INFORMATION FOR EEPROM

POWER ON

FLD no disc status or AUX status

Remote control ‘Fwd skip’ + Front ‘STOP’ push same timing during 5 seconds

FLD ‘OP-0…

Move to appropriate position and make changes with remote control ‘skip, mode, play’ key

Press ENTER key

FLD ‘write ok

Remote control ‘Fwd skip’ + Front ‘STOP’ push same timing

FLD ‘E2P CLR

Completed.

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.
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

EQ PROGRAM
Download program file name must be 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

Repair help

NO POWER
If the unit doesn’t work by no power problem, repair the set according to the following guide.
FUSE & BRIDGE DIODE
check and replace F901, BD901, TH901 or TH903 on SMPS board.
How to troubleshoot (Countermeasure)
1) Check if the fuse F901 is open or short-circuit.
2) Check if the bridge diode BD901 is short-circuit by over current with a digital multi meter.
3) 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 guide.
D951
check and replace D951 on SMPS board.
How to troubleshoot (Countermeasure)
1) Check the anode-cathode 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.

NO BOOTING WHEN POWER ON THE SET
The set doesn’t work when press the power button on the front board or the remote control.
FLASH MEMORY
Check and replace IC503 on MAIN board.
How to troubleshoot (Countermeasure)
1) Check 5.6 V to CN501 in standby mode.   If there is no 5.6 V, check the SMPS.
2) Check 12 V, F+, F- and PVDD when power on the set.  - If the set doesn’t work regardless of what the KEY1 changes high to low while pressing the power button.
X500 and X501 work normally but, if you can not power on the set, replace IC501 with a new one on the MAIN board.

VFD is not displayed when power on the set
When power on the set, any icons or characters on VFD are not displayed.
check and replace DIG302 on FRONT board.
How to troubleshoot (Countermeasure)
1) Check if VKK, FL+ and FL- are output from SMPS to VFD via the MAIN board.
2) Check if IC501 outputs VFD_D0, VFD_CLK and VFD_STB to the FRONT board.
3) Check the GR signal (pulse signal) of IC408 on the FRONT board.
Check the SG signal (pulse signal) of IC408 on the FRONT board.
 If the GR and SG signal isn’t output, replace IC408 with a new one.  If the GR and SG signal is output, replace DIG302 with a new one.

NO OPERATION OF MD
When no sound output in the CD function, you can not listen to music reading data from a CD disc if the servo motors in MD don’t work. This step is for checking the SPINDLE MOTOR among them.
check and replace IC407, IC408 on MAIN board.
 How to troubleshoot (Countermeasure)
1) Check the SPDO signal from pin24 of IC407.  If no signal, check 3.3 V(RF) and X400.
2) Check the SPIN- & SPIN+ from IC408 to CN405 for driving SPINDLE motor. It is about 3.6 Vp-p. If no signal, check +1.8 V and +5 V for IC408.
3) Check if the FFC cable is solidly connected between CN405 and MD.
4) Check the MD. If the spindle motor is sort-circuit or has any trouble, it can not rotate CD discs.
check the function after changing another MD.

NO OPERATION OF MD
When no sound output in the CD function, you can not listen to music reading data from a CD disc if the servo motors in MD don’t work. This step is for checking the SLED MOTOR among them.
check and replace IC407, IC408 on MAIN board.
 How to troubleshoot (Countermeasure)
1) Check the SLDO signal from Pin23 of IC407.  If no signal, check 3.3 V(RF) and X400.
2) Check the SLED+ & SLED- from IC408 to CN405 for driving SPINDLE motor. It is about 2.9 Vp-p. If no signal, check +1.8 V and +5 V for IC408.
3) Check if the FFC cable is solidly connected between CN405 and MD.
4) Check the MD. If the sled motor is sort-circuit or has any trouble, it can not move the pickup module.
check the function after changing another MD

NO OPERATION OF MD
When no sound output in the CD function, you can not listen to music reading data from a CD disc if the servo motors in MD don’t work. This step is for checking the TRAY OPEN / CLOSE MOTOR among them.
 TRAY OPEN / CLOSE MOTOR
check and replace IC407, IC408 on MAIN board.
How to troubleshoot (Countermeasure)
1) Check MOT_OPEN & MOT_CLOSE signals from Pin K4, L4 of IC501 to IC408.  If no signal, check +1.8 V & + 5 V to IC408.
2) Check LOAD± from IC408 to CN405 for driving the tray open / close motor. It is about 3.85 Vp-p. If no signal, check +5 V to IC408. If it has any trouble, replace it with a new one.
3) Check if the FFC cable is solidly connected between CN405 and MD.
4) Check the MD.  If the tray motor is sort-circuit or has any trouble, it can not open or close the tray.
check the function after changing another MD.

NO OPERATION OF MD
When no sound output in the CD function, you can not listen to music reading data from a CD disc if the pickup module in MD doesn’t work. This step is for checking the LASER TRACKING ACTUATOR.
check and replace IC407, IC408 on MAIN board.
How to troubleshoot (Countermeasure)
The tracking actuator makes the laser beam be positioned in the center of a track on CD disc.
1) Check the TRD signal from Pin22 of IC407.  If no signal, check 3.3 V(RF) and X400.
2) Check TR- & TR+ from IC408 to CN408 for driving the tracking actuator.  If no signal, check +1.8 V and +5 V for IC408.

3) Check if the FFC cable is solidly connected between CN405 and MD.
4) Check the MD. If the pickup module has any trouble, it can not move the laser beam on the left or right side.
check the function after changing another MD.

NO OPERATION OF MD
When no sound output in the CD function, you can not listen to music reading data from a CD disc if the pickup module in MD doesn’t work. This step is for checking the LASER FOCUSING ACTUATOR.
check and replace IC407, IC408 on MAIN board.
How to troubleshoot (Countermeasure)
The focusing actuator makes the laser beam keep a regular interval with the surface of a CD disc.
1) Check the FOD signal from Pin21 of IC407.  If no signal, check 3.3 V(RF) and X400.
2) Check F- & F+ from IC408 to CN405 for driving the focusing actuator.  If no signal, check +1.8 V and +5 V for IC408.
3) Check if the FFC cable is solidly connected between CN405 and MD.
4) Check the MD. If the pickup module has any trouble, it can not move the laser beam on the top or bottom side.
check the function after changing another MD.

NO SOUND
There is no sound output in the CD FUNCTION, repair the set according to the following guide.
IN THE CD FUNCTION
check and replace IC501, IC601 on MAIN board.
How to troubleshoot (Countermeasure)
1) Check CD_BCLK, CD_LRCK, & CD_DOUTA signals from IC407 to IC501.  If no signal, check if the RF & servo signals from MD is entered to IC407.
Refer to the “No operation of MD” guide on Item 4.
2) Check the following I2S signal flow. < I2S audio signal Interface >
- DAC_BCK : IC501_Pin E1 --> IC601_Pin23
- DAC_LRCK : IC501_Pin D1 --> IC601_Pin22 (44.1 kHz)
- DAC_DATA : IC501_Pin E2 --> IC601_Pin24
- DAC_MCLK : IC501_Pin D2 --> IC401_Pin44
 If there is any trouble, check the power for each IC. The power is normal but, if the signal waveform to the IC is distorted or no signal, replace it with a new one.
3) check if “Digital audio AMP block” on Item 5-2 is normal.

NO SOUND
There is no sound output by DIGITAL AUDIO AMP DAMAGE, repair the set according to the following
BY DIGITAL AUDIO AMP DAMAGE (IN ALL FUNCTIONS)
check and replace IC701, IC702 on MAIN board.
How to troubleshoot (Countermeasure)
1) Check PWM_FL±, PWM_FR± & PWM_SW± signals from IC601 to IC701 & 702 each input function.  If no signal, check if I2S audio signals are entered to IC601.
Refer to “I2S audio signal interface” on Item 5-1.
2) Check PVDD. If PVDD is abnormal, check the SMPS.
3) Check +12 V for driving the gate of AMP IC.
a. All the powers are normal, but if +12 V is low, there is possible for AMP IC to be damaged.
b. Remove L701, L702, L703 and L704 one by one.
When removed a inductance, if +12 V is recovered, the IC connected to it was damaged.  c. Replace the IC with a new one.
4) Check the impedance between IC701/IC702_OUT_A/OUT_B & GND.
a. If the impedance is 0 Ω, the IC must be damaged.
b. After removing the heat sink, replace it with a new one.

NO SOUND
There is no sound output in the USB FUNCTION, repair the set according to the following
IN THE USB FUNCTION
Check and replace IC501 on MAIN board & IC302 on USB board.
How to troubleshoot (Countermeasure)
1) Check +5V_USB to USB board.  If the USB LED are turned on, the voltage is okay, if so not, check +5.6 V to pin6 of CN302.
2) Check USB D1± or USB D2± from MAIN board to USB board.
a. Check 2.0_D1±signals (pin U7, U8 ) or 1.1_D1± signals(pin A7, A8 ) to IC501.
b. Check USB± signals to CN302 (pin1, 2, 4, 5).  If there is any trouble, check the power for each IC. The power is normal but , if the signal waveform to
the IC is distorted or no signal, replace it with a new one.
3) check if “Digital audio AMP block” on item 5-2 is normal.

NO SOUND
There is no sound output in the AUX FUNCTION, repair the set according to the following

Check and replace IC201 on MAIN board.
How to troubleshoot (Countermeasure)
1) Check AUX_L/R signals to IC201 (Pin23, 24).
2) Check if MCS_BCK, MCS_LRCK & MCS_MCLK are entered from IC501 to IC201.
3) Check if ADC_DATA is entered from IC201 to IC501.  If no signal, check +5 V & +3.3 V(ADC) for IC201. If is NG, replace it a new one.
4) Check the following I2S signal flow from IC801 to IC602. If there is any trouble, check the power for each IC. The power is normal but, if the signal waveform to the IC is distorted or no signal, replace it with a new one.
5) Check if the digital audio AMP block is okay. If AMP is damaged, replace it with a new one.

There is no sound output in the TUNER FUNCTION, repair the set according to the following guide.
IN THE TUNER FUNCTION
check and replace IC201, TU500 on MAIN board.
How to troubleshoot (Countermeasure)
1) Check if TUNER_LR is entered from Pin1, 3 of TU500 to IC201(Pin26, 27).  If no signals, check +3.3 V for tuner power.
 Check if the tuner control signals (CLK, DAT, CE, RST, SLT) are entered from IC501 to TU500.
If it doesn’t work, replace TUNER with a new one.
2) Check if MCS_BCK, MCS_LRCK, & MCS_MCLK are entered from IC501 to IC201.
3) Check if ADC_DATA is entered from IC201 to IC501. If no signal, check +5 V & +3.3 V(ADC) for IC201. If is NG, replace it with a new one.
4) Check the following I2S audio signal flow from IC501 to IC601. If there is any trouble, check the power for each IC. The power is normal but, if the signal waveform to the IC is distorted or no signal, replace it with a new one.
5) Check if the digital audio AMP block is okay. If AMP is damaged, replace it with a new one.

NO SOUND
There is no sound output in the PORTABLE FUNCTION, repair the set according to the following guide.
IN THE PORTABLE FUNCTION
check and replace IC201 on MAIN board.
How to troubleshoot (Countermeasure)
1) Check PT_L/R signals to IC201 (Pin9, 10).
2) Check if MCS_BCK, MCS_LRCK, & MCS_MCLK are entered from IC501 to IC201.
3) Check if ADC_DATA is entered from IC201 to IC501. If no signal, check +5 V & +3.3 V(ADC) for IC201. If NG, replace it a new one.
4) Check the following I2S signal flow from IC501 to IC601. If there is any trouble, check the power for each IC. The power is normal but, if the signal waveform to the IC is distorted or no signal, replace it with a new one.
5) Check if the digital audio AMP block is okay. If AMP is damaged, replace it with a new one.

WAVEFORMS OF MAJOR CHECK POINTs

SMPS and Power amplifier schematic