HOME AUDIO SYSTEM Sony MHC-V44D disassembly procedure, SMPS troubleshooting table

Speaker system

3-way, Sound Pressure Horn

Speaker unit

Tweeter L/R: 40 mm, cone type

Midrange L/R: 80 mm, cone type

Woofer: 200 mm, cone type

Rated impedance

Tweeter L/R: 4 ohms

Midrange L/R: 4 ohms

Woofer: 2 ohms

  The laser diode in the optical pick-up block may suffer electrostatic break-down because of the potential difference generated by the charged electrostatic load, etc. on clothing and the human body.
  During repair, pay attention to electrostatic break-down and also use the procedure in the printed matter which is included in the repair parts.
The flexible board is easily damaged and should be handled with care.

The laser beam on this model is concentrated so as to be focused on the disc reflective surface by the objective lens in the optical pickup block. Therefore, when checking the laser diode emission, observe from more than 30 cm away from the objective lens.

If “protectx” (x is a number) appears in the display panel
Immediately unplug the AC power cord (mains lead), and check the following items.
• Is anything blocking the ventilation holes of the unit?
• Is the USB port short-circuited?
After checking the above items and fixing any problems, plug in the AC power cord (mains lead) again and turn on the system.

Releasing the disc tray lock
The disc tray lock function for the anti-theft of an demonstration disc in the store is equipped.

Releasing Procedure:
1. Press Power button to turn the power on.
2. Press the [FUNCTION] button until the message “DVD/CD” is displayed.
3. Press the [ENTER] button and [VOCAL FADER] button simultaneously and hold down for around 3 seconds.
4. The message “UNLOCKED” is displayed and the disc tray is unlocked.
Note: When “LOCKED” is displayed, the slot lock is not released by turning power on/off with the Power button.

Note of replacing the ic2002 and ic2003 on the damp board and the complete damp board
When IC2002 and IC2003 on the DAMP board and the complete DAMP board are replaced, it is necessary to spread the compound between parts and heat sink.

How to open the tray when power switch turn off
Note 1: After the side panel and top panel are removed, this work is done.
Note 2: Prepare the thin wire (clip etc. processed to the length of 8 cm or more).

Disassembly 

Back panel section

Front panel disassembly

Speaker disassembly

Optical device disassembly

SMPS board diagnosis

ROTEL RA 980BX STEREO AMPLIFIER REPAIR ASSISTANCE

Fault: No output from left channel. The right Channel is working fine.

Added some photos and circuit for reference  

While testing the amp noticed that the left channel is giving switch on off thump while powering ON and OFF the amplifier. It happens when there is DC voltage flow through the speakers. It shouldn't be there. And the thump is there only on the left channel. While testing the amplifier section found that all the transistors where idling at mentioned voltage. All Base pins where around +/- 0.5volt. and the output is almost 0.012mvdc.

As the amplifier had an external Pre -IN, Pre -out coupling it was easy to use an external pre amp to test the amplifier section.

 While testing with an external pre amp found that the amplifier section is OK. There were no switch off thump too while working through the external pre amp.

After testing the amplifier stage and confirming it is OK, turn to the next stage. The internal pre amp (tone control) section.

The internal pre amp of Rotel RA 9808X is built with two AD712JN ICs. Where each AD712 is used for the left and right channel separately. Hope Rotel did it to reduce the bleeding between the left and right channel. Its possible to reduce the bleeding between two channels. If we use two op amps separately for each channels than using the half of each.

While testing the pre amplifier it is found that there was a DC voltage of 15V at the pin no 7 (output pin) of one of the AD712 which is used for the left channel. It shouldn’t be there. The output, non inverting and inverting pins of an op amp which is used in the tone stage circuit should be at 0vdc ,if it’s working in dual supply rail (+/- supply).  And there was no voltage found on the pin 7 of other AD712 which is used for the right channel.  While further treating found that the supply voltages to AD712 where ok its there it +/- 17.5V.  

As there was nothing else to check, replace the AD712 with a new one. Then power the amplifier and found that it’s working perfectly. There were no voltages where found on the pin no 7. And also there were no switch of thump too. Also replaced the power filter capacitor and coupling capacitors near the AD712 of each channel as it is found bad.

If AD712 is not available then Instead of AD712 you can use TLO82. It is an equivalent to AD712. Or you can use NE4558 , it will work too but  there will be some difference in frequency response of the amplifier, but not that much noticeable. If your customer is not an audiophile then it’s ok.  

Circuit diagram of ROTEL RA 980BX

TONE 1/2

TONE 2/2

POWER AMP 1/2

POWER AMP 2/2

Power amplifier bias adjust

Prior to adjustment run the amplifier for about 5 minutes with load resistance of 8ohms

SETP	PLUS LEAD	MINUS LEAD	ADJUST	ADJUST FOR
1	TP3	TP1	VR601	DC MILLIVLOT 10mv
2	TP4	TP2	VR602

How to disassemble Apple Mac Mini – how to remove the case – How to remove the logic board

How to remove and replace the optical diver -  How to disassemble Apple Mac Mini – how to remove the case – How to remove the logic board - Apple Mac Mini

Place your thumbs in the depressions cut into the bottom cover. Rotate the bottom cover counter-clockwise until the white dot painted on the bottom cover is aligned with the ring inscribed on the outer case.

Tilt the mini enough to allow the bottom cover to fall away from the outer case. Remove the bottom cover and set it aside.

Remove the two 11.3 mm T6 Torx screws securing the fan to the logic board near the antenna plate.

Lift the ear of the fan nearest the RAM up off the standoff secured to the outer case.

Lift the fan out of the mini for enough clearance to access its connector. Carefully pull the fan cables upward to lift the fan connector up out of its socket on the logic board. Remove the fan.

Remove the single 3.5 mm T6 Torx screw securing the cowling to the heat sink.

Lift the cowling from the end nearest the antenna plate. Rotate the cowling away from the outer case and remove it from the mini. Remove the following screws securing the antenna plate to the mini:

Two 6.6 mm T8 Torx screws Two 5.0 mm T8 Torx or 2.0 mm Hex screws (either will work)
Slightly lift the antenna plate from the end closest to the RAM. Carefully pull the antenna plate straight away from the circular rim of the outer case. Do not remove the antenna plate yet. It is still attached to the AirPort/ Bluetooth board.

Use the tip of a spudger to carefully pry the antenna connector up off the AirPort/Bluetooth board.

Remove the antenna plate from the mini.

Logic Board Removal

Remove the following three screws One 5.0 mm T8 Torx or 2.0 mm Hex screw (either will work)
One 16.2 mm T6 Torx screw
One 26 mm T6 Torx standoff

Carefully pull the wires for both hard drive thermal sensors upward to lift their connectors up and out of the sockets on the logic board.

Use the flat end of a spudger to pry both the hard drive and optical drive connectors up out of their sockets on the logic board.

To disconnect the optical drive hermal sensor, pinch its cables between your thumb and a spudger and pry the spudger upward to lift he connector up and out of its socket on the logic board.

Use the tip of a spudger to lift the IR sensor connector up and out of its socket on the logic board.

To remove the logic board, two cylindrical rods must be inserted into the holes highlighted in red. Inserting instruments into any logic board holes other than the ones highlighted in red may destroy the logic board.

Insert a Mac Mini Logic Board Removal Tool into the two holes highlighted in red. Be sure it makes contact with the outer case below the logic board before proceeding. If you don't have a Logic Board Removal Tool handy, you can use two tools having a maximum diameter of 2.5 mm instead. Just insert one into each of the highlighted holes.
Carefully pull the tool toward the I/O board. The logic board and I/O board assembly should slightly slide out of the outer case. Cease prying when the I/O board is visibly separated from the outer case. Remove the Mac Mini Logic Board Removal tool.

Simultaneously push the two plastic clips on the far left and right sides of the I/O board toward the middle of the I/O board and pull the I/O board away from the outer case. Pull the I/O board/logic board assembly out of the outer case enough to access the power connector. Use a pair of tweezers to disconnect the power cable from the logic board.

Carefully slide the logic board assembly out of the mini, minding any cables that may get caught. Remove the 7.9 mm T6 Torx screw securing the power supply and optical drive to the outer case.

Pull the silver metal AC-In socket retainer away from the side of the outer case and remove it from the mini.

Rotate the AC-In connector 90 degrees counter-clockwise.

Slide the power supply out of the mini, minding any cables that may get caught. Remove the hard drive from the mini, minding any cables that may get caught.

Remove the 7.9 mm T6 Torx screw securing the optical drive to the outer case. Slide the optical drive out of the outer case, minding any cables that may get caught.

Carefully de-route the IR sensor cables from the channel in the optical drive bracket.

Remove the two 6.3 mm T6 Torx screws securing both sides of the optical drive bracket to the optical drive (four screws total).

Remove the optical drive bracket from the optical drive, minding any cables that may get caught. Carefully peel the optical drive ribbon cable off the body of the optical drive.

Disconnect the optical drive cable by pulling its connector away from the body of the optical drive. Peel off the strip of black tape covering the optical drive thermal sensor.

Carefully pry the optical drive thermal sensor off the adhesive securing it to the optical drive. It may be necessary to use a strip of tape or rubber cement to attach the thermal sensor to your new optical drive.

How to test the AC charger – How to remove the battery pack – How to remove the mother board - Lenovo IdeaTab A2107

How to disassemble Lenovo IdeaTab A2107

To verify a symptom, follow the steps below:
1. Turn off the computer.
2. Remove the battery pack.
3. Connect the AC adapter.
4. Make sure that power is supplied when you turn on the computer.
5. Turn off the computer.
6. Disconnect the AC adapter and install the charged battery pack.
7. Make sure that the battery pack supplies power when you turn on the computer.
If you suspect a power problem, see the appropriate one of the following power supply checkouts:
“Checking the IdeaTab AC Charger”
“Checking the internal battery status”
Checking the IdeaTab AC Charger
When you use the IdeaTab AC Charger to charge the tablet but no power is charged, see the instructions in this topic to check the IdeaTab AC Charger.
To check the IdeaTab AC Charger, do the following:
1. Disconnect the micro-USB cable from the tablet.
2. Measure the output voltage across the connector marked B of the micro-USB cable. Refer to the following figure:

Note: The output voltage across pin 3 of the micro-B connector might be different from the one you are servicing.

3. If the voltage is not correct, replace the micro-USB cable.

4. If the voltage is acceptable, replace the system board.
Checking the internal battery status
To check the battery status of the tablet, do either of the following:
Approximate information about the battery status
Get the approximate status of the battery at any time by checking the battery status icon on the system bar in the upper-right corner of the screen. The shorter the green bar is, the less the battery power remains.
Accurate information about the battery status
To get the accurate information about the battery status of the tablet, do the following:

1. Open the Android Settings screen.
To open the Android Settings screen, do either of the following:
From the main Home screen, touch the Android Settings icon on
Lenovo Launch Zone. The Android Settings screen is displayed. Touch the application icon from the action bar and then touch Settings.
The Android Settings screen is displayed.
2. Touch About Tablet on the Android Settings screen.
3. Touch Status to view the accurate percentage of the remaining battery power. You also can touch Battery use to check what applications are consuming battery power.

Disassembling procedure 

How to remove Battery pack

Remove screw 1 and push the battery pack backward in the direction shown by arrow 2.

How to remove Base cover

Remove 16 screws 1 on the base cover with the screw driver

Remove the base cover in the direction shown by arrow 3.

Disconnect the battery connector 3 , insert a flat blade under the bottom right of the battery and carefully pry out the battery in the direction as shown below.

How to remove System board

Remove two screws 1.

Peel off the microphone 4 , vibrator 9 , speakers 10, detach the LCD connector 2, touch connector 3, USB board connector 5, back camera connector 6, power button board connector 7,volume up/down button connector 8.

Remove the system board in the direction shown by arrow 11 .

HP EliteBook 820 G3 Notebook – Disassembling procedure – How to remove the battery – How to remove the – Bottom case – How to remove the HDD

HP EliteBook 820 G3 Notebook disassembling procedure 

How to remove Bottom cover

Before removing the bottom cover, follow these steps:
1. Turn off the computer. If you are unsure whether the computer is off or in Hibernation, turn the computer on, and then shut it down through the operating system.
2. Disconnect the power from the computer by unplugging the power cord from the computer.
3. Disconnect all external devices from the computer.
Remove the bottom cover:
1. Turn the computer upside down on a flat surface.

2. Remove the 11 rubber plugs (1) and the 11 Phillips PM2.5x5.0 screws beneath them (2) from the bottom cover.
Be sure to remove the screws in the following order.

3. Remove the SD card blank and the 1 PM2.0×7.0 screw beneath it (3) that secures the bottom cover to the computer.

4. Pry up on the top (near the display hinge) of the bottom cover to disengage it from the computer (4).

How to remove Battery

Before removing the battery, follow these steps:
1. Turn off the computer. If you are unsure whether the computer is off or in Hibernation, turn the computer on, and then shut it down through the operating system.
2. Disconnect the power from the computer by unplugging the power cord from the computer.
3. Disconnect all external devices from the computer.
4. Remove the bottom cover
To remove the battery:

Loosen the captive screw (1) and lift the tab to remove the battery from the computer (2).

How to remove Hard drive

Before removing the hard drive, follow these steps:
1. Shut down the computer. If you are unsure whether the computer is oƫ or in Hibernation, turn the computer on, and then shut it down through the operating system.
2. Disconnect all external devices connected to the computer.
3. Disconnect the power from the computer by ƭrst unplugging the power cord from the AC outlet, and then unplugging the AC adapter from the computer.
4. Remove the bottom cover
5. Remove the battery
To remove a hard drive:
1. Loosen the 4 captive screws (1) that secure the hard drive to the chassis.
2. Slide the hard drive (2) away from the center of the computer to disengage it from the connector.
3. Lift to remove the hard drive from the bay (3).

How to remove SSD

Before removing the SSD, follow these steps:
1. Turn oƫ the computer. If you are unsure whether the computer is oƫ or in Hibernation, turn the computer on, and then shut it down through the operating system.
2. Disconnect the power from the computer by unplugging the power cord from the computer.
3. Disconnect all external devices from the computer.
4. Remove the bottom cover
5. Disconnect the battery
Remove the SSD:
1. Remove the Phillips PM2.0×3.0 screw (1) that secures the drive to the system board.

2. Remove the drive (2) by pulling it away from the connector.

How to remove the Keyboard

Before removing the keyboard, follow these steps:
1. Shut down the computer. If you are unsure whether the computer is oƫ or in Hibernation, turn the computer on, and then shut it down through the operating system.
2. Disconnect all external devices connected to the computer.
3. Disconnect the power from the computer by ƭrst unplugging the power cord from the AC outlet, and then unplugging the AC adapter from the computer.
4. Remove the bottom cover
5. Remove the battery
Remove the keyboard:
1. Remove the 2 Phillips PM2.5×3.0 screws that secure the keyboard to the computer (1).
2. Position the computer upright with the front toward you.
3. Open the computer as far as possible.

4. Insert a screwdriver or similar thin tool into the hole beside the heat sink/fan assembly, and then press on the back of the keyboard until it disengages from the computer (2). Rotate the top of the keyboard upward, and then lift the keyboard up at an angle to disengage the tabs at the bottom of the keyboard.

5. Slide the keyboard slightly downward toward the palm rest to disengage the top of the keyboard from the top cover (1). Remove the pointing stick cable (2), the keyboard backlight cable (3), and the keyboard cable (4).

6. Remove the keyboard (5).

Samsung Galaxy tab GT-P7500 - Troubleshooting procedure - Power on problem and troubleshooting - Battery Charging problem

Samsung Galaxy  GT-P7500 troubleshooting 

Abnormal charging part

Check C514 whether voltage reading is greater than 5V

Check the TA and the DLC (TA or DLC may not be connected properly)

Check C510 whether voltage reading is greater than 5V

Check U507 chip (U507_OVP chip may not work)

Check C749 whether voltage reading is greater than 4.2V

Check U704 chip (U704 chip may not work at room temperature)

Check battery voltage is change when TA is connected

Check U704 chip (U704 chip may not work)

Check C743 whether voltage is change when TA is connected

Check U704 chip (U704 chip may not work)

Microphone Part

Check main microphone function
in voice call receiver mode

Check the voltage at
C406 = 2.8V

Resolder or replace U404

Check component soldering
statuses of C426, C427

Resolder or replace C426, C427

Speaker Part

Check the signals on R427,R428,R338, R338

Resolder or replace U404

Replace the speaker module

BT/WIFI

BT/WiFi is not working

Check BT or WiFi function

Enable BT or WiFi Function

Check the Voltage on C260 = 1.8V

Check AP PMIC(U703)

Check 37.4MHz Clock at R213

Check OSC202

Check the Voltage on L214 = 1.5V

Resolder or change L214

Check the Status of C282, ANT202

Resolder or Replace C282, ANT202

Resolder or Replace U204

Power On does not work

Check "Power on" by power cable with jig-on

Check the switch circuit, FET gate voltage, FET voltage

Check the 30pin to 50pin FPCB(SLC500), Wrong assembly or Wrong connection.

Check the Battery Voltage is more than 3.6V

Charge the Battery (Battery power is low)

Check U703(PMIC) and Power on voltage(C727≥1.2V, C734 ≥1.2V, C730≥1.8V, C725≥ 1.8V, C728≥1.1V, C723≥3.3V, C720≥2.85V)

Check U703. Change the problem point. (short, open, crack, etc.)
If PMIC has problem, change U703

Check U702(_RESET). this pin has to go high level(about 2V),and to go low level after 480ms
Check U6006(A1,Y1). If you push the power on button ,, A1,Y1 has to go high level.

Check the Clock at OSC700(C718) that frequency is 32K

Check the clock generation circuit (related to OSC700)

check the initial operation

TSP

Touch Screen does not work

Check TSP Connector on Main PBA

Reconnect the SLC1000

U1004 Pin64 = 3.3V(C1033) and Pin8 = 1.8V(C1029)

Resolder or Replace U1004 U1001,1002,1003 Pin A1 = 3.3V(C1000,C1006,C1012)

Resolder or Replace U1001,1002,1003

Check the I2C signal of

Sensor IC(R6050, R6051)

Resolder R6050, R6051

Replace TSP Module

3 MEGA PIX CAM

"Camera" function does not work

Check the Camera connector on Main PBA

Reconnect the HDC900

Check the voltage
C902 = 1.2V
C901 = 2.8V
C913 = 1.8V
C900 = 1.8V

Resolder U900,R900,R902,L900
Resolder U901
Resolder U902
Replace the PBA

Check R903 is 24MHz

Resolder R903 Replace the PBA

Check the I2C line TP902 & TP903 = HIGH

Resolder R6044, R6045 Replace the PBA

Check F900 is OK

Resolder F900 Replace the PBA

Replace the camera module

Initial Failure

CP_RST(R320), PDA_ACTIVE(R6067) >= 1.8V(HIGH)

Check UCP6000 (short, crack, etc.)

CP_ON(TP_CP_ON), PHONE_ACTIVE(TP6024)>= 1.8V(HIGH)

Check UCP300 (short, crack, etc.)

AP_nRST(U703_pin #G8,TP702) "low -> high"?

Replace OSC 300 and OSC700

There are 26MHz wave forms at OSC600(C6082) and 26MHz wave forms at OSC100(C150)

Replace OSC600 and OSC100

LCD display OK?

Check the LCD part(short, crack, etc.)

Sound is OK?

Check the Audio Part(short, crack, etc.)

LCD

LCD is still off after PWR ON

Check the connection of SLC800

Reconnect the SLC800

Check the C818 and High(18V)

Check the Backlight Driver IC(U805)

Check C821 = 1.8V, C823 = 3.3V, C833= 1.2V

Check the LDO(802) DC-DC(U803) DC-DC(U804)

Check the signal DISPLAY_PCLK(TP809) LCD_D(0)(TP801)

Check the IC UCP6000

Check the signal IDISPLAY_PCLK(TP806) LCD_F(0)(TP800)

Check the freq of C813(19.2MHz)

Replace or resolder OSC800

Check the U801

Check C800 = 1.8V, C801 = 3.3V

Check the IC U800

Replace LCD Module

HP Pavilion 11 X2 – dissembling procedure – How to remove the display – How to remove the RTC battery

Disassembling procedure 

How to remove Display enclosure

Before disassembling the tablet, follow these steps:
1. Turn off the tablet. If you are unsure whether the tablet is off or in Hibernation, turn the tablet on, and then shut it down through the operating system.
2. Disconnect the power from the tablet by unplugging the power cord from the tablet.
3. Disconnect all external devices from the tablet.
Remove the display enclosure:

1. Place the tablet on a flat work surface, with the display screen facing down and the rear-facing webcamera toward you.
2. Lift up on the top edge of the display enclosure (1) until the tabs built into the enclosure release from the display panel assembly.

3. Remove the display enclosure (2) from the tablet

How to remove Sensor board

Before removing the sensor board, follow these steps:
1. Turn off the tablet. If you are unsure whether the tablet is off or in Hibernation, turn the tablet on, and then shut it down through the operating system.
2. Disconnect the power from the tablet by unplugging the power cord from the tablet.
3. Disconnect all external devices from the tablet.
4. Remove the display enclosure

Remove the sensor board:
1. Disconnect the tablet battery cable from the system board.

2. Disconnect the sensor board cable (1) from the system board.

3. Disconnect the power button board cable (2) from the sensor board.

4. Detach the sensor board (3) from the display panel assembly. (The sensor board is attached to the display panel assembly with double-sided tape.)

5. Remove the sensor board.

Reverse this procedure to install the sensor board.

How to remove Wireless antenna

Before removing the wireless antenna, follow these steps:
1. Turn off the tablet. If you are unsure whether the tablet is off or in Hibernation, turn the tablet on, and then shut it down through the operating system.
2. Disconnect the power from the tablet by unplugging the power cord from the tablet.
3. Disconnect all external devices from the tablet.
4. Remove the display enclosure
5. Disconnect the tablet battery cable from the system board

Remove the wireless antenna

1. Disconnect the WLAN antenna cables (1) from the terminals on the WLAN module.

2. Release the wireless antenna cables from the routing clips (2) built into the display panel assembly.
3. Detach the wireless antenna transceivers (3) from the heat sink. (The wireless antenna
transceiver is attached to the heat sink with double-sided tape.)

4. Remove the wireless antenna cables and transceivers. Reverse this procedure to install the wireless antenna cables and transceivers.

How to remove Front-facing web camera

Before removing the front-facing web camera, follow these steps:
1. Turn off the tablet. If you are unsure whether the tablet is off or in Hibernation, turn the tablet on, and then shut it down through the operating system.
2. Disconnect the power from the tablet by unplugging the power cord from the tablet.
3. Disconnect all external devices from the tablet.
4. Remove the display enclosure
5. Disconnect the tablet battery cable from the system board
Remove the front-facing web camera:
1. Release the ZIF connector (1) to which the front-facing web camera cable is attached, and then disconnect the front-facing web camera cable from the system board.
2. Remove the Phillips PM1.85×1.60 screw (2) that secures the front-facing web camera bracket to the display panel assembly.
3. Swing the right side of the bracket (3) up and to the left until the bracket releases from the tab
(4) built into the display panel assembly.
4. Remove the front-facing web camera (5).

How to remove RTC battery

Before removing the RTC battery, follow these steps:
1. Turn off the tablet. If you are unsure whether the tablet is off or in Hibernation, turn the tablet on, and then shut it down through the operating system.
2. Disconnect the power from the tablet by unplugging the power cord from the tablet.
3. Disconnect all external devices from the tablet.
4. Remove the display enclosure
5. Disconnect the tablet battery cable from the system board
Remove the RTC battery:
1. Disconnect the RTC battery cable (1) from the system board.
2. Detach the RTC battery (2) from the display panel assembly. (The RTC battery is attached to the display panel assembly with double-sided tape.)