SONY MHC-V71D HOME AUDIO SYSTEM DISASSEMBLY, TEST MODES, SMPS BOARD FAULT DIAGNOSIS

Sony HOME AUDIO SYSTEM MHC-V71D disassembly, test modes, SMPS board fault diagnosis

How to disassemble Sony MHC V71 home audio system, test modes, how to take the disc out at emergency, Power board fault diagnosis

US Model, Canadian Model-MHC-V71

AEP Model, UK Model, E Model, Australian Model-MHC-V71D

Destination setting method
The destination information isn’t written in the MOTHERBOARD board for the service.
Therefore, when the MOTHERBOARD board is replaced, be sure to perform the destination setting (Important work).

Note 1: The initial setting destination of the MOTHERBOARD board for the service is temporary set as “LATIN”. The message “LATIN (T)” is displayed on the screen display panel.
Note 2: When distinguishing the destination of the product, refer to the “MODEL IDENTIFICATION”
Note 3: If destination setting isn’t performed, it is possibility to occur the defect to each operation of this unit.
Note 4: Destination would be locked if it has changed for 5 times.

Touch two touch keys of the [FIESTA] and { TUNING + >>| } simultaneously for 10 seconds during the demonstration mode.
2. It enters the destination setting mode, the message "D XXXXX" is displayed on the screen display panel.
Note 5: If the message "DESTLOCK" is displayed on the screen display panel, touch the [>] touch key to release from this mode.
Because the destination is locked, and it cannot change the destination..

3. Touch [ 0+ ] / [ - ] touch key to select the destination based on the set's country.

4. Touch [ > ] touch key to confirm the selection.
5. "RESET" appears on the screen display panel. After that, "SONY “appears on the screen display panel. The system automatically turn on and off once. Please be sure that the system stay at demo mode finally before switch off the power supply.
6. Mode in "MODEL, DESTINATION AND VERSION DISPLAY MODE" again to confirm on the model & destination.

Power output and total harmonic distortion:

(US models only)

With 4 ohm loads, both channels driven, from 400 Hz – 20,000 Hz; rated 60 watts per channel minimum RMS power, with no more than 0.7% total harmonic distortion from 250 milliwatts to rated output.

Speaker section

3-way, Double Bass Reflex Speaker unit:

Tweeter L/R: 50 mm (2 in), cone type

Midrange L/R: 120 mm (4 3/4 in), cone type

Woofer: 300 mm(11 7/8 in), cone type

Supported audio formats

Supported bit rate and sampling frequencies:

MP3:

32/44.1/48 kHz, 32 kbps –

320 kbps (VBR)

AAC:

44.1 kHz, 48 kbps – 320 kbps

(CBR/VBR)

WMA:

44.1 kHz, 48 kbps – 192 kbps

(CBR/VBR)

WAV:

44.1/48 kHz (16 bit)

Supported video formats (V71D)

Xvid:

Video codec: Xvid video

Bit rate: 4.854 Mbps (MAX)

Resolution/Frame rate:

720 × 480, 30 fps

720 × 576, 25 fps (except for Latin American model)

Audio codec: MP3

MPEG4:

File format: MP4 File Format

Video codec: MPEG4 Simple

Profile (AVC is not compatible.)

Bit rate: 4 Mbps

Resolution/Frame rate:

720 × 480, 30 fps

720 × 576, 25 fps (except for Latin

American model)

Audio codec: AAC-LC (HE-AAC is

not compatible.)

DRM: Not compatible.

When disassembling the set, use the following jig (for front panel removal).

Part No.: J-2501-238-A JIG FOR SPEAKER REMOVAL

When the SENSOR board is defective, exchange the SERVICE, TOP PANEL ASSY.

When the MS-476 board is defective, exchange the entire LOADING COMPLETE ASSY (T).

When IC2002 on the MOTHERBOARD board and the complete MOTHERBOARD board are replaced, it is necessary to spread the heat-sink compound between parts and heat sink.

Releasing the disc tray lock
The disc tray lock function for the antitheft of sample disc in the shop is equipped.
It can release the lock function in the following procedure.

Press the [Power] button to turn the power on.
2. Touch the [FUNCTION] touch key to turn the DVD/CD function.
3. Touch [MEGA BASS] and [VOCAL FADER] touch keys simultaneously for three seconds.
4. The message “UNLOCKED” is displayed on the screen display panel and the disc tray is unlocked.
Note: When “LOCKED” is displayed on the screen display panel, the disc tray lock is not released by turning the power on/off with the [Power] button.

IF “PROTECTX” (X IS A NUMBER) AND “CHECK MANUAL” FLASHES ON THE DISPLAY
immediately unplug the AC power cord (mains lead), and check if anything is blocking the ventilation openings of the unit.
After you have checked and found no problems, reconnect the AC power cord (mains lead), and turn on the system. If the issue persists, contact your nearest Sony dealer or the authorized service center.

How to open the tray when power switch turn off/ How to take out the disc in emergency
Note 1: After the side panel L, R are removed, this work is done.
Note 2: prepare the thin wire (clip etc. processed to the length of 8 cm or more)

Remove side panel L, R.
Insert the clip etc. processed to the length of 8 cm or more in the hole on the side of the CDM and push. [Refer to the fig below]

Service position

Disassembly procedure of the side panel

Disassembly procedure of loading panel assembly

Disassembly procedure of the top panel [be very careful not to damage any of the flat cables, while tacking the assembly apart]

Rear cover & ventilation cover disassembly

Disassembly of the back panel section

Disassembly of the CDM section

Optical device [7G] & flexible cable service

Dismantling the Motherboard

SMPS/ the power board removal

Front panel [Vanilla] section disassembly

Bottom cover removal

Test modes

Panel test mode
This mode is used to check the screen display panel, LEDs, buttons, touch keys and GESTURE CONTROL sensor.
1. Press [Power] button to turn on the system.
2. Touch [<] touch key and [MIC/GUITAR LEVEL -] touch key simultaneously for 3 seconds.
3. All LEDs and segments in screen display panel are lighted up.
This is the display check mode.
Touch [ > ] touch key repeatedly to toggle different display mode as below:
Segments on screen display panel:
All On → 1st Group On → 2nd Group On → All On → All Off
Single color LEDs:
All On → All Off → 1st Group On → 2nd Group On → All Off
Multi Color LEDs:
All On → Red → Green → Blue → All Off
4. Touch [0 - ] touch key, the key check mode is activated.
5. In the key check mode, the screen display panel displays “K 0”

Each time a button/touch key is pressed/touched, “K” value increases. However, once a button/touch key has been pressed/touched, it is no longer taken into account. After all the buttons and touch keys have been pressed/touched, “K”
value will toggle between “OK” and “K30”.
The screen display panel displays “<” or “>” or “U” or “u” on the right side of “K30 OK” each time swing left, right, up and down at GESTURE CONTROL.
6. To release from this mode, touch the touch keys in the same manner as step 2, or disconnect the power cord.

Model, destination and version display mode
This mode is used to check the model, destination and software version of the set.
1. Press [Power] button to turn on the system.
2. Touch [<] touch key and [MIC/GUITAR LEVEL -] touch key simultaneously for 3 seconds.
All segments in screen display panel are lighted up.
3. Touch [ +] touch key. Model information appears on the screen display panel.
4. Touch [ +] touch key. Destination information appears on the screen display panel.
5. Touch [ +] touch key. Serial number appears on the screen display panel.
6. During serial number appears, touch [0 +] touch key. Each time [ +] touch key is touched, the screen display panel shows the version of each category software in the following sequence: SC, MTK, BT, BTE, PF, SUB and return back to
model information display.
7. Touch [<] touch key and [MIC/GUITAR LEVEL -] touch key simultaneously for 3 seconds to exit.

User reset
The user reset clears all data including preset data stored in the data flash to initial conditions.
1. Press [Power] button to turn on the system.
2. Touch [GUITAR] touch key and [MEGA BASS] touch key simultaneously for 3 seconds.
3. “RESET” appears on the screen display panel. After that, the screen display panel becomes blank for a while, and the system goes to demo mode.

Cold reset
This mode is used to reset all the user settings to factory setting.
Execute this mode when returning the set to the customer.
1. Press [Power] button to turn on the system.
2. Touch [<] touch key and [MIC/GUITAR LEVEL +] touch key simultaneously for 3 seconds.
3. “COLD RST” appears on the screen display panel. After that, “SONY DEMO” appears on the screen display panel. The system automatically turn on and off once. Please be sure that the system stays at demo mode finally before switch off the power supply.

Disc tray lock
When the disc tray does not open and “LOCKED” appears on the screen display panel, disc tray lock mode has been activated by the shop front.
To release from Disc Tray Lock Mode:
1. Press [Power] button to turn on the system.
2. Touch [FUNCTION] touch key repeatedly to select the DVD/CD function.
3. Touch [MEGA BASS] touch key and [VOCAL FADER] touch key simultaneously and hold down until “UNLOCKED” displayed on the screen display panel.

Shop front demo
The playback started automatically and the “ * DEMO * ” appears on the screen display panel.
This is the Shop Front Demo mode which is activated by the shop front.

Release from Shop Front Demo
1. Touch [<] touch key and [MIC ECHO] touch key simultaneously for 5 seconds.
2. The message "STANDBY" appears on screen display panel.  After that, the screen display panel blinks for a few times and the system goes to demo mode.

SMPS board and fault diagnosis