Sony RMT-V293A, LX70S, RMT-V294A, LX60S, LX40, LX50 service manual ACE Head Adjustment

Page 55

2-4-2. HiFi Switching Position Adjustment (MA-405 Board)

[Adjustment Purpose]

To adjust the link of the A-ch and B-ch of the tape playback outputs. To make the unit compatible with other tapes and units. If this specification is not satisfied, the link will appear on the screen and the screen will be disrupted, etc.

Mode

Playback

 

 

Signal

Alignment tape: SP color bar portion

 

 

Measurement point

CH1: Pin 1 of CN270 (HF ADJ)

 

CH2: Pin 3 of CN270 (RF SWP)

 

 

Measuring instrument

Oscilloscope

 

 

Adjusting element

Remote Commander CH +/–

 

 

Specified value

B=minimize

 

 

[Adjustment Method]

1)Check that “A H” is indicated on FL display.

2)Adjust so that part B becomes minimized at CH +/–.

3)Write data EEPROM by pressing PAUSE button.

4)Check that “A H” indicator turns off.

5)If “A H” indicator is still on, restart RF switching position Adjustment from the beginning.

B

CH1

HFADJ

CH2

RF SWP

Fig. 6-2-5

2-4-3. Normal Audio System Adjustment

•Make adjustment in the SP mode unless otherwise specified. Use a normal VHS cassette for an adjustment tape.

•Set AUDIO MONITOR to normal.

2-4-4. Audio Level and Distortion Check [Adjustment purpose]

Confirm that the audio level and distortion is within the specification.

Mode

REC and PB (SP mode)

 

 

Signal

400 Hz, –7.5 dBs

 

 

Measurement point

Audio output terminal

 

 

Measuring instrument

Audio level meter and distortion

 

meter

 

 

 

 

Specified value

PB level

: –7.5±2dBs (HIFI)

 

PB level

: –7.5±3dBs (MONO)

 

Distortion

: less than 1% (HIFI)

 

Distortion

: less than 4% (MONO)

[Confirmation Method]

1)Supply a signal of 400 Hz, –7.5 dBs to both L and R channels of Audio Line Input.

2)Record the tape.

3)Playback a recorded portion of the tape.

4)Confirm that the playback output level of audio level meter is within of range –7.5±2dBs for HIFI and –7.5±3dBs for MONO.

5)Confirm that the output of distortion meter is less than 1% for HIFI and 4% for MONO.

2-4-5. Audio Noise Check [Adjustment purpose]

Confirm that the noise level is within the specification.

Mode

REC and PB (SP mode)

 

 

Signal

No signal input

 

 

Measurement point

Audio output terminal

 

 

Measuring instrument

Audio level meter

 

 

Specified value

Less than –67,5dBs (HIFI)

 

Less than –45.5dBs (MONO)

[Confirmation method]

1)Audio line input L and R channels are shorted to the ground.

2)Record the tape.

3)Playback a recorded portion of the tape.

4)Confirm that the output level is less than –67.5dBs for HIFI and –45.5dBs for MONO.

2-4-6. ACE Head Adjustment

Refer to the VHS mechanical adjustment manual (S MECHANISM) (9-921-647-11).

2-4-7. E-E Output Level Check

[Adjustment purpose]

Confirm that the output level adjust the reference input is within the specification.

Mode

E-E

 

 

Signal

400 Hz, –7.5 dBs

 

 

Measurement point

CNJ562 L/R

 

 

Measuring instrument

Audio level meter

 

 

Specified value

–7.5 ± 2 dBs

 

 

[Check Method]

1)Input signal of 400 Hz and –7.5 dBs to the CNJ562 L/R.

2)Check that the audio output level is –7.5 ± 2 dBs.

2-4-8. Frequency Response Check

[Adjustment purpose]

Confirm that the frequency characteristic is within the specification.

Mode

REC and PB (SP mode)

 

 

Signal

400 Hz, –17.5 dBs

 

7 kHz, –17.5 dBs

 

 

Measurement point

CNJ562 L/R

 

 

Measuring instrument

Audio level meter

 

 

Specified value

0 ± 3 dB

Note: Tape path adjustment must have been completed.

[Confirmation Method]

1)Supply a signal of 400 Hz, –17.5 dBs to CNJ562 L/R.

2)Connect the audio level meter to CNJ562 L/R.

3)Adjust the attenuator so that the audio level meter will indicate

–17.5 dBs.

4)Make recording in the SP mode.

5)Set an audio line input signal to 7 kHz and make recording.

6)Playback a recorded portion, and measure output levels at 400 Hz and 7 kHz.

7)Confirm that the 7 kHz playback output level within a range of the 400 Hz playback output level 0 ± 3 dB.

6-4

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Contents RMT-V293A/V294A SpecificationsSafety CHECK-OUT Block Diagrams Table of ContentsService Note Disassembly AdjustmentsError Code Indication Service NoteHookups Setting up the remote commanderHookup Hookup 1 VCR setupHookup Antenna hookup Completing A/V hookupAutomatic clock setting Hookup 2 VCR setupHookup Connecting a cable box with many scrambled channels Hookup 3 VCR setupUsing the Auto Clock Set feature Setting the clockSelecting a language If the clock does not activate Using Manual Clock SetPresetting all receivable channels automatically Presetting channelsPresetting/disabling channels manually If the picture is not clear Playing a tapeRecording TV programs Before you start Recording TV programs using the Dial TimerTo watch another TV program while recording To save a recordingAbout the Demonstration Mode Recording TV programs using the timerTo lock the VCR Playing/searching at various speedsLocking the VCR Child Lock To resume normal playbackRecording bilingual programs Setting the recording duration timeChecking/changing/canceling timer settings Recording stereo programsHow sound is recorded on a video tape Searching for the beginning of a timer recorded programSearching using the index function Searching using the Time Search functionSearch forward while Showing the tape contents Fast-forward To cancel skip-searchPress H Play or x Stop About the Adaptive Picture Control APC function Adjusting the pictureAdjusting the tracking Changing menu optionsBefore you start editing How to connect to record on this VCROperation when recording on this VCR Editing with another VCRIndex to parts and controls General setup informationRear panel Display window11--19E CASE, Front Panel Block Assembly SLV-LX40/LX50/LX60S/LX70S Section DisassemblyRear Panel Mechansim Deck Top View Internal ViewsBottom View Circuit Boards Location Overall Block Diagram Video Block Diagram SERVO/SYSTEM Control Block Diagram Tuner Block Diagram Audio Block Diagram Power Block Diagram Xedit → Edit PB/XREC → PB/REC TA aFrame Schematic Diagram VIDEO, AUDIO, SERVO/SYSTEM CONTROL, TUNER, Power REC/PB Head AMP MA-405 REC/PB Head AMP Schematic DiagramSee page 4-21 for waveforms MA-405 BOARD1/7 Audio Process MA-405 Y/C, Audio Processor Schematic DiagramAudio Processor VA Block SERVO/SYSTEM Control SS Block MA-405 SERVO/SYSTEM Control Schematic DiagramSee page 4-5 for printed wiring board MA-405 BOARD4/7 MA-405 Audio Process Schematic DiagramAudio Process AU Block MA-405 BOARD5/7 MA-405 Tuner Schematic DiagramSee page 4-5 for printed wiring board TunerSee page 4-5 for printed wiring board MA-405 BOARD6/7 MA-405 Display Control Schematic DiagramDisplay Control Front Block Power Supply PS Block Power SupplyMA-405 Power Supply Schematic Diagram See page 4-5 for printed wiring board MA-405 BOARD7/7OSD V OUT REC/PBDrum FG Drum PGFJ-32 Board Line 2Line 2 Dial Timer Dial TimerDI-80 Board System Control Mechanism Block Interface MA-405 Board IC160 Signal Pin NoSystem Control Audio Block Interface MA-405 Board IC160 System Control VIDEO/RP Block Interface MA-405 Board IC160Pin Name Function 55-4E Electrical Adjustments Mechanical AdjustmentsPreparation Before Adjustment Input/Output Levels and Impedance Power Supply CheckServo System Check Audio System AdjustmentVTR ACE Head Adjustment RF/HF SWP Adjusting Parts Location DiagramVIDEO/AUDIO Line IN/OUT SW5VFront Panel and Upper Case Section Exploded Views5455 Chassis Section707 708 712 706 702 701 709 704 710 705 722 703 Mechanism Deck721 711 720 713 725 724 714 719 715 717 718 Spring Spring Power TensionBrake ASSY,MAINT Roller ASSY, GuideScrew + P2.6 x 6 TYPE2 NON-SLIT 803 802 833Resistor SwitchSWITCH, Tact LX70SCL,CS ConnectorDouble Layer MA-405Mylar CeramicFilm CONNECTOR, FFC/FPC 7P CONNECTOR, FFC/FPC 5PPIN, Connector 4P HOUSING, Connector 6P LX40/LX50Short Coil FILTER, Line Fluorescent Indicator TubeTUBE, Fluorescent Indicator Short Jumper SelectorTransistor 2SC2712Y-TE85L TransistorTransistor PT380F3 Transistor 2SC1815GR-TPE2Metal Oxide SWITCH, Tact ·PLAY SWITCH, Rotary ModeSWITCH, Tact 0REW SWITCH, Tact PpauseRef. No Description Remarks Ref. No Published by Quality Assurance Dept Sony Corporation
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