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6-1

For the mechanical adjustments, please refer to the
“VHS MECHANICAL ADJUSTMENT MANUAL
(S MECHANISM)” (9-921-647-11).

See the adjusting part location diagram from on page 6-6
for the adjustment.

The measuring instruments used for this alignment include:
1)

Monitor TV

2)

Oscilloscope, dual-trace, bandwidth of 30 MHz or more, with
delay mode (A probe 10:1 should be used unless otherwise
specified.)

3)

Frequency counter

4)

NTSC Pattern generator

5)

PAL Pattern generator

6)

Digital voltmeter

7)

Audio generator

8)

Audio level meter

9)

Audio attenuator

10) Alignment tapes

KRV-51P (PAL)

Part No. : 8-192-605-36

KRV-51N2 (NTSC) Part No. : 8-192-605-32

Unless otherwise specified, connect and adjust the measuring
instruments as shown in the following diagram.

Fig. 6-2-1

In this adjustment, PAL or NTSC pattern generator is connected
with LINE input terminal.  When check to tuner, connected AERIAL
terminal.  Check that the synchronizing signal of the Y signal has
an amplitude of approximately 0.7 V and that the burst signal has
an amplitude of approximately 0.3 V and its waveform is flat. And
check that the level ratio of burst signal to “red” signal is 0.30 :
0.66. The video signal (color bar) used for electrical aligning this
unit is shown in Fig. 6-2-2.

Fig. 6-2-2 Color Bar Signals of Pattern Generator

• Contents of KRV-51N2/51P

Red

Horizontal sync signal

Burst signal
(It must be flat.)

Approx. 
0.3 V

White (Approx. 75%)

Approx. 0.3 V

Approx. 0.7 V

VIDEO LINE IN

VIDEO LINE OUT

Video output

(75

Ω

)

Pattern generator

VCR

Monitor TV

White (100%)

About 0.7 V

About 
0.3 V

Horizontal sync signal

Red

Burst signal
(It must be flat.)

About 
0.3 V

1

2

3

4

Mode

SP

LP

Period

7 minutes

3 minutes

7 minutes

3 minutes

Video signal

Color bar

Monoscope

Color bar

Monoscope

Audio signal

Hi-Fi

400Hz

(L/R)

Normal

400Hz

6-2

Video input: LINE IN

Input signal: 1 Vp-p, 75 ohms, unbalanced,
sync negative

Video output: LINE OUT

Output signal: 1 Vp-p, 75 ohms, unbalanced,
sync negative

Audio input: LINE IN

Input level: –7.5 dBs
(0 dBs= 0.775 Vrms)
Input impedance: more than 47 kilohms

Audio output:LINE OUT

Standard level: –7.5 dBs at load impedance 47
kilohms
Output impedance: less than 10 kilohms

The adjustments should be performed in the following sequence.

Mode

E-E

Measuring Instrument

Digital voltmeter

+12 V Check

Measurement point

CN201 pin 

!º

Specified value

11.5 –13.0 V

+5 V Check

MP

CN206 pin 

!£

SV

5.0 –5.6 V

+9 V Check

MP

Emitter of Q961

SV

8.5 –10.0 V

MTR12 V Check

Measurement point

CN204 pin 

4

Specified value

11.5 –13.0 V

[Check Method]
1)

Each of these supply voltages must meet its specified value.

Power Supply Check

Servo/Video System Adjustments

Audio System Adjustments

6-3

[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: Video LINE OUT

(75 

Ω

 terminated)

(AF switching position)

CH2: CN101 pin 

3 (V SWP)

Measuring instrument

Oscilloscope

Adjusting element

RV202

Specified value

6.5 ± 1 H (413 ± 60 

µσεχ): ΝΤΣΧ

6.5 ± 1 H (416 ± 32 

µ

sec): PAL

[Adjustment Method]
1)

Playback the alignment tape.

2)

Short-circuit between pins 

1 and 2 of CN210.

3)

Check that “RF” is indicated on FL display.

4)

Check that switching position is 6.5 ± 1 H.

5)

If not meet the specified value, turn RV202 and repeat steps 1)
to 3).

Fig. 6-2-3

CN202 pin 

3

6.5 

±

 1 H

(413 

±

 60 

µ

sec): NTSC

(416 

±

 32 

µ

sec): PAL

Approx. 
1Vp-p

CH1

CH2

Approx. 
5Vp-p

CH1

CH2

V

Enlargement

Vertical sync. signal

• Adjust both L ch and R ch.
[Connecting Instruments]

Fig. 6-2-4

• Perform the adjustment setting the switch on the following

positions.

• AUDIO MONITOR ..................................................... STEREO

[Adjustment Method]
1.

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

2.

E-E output level check

3.

“Recording Bias Adjustment”

Audio line OUTPUT L/R

Audio line INPUT L/R

Audio oscillator

Attenuator

600 

Ω

Audio level meter 
or distortion meter

47 k

Ω

VTR

6-4

• Make adjustment in the SP mode unless otherwise specified.  Use

a normal VHS cassette for an adjustment tape.

• Set AUDIO MONITOR to normal.

Refer to the VHS mechanical adjustment manual 

 (S

MECHANISM) (9-921-647-11).

[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

CJ461 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 CJ461 L/R.

2)

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

[Adjustment purpose]
Confirm that the frequency characteristic is within the specification.

Mode

REC and PB (SP mode)

Signal

400 Hz, –27.5 dBs
7 kHz, –27.5 dBs

Measurement point

Audio output terminal

Measuring instrument

Audio level meter

Specified value

0 ± 3 dB

Tape path adjustment must have been completed.

[Confirmation Method]
1)

Supply a signal of 400 Hz, –27.5 dBs to both L and R channels
of Audio Line Input.

2)

Connect the audio level meter to the Audio Line Output.

3)

Adjust the attenuator so that the audio level meter will indicate
–27.5 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.

[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 

3 of CN101

CH2: Pin 

1 of CN101

Measuring instrument

Oscilloscope

Adjusting element

RV201

Specified value

Fig. 6-2-5

[Adjustment Method]
1)

Playback the alignment tape.

2)

Short-circuit between pins 

1 and 2 of CN210.

3)

Adjust RV201 to minimize a chipped portion.  At this time,
confirm that a noisy sound is not heard.

Fig. 6-2-5

CH2
RF SWP

CH1
REC AFM

Should be minimized

RF signal dropout

NG

OK