Electrical Adjustment; Precaution; Required Test Equipment; Required Adju - JVC HR-A630MS Service Manual

SECTION 3
ELECTRICAL ADJUSTMENT
3.1. PRECAUTION
Electrical adjustment are required after replacing circuit
components and certain mechanical pans. |1 is important to
perform these adjustments only after all repairs and replace-
ments have been completed. Aiso do not attempt these ad-
justments unless the proper equipments is available.
3.1.1 Required test equipment
@ Colour television or monitor
@ Oscilloscope: wide-band, dual-trace, triggered delayed
sweep
@ Frequency counter
@ Digital voltmeter
© Signal generator: RF/F sweep/maker
© Signal generator: PAL/SECAM colour bar, stairstep
@ Recording tape
@® Numeric-key remote controlier(provided)
3.1.2 Required adjustment tools
Alignment tape Presetting unit
(SP stairstep) PTU94008
MHPE
3.1.3. Colour bar signal,colour bar pattern
@ PAL colour bar signal
White(100%)
White(75%) & |
2
0.7V Burst
Vv i
| ~Tosv
0.3V
ae es V U
nee V(R-Y)
U(B-Y)
Fig.3-1-1 PAL colour bar signal waveform
@ PAL colour bar pattern
(75%)
Fig.3-1-2 PAL colour bar pattern
@ SECAM colour bar signal waveform
Carrier(4.406 MHz) = Carrier(4.250 MHz) _—_ Horizontal sync
R-Y colour BAR
Fig.3-1-3 SEACM colour bar signal waveform
@ SECAM colour bar pattern
Fig.3-1-4 SECAM colour bar pattern
3.2 SERVO CIRCUIT
Notes: - Uniess otherwise specified,all measurement
point and adjustment parts are located on the
MAIN BOARD.
* Set VCR to the mode A by remote controller.
+ Use only buttons "O", depressing other buttons
during adjustment may cause adjustment er-
rors.
3.2.1 PB switching point
Signal * Alignment tape [MHPE],Stairstep
Mode °PB ee | =
* Oscilloscope
Equipment
|
Measurement point Y eorat 1- pin 19 (VIDEO OUT)
{TERMINAL BOARD]
| eae
Trigger slope (-) © TP111(ORUM FF) , [PRE/REC BOARD}
Adjustment tool Presetting unit [PTU94008}
2 ames
°6.5 2 05H
Specification
(1) Connect an oscilloscope to J1411- pn 19 (VIDEO OUT
and external trigger from TP111 (negative slope).
(2) Playback the stairstep signal of the alignment tape.
(3) Press the "O" button of the presetting unit.
(4) The adjustment is performed automatically.
Once the adjustment is performed, the VCR will go into
the STOP mode.
Fig.3-2-1 Presetting unit
Switching point V. sync
=.
—— 65:10.5H '
V. rate
Fig.3-2-2 PB switching point
3.2.2 Siow tracking preset
¢ Tuner or colour bar
Mode
—
eSP/LP, REC —+ PB(ISLOW
Equipment ¢TV-Monitor
*Presetting unit [PTU94008}
Adjustment tool
Specification © Minimum noise
Note : Set VCR to the mode A by remote controller.
Use only buttons "B" and "C*, depressing other
buttons during adjustment may cause adjustment
errors.
(1) Record a colour bar signal in the SP mode.
(2) Playback recorded signal on the FWD slow mode.
(4) Depress the STOP button. ;
(5) Confirm that the bar noise is not visible on the TV moni-
tor in the slow mode.
(6) Repeat steps (2) to (5) in the LP mode.
Fig.3-2-3 Presetting unit
3-2