Sharp VL-Z700S-T Service Manual page 31

3. Check of electromagnetic conversion circuit system (Auto check of playback envelope signal quality and error rate)
Mode VCR adjustment mode
Procedure 1) Insert a recordable tape and enter the VCR mode.
2) Press the "CONTINUE" → "TEST SEL" keys on the remote control for adjustment to enter the TEST mode.
("T-01" is displayed on the LCD.)
3) Select "T-0F" using the FF or REW key and press the PB key.
4) LP recording of the color bar/rewind/playback and playback envelope/error rate are inspected automatically.
5) The results are displayed about 50 seconds after the start.
(1) ENV NG: Playback envelope signal amplitude or balance between channels is lower than standard.
(2) SYNC NG: SYNC error rate is lower than standard.
(3) ECC NG: ECC error rate is lower than standard.
(4) CK-OK: No problem.
* If one of the error inspections 1 to 3 is NG, the result is displayed and the test ends at that point.
(Inspections following that are not executed.)
6) Turn off the main unit to exit.
Examples • When replacing the mechanism.
• When confirming a defect of the electromagnetic conversion system such as dirty video heads.
ADJUSTMENT OF VF CIRCUIT
(Wiring board diagram: Main Side A)
TL1207
TL7824(VF_G_OUT)
VF_DAC full scale
1. Setting data
Address 4AF 4B2
Data 77 30
2. Adjustment of VF_COM amplitude (Main PWB)
Measurement point TL8801(VF_COM)
Procedure 1) Set the data value at address 5EB (TESTSW2) to 77.
2) Connect the digital voltmeter to TL8801 (VF_COM). At address 32 (VF_DAC_C), adjust the DC
3.5V ± 50mV
Adjustment rating
Examples · Replacement of IC705
R708
R710
R706
R707
TL8803
R740
C708 R736 R729 R759 C710 C733 R755
R1801 C717
R738 R737 R763 R758 R735 R725 R720
C1801
R1822
R1821 R1820
C1811 R1827 R1800
R1823
C1804
R718 R1807
C1803
R771
C1810
C1802
R772
C1809
R1826
R747 R1804
R4402
C704
R1825
C1808 R1803
R4401
R1824
C1814
L1803 R1828
TL1812
C1815 R1816
C1406
C1813 C1812
TL1451
R1419
L1802
C1407
R1402
R1422
TL6807
R1414
R1406 C1416 R1405 C1418 TL1452
Q1404
TL6809
R1423
TL1808
TL7819
TL1809 C6811
C6800 R6805
TL1810
TL6803
Q1405
R6806
C1419
D6800
R1421 C6802
C6801
C1410
C1408 C1409
TL1450
R6807
C1437
R1439
4C1 4C4 582 58C
68 B0 48 90
voltage to the adjustment rating.
L931
C1911
X701
C962
C978
Q1912
Q905
D916
TL903
D960
C929
R1926
R8807 R8806
TL904
R8804
C8806
Q8800
TL8801
TL907 C8803
Q8801
R8803
C8807
C8810
IC8800
R8868 R8867
R8814 R8828
C8813 R8827 TL8802
TL7824
C7800
L7800 C4403
L7810
C7830
C7810 R7811
R7836
R7800
C3704 R3705
C4428
R4415
C4418
R4495 C4417
IC4401
C4426 TL4440
R4414
Address VCR ADJ 32
31
VL-Z700S-T
VL-Z800S-S/E-S/E-T/Z900H-S
VL-Z950S-S/E-A/E-S/E-T/E-W
TL8801(VF_COM)
VF_COM
L907 L901
TL911
C934
Q1901
TL910
C3727
C1901
C939
TL921
C3708
C3710
TL908
TL8806(VF_VB)
TL8809
VF_WB
IC3702
TL8804(VF_VG)
VF_WB
TL8806
C8824
TL8804 TL8805
C3702
R3717 C3705 C3712 C3709
TL8805(VF_VR)
VF_WB