Adjustment Of Vf Circuit; Adjustment Of Vf_Com Amplitude (Main Pwb) - Sharp VL-Z400H-T Service Manual

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)
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
R782
R732
R730
TL1206
R708
R710
TL1207
R706
R707
TL8803
R740
C708 R736 R729 R759 C710 R735 C733 R755
R1801 C717
R738 R737 R763 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
R1828
L1803
TL1812
C1815 R1816
C1406
C1813 C1812
TL1451
R1419
L1802
C1407
R1402
R1422
TL6807
R1414
R1406 C1416 R1405 C1418
TL1452
Q1404
R6808
R1423
R6807
TL1808
R6839 C6827 R6832
R6837
R6840 R6833
TL1809
C4418
R4415
TL1810
C4417
Q1405
C1419
C4424 C220 C219
R1421
R246 C4422
C1410 R219
C1408 C1409
TL1450
TL206 TL207 TL205
4C1 4C4 582 58C
68 B0 48 90
voltage to the adjustment rating.
C727 C1940 TL916
C715 R726 R727 C714 R701
TL920 C1960
R1900
C1911
X701
C962
C978
Q1912
Q905
D916
TL903
D960
C929
R1926
R8807
TL904
R8804
C8806
Q8800
TL8801
Q8801
R8803
C8807
C8810
IC8800
R8867
D6800
R8868
TL7824
R6805 C6804
R8866
L6800
R4403
R6810
TL7805 C4442
TL7802 TL7801 FB4402
C4421 R6800 TL7804
TL4470 TL204
L7810
C7821
C7810 R7811
R7836
C211
C208
TL203
C207
TL3707
IC4401
C205 TL4440
Address VCR ADJ 32
31
VL-Z400S-T/H-T
VL-Z500S-S/H-S/E-T/E-S
L931
TL8801(VF_COM)
VF_COM
L907 L901
R8806
TL907 C8803 TL911
C934
Q1901
TL910
C3727
C1901
C939
TL921
R8814 R8828
C3708
R8827 TL8802 C3710
TL8806(VF_VB)
TL908
VF_WB
TL8809
IC3702
TL8804(VF_VG)
VF_WB
TL8806
C8824
TL8804 TL8805
C3702
C3704 R3705 R3717 C3705 C3712 C3709
TL8805(VF_VR)
VF_WB