Service manual

36
VL-Z1U
The same adjusting procedure and connections as
described for the VCR section are used.
ADJUSTMENT OF LCD CIRCUIT
When making this adjustment, set the backlight switch to "Normal".
(Wiring board diagram: Main Side A)
(Wiring board diagram: LCD Side A)
1. Setteing of parameters (Main PWB)
* Preset the following data.
C818
R827
C821
C809
R825
R826
R807
R808
R806
8
12
TL845
C810
D800
C811
TL846
TL850
TL802
TL844
TL848
TL849
C817
TL847
SC802
TL803
TL846(LCD_VG)
LCD_contrast
2. Adjustment of VF_COM amplitude (Main PWB)
Measurement point TL8801(VF_COM) Address VCR ADJ 32
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
voltage to the adjustment rating.
Adjustment rating 3.75V ± 50mV
Examples · Replacement of IC705
3. Adjustment of VF_DAC full scale (Main PWB)
Measurement point TL7824(VF_G_OUT) Address VCR ADJ 59E
Procedure 1) Set the data values at addresses 587 (GRYLEV)/58C (γ PEAK)/5EB (TESTSW2) and 5E6 (OSDSW)
to FF/80/77 and 00, respectively. (The LED shows nothing.)
2) Set the data values at addresses 5A0 (CLAMP)/58D (PEDESTAL) and 5B9 (VCLK3 INV) to 00/80 and
48, respectively.
3) Connect the digital voltmeter to TL7824 (VF_G_OUT) and measure the DC voltage.
* The measured voltage is (DA_VF-G).
4) Set the data values at addresses 5A0 (CLAMP) and 58D (PEDESTAL) to 80 and 00, respectively.
5) At address 59E (VF_DAC_G), adjust the DC voltage to the adjustment rating.
6) Preset the data values at addresses 59D (VF_DAC_B) and 59F (VF_DAC_R) so that they are the
same as the data value at address 59E (VF_DAC_G).
7) Reset the data at addresses 587 (GRYLEV)/58C (γ PEAK)/58D (PEDESTAL)/5A0 (CLAMP)/5B9
(VCLK3 INV)/5E6 (OSDSW) and 5EB (TESTSW2) to their original values.
(Initial values: 40/C5/38/28/42/71 and 7F)
Adjustment rating DA_VF-G +0.23V ± 10mV
Examples · Replacement of IC705, IC4401
4. Adjustment of VF_WB (Main PWB)
Measurement point TL8804(VF_VG), TL8805(VF_VR), TL8806(VF_VB)
Address VCR ADJ 58E, 590
Procedure 1) Set the data values at addresses 587 (GRYLEV) and 5E6 (OSDSW) to 80 and 70, respectively.
2) Connect the oscilloscope to TL8804 (VF_VG) and TL8805 (VF_VR), and at address 58E (VF_WB-
R), adjust the amplitude to the adjustment rating.
3) Connect the oscilloscope to TL8804 (VF_VG) and TL8806 (VF_VB), and at address 590
(VF_WB_B), adjust the amplitude to the adjustment rating.
Adjustment rating 0mV ± 40mV, 0.1mV ± 40mV
Examples · Replacement of IC705, IC4401, IC8801
Address 046 047 048 049 099 0A5 0A6 0A7 0B5 406 407 408 409 427 435 40A 40B 41E
NTSC 1E 54 6B 76 01 40 7E 15 64 7F 7F 20 20 E7 24 70 70 00
PAL ————————69 ————E5 ————
Address 090 098 09A 0A3 0A4 097 40E 40F 42B 42D 42F
NTSC 7F — 40 91 96 C2 —————
PAL — 00 21 A2 A8 C9 14 14 03 09 06
2
SC1800
TL1431
C1438 R1442
C1810
C1439
L18
0
C1402
C1441 L1404
R1406
C1408
IC1431
C1416
C1407
C1410
R1405
IC1401
C1409
C1418
R1441
R1440
C1437
R1413
C1440
R6800 R1403 C1417
R1461
Q1405
C1436
R6810
R1404
R1421
C1419
R6813
R1462
Q1403
Q1434
4
406
R1424
C6800
R6812
C6807
R6804
R6803
R6802
R1423
R1414
R1438
R1439
Q6801
C
4481
R6805
C
R6807
C6801
C6802
R6817
TL6804
C6804
Q1404
R6809
TL6803
R6806
R6816
R6808
C4406
D6800
C6805
C6812
C6811
L6800
TL7819
TL6809
R6811
TL6802
TL6801
IC6801
TL6807
9
4 C6806 C6810
R6819 C6815 C6813 R6820 R6818 C6816
C6814
L7800
C7800
R7828 R7831
IC4401
R7827
R7826
R7829
IC7802
C
7
803
TL6807(G_OUT)
DAC full scale