Service manual

30
VL-MC500U/K
1. DAC full-scale adjustment
Test point TL7824(G OUT)
Address VCR ADJ 5DF(G)
Mode VCR AV input
Procedure 1) Set the data of the addresses 582/585/59A/5E1 to FF/80/77/00, respectively. (At this time, the LCD is not
displayed.)
2) Set the data of the addresses 595/5D0/5D3 to 00/80/48, respectively.
3) Connect a digital voltmeter to TL7824(G_OUT) to measure the DC voltage.
* The voltage value at this time is regarded as (DA_VG).
4) Set the data of the addresses 595/5D0 to 80/00, respectively.
5) Adjust the DC voltage to the adjustment standard value at the address 5DF.
6) Preset the same data as the address 5DF to 5DE/5E0.
7) Restore the data of the addresses 582/585/595/59A/5D0/5D3/5E1. (Initial values: 40/C5/28/7F/28/40/71)
Adjustment DA_VG+0.55V ± 10mV
rating
Examples • During IC705 replacement. • During VIO ENG (IC4401) replacement.
ADJUSTING THE LCD CIRCUIT
* To make this adjustment, set the backlight switch to the "NORMAL" position.
(Wiring board diagram: Main Side A)
Adjustment procedure and connecting same as the VCR section.
2. COMMON PULSE adjustment
Test point TL2801(C OUT) Address VCR ADJ 32(C)
Mode VCR AV input
Procedure 1) Connect TL2800 to GND.
2) With VCR ADJ 32, adjust the output voltage of TL2801 and the DC voltage value of the digital voltmeter to the
specified adjustment values.
Adjustment 7.05V ± 50mV
rating
Examples • During IC705 replacement.
(Wiring board diagram: Main Side B)
3. COM-BIAS adjustment
Test point LCD panel display surface Address VCR ADJ 33
Mode VCR AV input
Procedure 1) Input the white 100% signal to AV input.
2) Set up the illuminance meter (TOPCON IM-3) on the LCD panel surface. (The outside light must not enter.)
3) Minimize the ripple of the output waveform of the illuminance meter.
Adjustment Minimum
rating
Remark Make this adjustment after 5-minute or longer aging.
Examples • During LCD Panel replacement. • During IC705 replacement.
Response time : 0.6sec
0
4
3
301
R407
R463
C420
D472
C425
C473
R477
D471
C2826
L471
R478
C2827
C472
R2856
C474
L2803
C419
C2822
C2828
R2840
C2823
L2802
R418
X401
C2806
C418
R2805
R2804
TL4429
R2801
TL418
R2811
C2802
TL2824
D2801
R2851
C2800
R432
C475
C421
TL2825
R2812
R2815 R2813
R2852
TL2826
C476
R431
C410
R2814
Q2800
TL2800
R2853
D2800
FB456
SC2801
R2802
R2803
C430
TL2801
C2801 R2818
D2802
R2821
R2807
C2807
R2822
IC40
7
IC2803
C2803
R2819
Q2801
C2824
R2820
TL2836
R2829
C2815
C463
Q2802
TL2835
R2830
R2825
C
C2825
C2816
C2814
R2824
R280
C2813
C2812
R2823
C2808
IC2800
C2805
R2806
C2811
C2810
L280
0
C2809 C2804
TL2801(C OUT)
COMMON PULSE
TL2800
COMMON PULSE
C7802
L7800
C7826
R7836
R7840
R7835
R7837
C7827
C208
5
R7831
Q7800
C1431
C7800
C7830
R7824
R7823
R7828
R7838
R7825
C7804
C7825C7819R7839
C7820
C7828
C7822R7809
C7824
C7829
IC7802
IC7801
L1431
R7810R7834
C1441
R7830
C1440
R7833
C7821
D7810
R7832
IC1431
R7827
R254
C1439
TL7824
TL7825
C1438
R7812C7812
R7820
R7821
R253
TL7820
TL1431
R7829
C7805
C7801
Q1432
Q1431
R251
C7823
R1432
C1432
C1436
R7826
C7806
R7822
L7810
R1440R1441C1437
R252
R1442
C7803
C7808
C7809
C7807
TL7823
R1439
C205
C7810R7811R7819
C7813
C1409
Q1434
R
1
R1431
R1438
C204
TL234 TL4439
C4481
R4495
IC1401
C4482
R4472
C4485
R7800
C7814
TL4437
R4471
R4486
C4428
C7816
R4407
4
414
TL4440
C7815
R4485
C1410
C4426
C7817
C1408
Q4481
R4401
C4427
R4454
IC4401
C7818
C1413
D4452
R4456
C4454
L1406
Q1402
R1405
R4408
TL4428
L4451
Q4483
TL4405
R1422
TL4426
R4489
R4488
Q1404
C1402
X4451
C4419
Q
C4416
TL7824(G OUT)
DAC full-scale