Sony TRINITRON GDM-1601 Service Manual page 27

1. PICTURE PROJECTION TEST
1·1. Picture Projection
I) Connect power from an isolated-type variac after
checking that the power switch of the set is turned
off.
2) Adjust the AC input to the rated voltage.
3) Supply signals to the set.
4) Adjust SCREEN VR so that the raster brightness
is at an appropriate level.
S) Check that the picture is nqt rolling.
6) Rotate RV207 (H FREQ) on the 0 board to lock
the picture, if there is slipping.
1·2. Checking the Operation of Individual Sections
I)
Check that the POWER lamp (green) lights when
the POWER switch on the set is turned on.
2) Apply input signals.
3) Rotate the following VR's and check that the circuits
are functioning.
(1)
CaNT (contrast) VR
(2) V. CENT VR
(3) V. STAT VR
(4) H. STAT VR
(S) SCREEN VR
(6) FOCUS VR
(7) R DRV, G DRV, B DRV VR's (on the A board)
(8)
G BKG, B BKG VR's (on the A board)
4) Checking Direction of Rotation of Contrast YR.
Check that the contrast increases when the contrast
VR is rotated clockwise and that it decreases when
rotated counterclockwise.
After checking, rotae the contrast VR clockwise fully
and make the contrast maximum.
S) Checking R, G, and B connection.
Alternately switch on and off the R, G, and B
switches on the signal generator and check for cor-
respondence between the three colors R, G, and B.
1·3. Checking Voltage of Individual Sections
Checking that the following voltages are present on each
board.
I) +B Voltage
2) +12 V output
3) -12 V output
14S:~
V (GDM-1602:
120:~
V)
(D-I pin I -
pin
3 GND)
12.0 ±0.3 V (0-1 pin
® -
pin
CD
GND)
-12.0 ±0.6 V (0-1 pin
® -
pin
CD
GND)
4) The voltage between TP304 on the 0 board and GND
is 9.00 ±O.OS V.
Readjust by rotating RV30 I if the standard is not
met.
S) +B2 Voltage S9.0 ±3 V (0-1 pin
0 -
GND)
4-1
2. ADJUSTMENT
2-1. White Balance Coarse Adjustment
o
D D
D D o
RV403
RV402
RV401
RV405 RV404
51
Fig. 2-1-1 A board
l) Adjustment of video signal voltage
(I) Input the full white signal
Set to the following points:
(2) A board RV404 (G-BKG) Min
RV40S (B-BKG) . . . . Min
RV401 (R-DRV) Min
RV402 (G-DRV) . . . . . Min
RV403 (B-DRV) . . . . . Min
Front Panel CaNT VR . . . . . . . Max
(3) Connect the oscilloscope probe to TP2 (KR) on
the C board.
(4) Vary RV401 on the A board and adjust the video
level to 40 Vp-p. (See Fig. 2-1-2.)
(S) Connect the oscilloscope probe to TPI (GIR) on
the C board.
Pedestal
Level
Pedestal
~.L
Video Level
. . L . . - - - - - - - - - - - - - G N D level
Video Level +35.0 - 40.0 [Vp-p]
Fig. 2-1-2