Picture Projection Test; Picture Projection; Checking The Operation Of Bach Section; Checking The Voltage - Sony Multiscan GDM-2036S Service Manual

GDM-2036S
6-2. PICTURE PROJECTION TEST
6-2-1. Picture projection
1) Make sure that the power switch for the unit is set to OFF
and supply power from an isolated-type variac.
2) Adjust the AC input voltage to the rated value and turn
the power on.
3) Supply MODE 7 signal to the set. (Recommended signal
is the black cross-hatch on the white flat field pattern).
4) Adjust the SCREEN (G2) VR so that the raster become
starting to be visible.
5) Adjust the H. FOCUS (G2) and V. FOCUS (FI) variable
resistors in the focus pack and optimize the overall screen
focus. If the center vertical static misconvergence is too
large (
±
O.lmm or greater), adjust the six-pole magnet.
(See 6-3-6.)
6) Verify that the image is not moving.
7) If the image is moving left to right or right to left, input
Mode 1 signal first and then switch off the SG sync signal
or for internal synchronization remove the G input, then
turn the H. FREQ control on the N board to stop the
image.
8) Reconnect the sync signal and supply some other scan
mode signal and double check 6).
6-2-2. Checking the operation of each section
1) Check that the green Power On indicator lamp lights up,
when the power for the set is switched on.
2) Operate the following controls and check that their cir-
cuits are functioning.
<User's Controls> ...... see P. 10 to know how it works.
<D
I CONTRAST I
®
I BRIGHTNESS I
@IH.SIZEI
@IH.CENTI
®Iv. SIZEI
®IV.CENTI
(7) Iv. STATI·
®IH.STATI
<Internal Controls>
®
SCREEN(G2)······ changes the overall brightness
for the screen.
@) V. FOCUS(Fl) ..... changes the focus in the ver-
tical direction.
@ H. FOCUS(F2) ..... changes the focus in the hori-
zontal direction.
@
R. DRV, G. DRV, and B. DRV VRs
(A board) . change the peak brightness for their re-
spective colors.
@ R BKG, G. BKG, and B. BKG VRs
(A board) . change the dark level brightness for their
respective colors.
3) Checking the connection for R. G. B
Turn the R, G and B switches for the signal generator ON
and OFF to check if each switch renders correct R, g and
B color reproduction.
6-2-3. Checking the voltage
check that the following voltage are present on each board.
1) +B : 145
±
3V (G board CNG6
<D
pin)
2) +lOV: 21
±
2V (G board CNG6 ® pin)
3) - lOV : - 21
±
2V (G board CNG6
®
pin)
4) +12 : 12
±
O.6V (G board CNG6@pin)
5) - 12 : - 12
±
0.6V (G board CNG6 ® pin)
6) +65 : 66
±
3V
(G board CNG5 (7) pin)
7) The voltage between TP505 and GND of D3 board is
within the 9.00
±
0.05 V range. When the voltage is out
of the specified range, turn RV501 to adjust it to within
the required range.
6-3. ADJUSTMENT
6-3-1. White balance rough adjustment
- Component side -
B. DRV G. DRV R. DRV B. BKG G. BKG R. BKG
0 0 0 0 0 0
RV301 RV201 RV101 RV406 RV405 RV404
o
1
SW401 l ______ ---'
Fig. 6-3-1 A board
1) Setting the video signal level
<D
Input a full-white signal (a flat field signal in which
the video level is 0.714Vp-p for R, G and B).
®
Set to the following points.
<A board>
RV404(R. BKG) ............................. Minimum
RV 405(G. BKG) ............................. Minimum
RV406(B. BKG) ............................. Minimum
RVI01(R. DRV) ............................. Minimum
RVlOl(G. DRV) '" .......................... Minimum
RV301(B. DRV) ............................. Minimum
Front panel
I
CONTRAST
I
control ........................ Maximum
-90-