RCA SelectaVision VideoDisc SFT 100 Service Data page 25

CED-1
ELECTRICAL ADJUSTMENTS
(continued)
Video Level Adjust
1.
2.
3.
Use Test Disc 100 IRE white field signal (Segment Е).
Connect oscilloscope to TP 3401 (Figs. 4-9 & 5-2}.
Adjust R3202 (video level adjust) to produce 2.8V р-р
response.
Luminance Спаппе! Null Adjust
$
2.
3.
Use Test Disc color bar signal (Segment D).
Connect oscilloscope to ТР 3302 (Figs. 4-9 & 5-2).
Adjust R3328 for minimum chroma information (Fig. 4-5).
Fig. 4-5. — Waveforms Luminance Null Adjust
Chroma Channel Null Adjust
1:
2.
3.
Note:
Use Test Disc color bar signal (Segment О).
Connect oscilloscope to TP 3303 (Figs. 4-9 & 5-2).
Adjust R3329 for minimum p-p signal (Fig. 4-6).
Repeat Video Level Adjustment after completion of Lumi-
nance Channel Null and Ghroma Channel Null adjust-
ments.
Fig. 4-6. — Waveforms Chroma Null Adjust
Vertical Detail Level Adjust
1.
2.
Use Test Disc color bar signal (Segment D).
Connect oscilloscope to TP 3301 (Figs. 4-9 & 5-2).
Adjust R3317 so that the pulse level matches before and after
transition from vertical equalizing pulses to Vertical sync
pulses (Fig. 4-7).
Fig. 4-7. — Vertical Equalizing-Vertical Sync Pulses
Chroma Level Adjust
1. Use Test Disc color bar signal (Segment D).
2. Connect oscilioscope to TP 3409 (Figs. 4-9 & 5-2).
3. Adjust R3312 so that the p-p level of color reference burst and
sync tip to blanking are the same (Fig. 4-8).
m ЖО
nlia =
Fig. 4-8. — Color Burst/Sync Tip To Blanking Level
Defect Substitution Level Adjust
1. Use Test Disc 5 step linearity signal with 50 uS defect (Seg-
ment Н).
2. Connect Disc player to TV set. Locate defect (Line Мо. 130) by
rotating R3304 to one end of rotation (Figs. 4-9 & 5-2).
3. Adjust R3304 for proper substitution to make defect disappear
(adjust for best picture).
Armstretcher Gain Adjust
1. Connect player to TV.
2. Use Test Disc and play innermost band, 60 minute area (Seg-
ment 5).
3. Connect a 7500 ohm resistor between TP 3405 and TP 3411
(Figs. 4-9 & 5-2).
4. Rotate R3444 fully CCW. Adjust R3444 CW for no oscillation
(wiggles or horizontal color bands) in the picture.
5. Remove 7000 ohm resistor.