ViewSonic VT2730-1M Service Manual page 45

TTV receiving test:
TV SIGNAL TEST ITEM
CENTRALISM TRANSMITTING SIGNAL CHECK CONTENT
FREQUENCY
CHANNEL
ORDER
CHANNEL 2
CHANNEL 6
CHANNEL 7
CHANNEL 13
CHANNEL 14
CHANNEL 36
CHANNEL 69
TV TEST METHOD
A.CHANNEL2 Examines sound by ear, whether the sound does have mechanical resonation and
the electrical unusual sound, and image to sound disturbance.
B.CHANNEL6: Check sound and picture.
C.CHANNEL7: Examines whether the sound does receive the image disturbance, Judgment basis:
Whether there is unusual sound, input signal LEVEL<=36dBu,and STEREO SENSITIVITY is
normal.
D.CHANNEL13: Under main/sub/main-sub mode, check sub function.
E.CHANNEL14: Examines whether the sound does receive the image disturbance, Judgment basis:
Whether there is unusual sound.
F. CHANNEL 36:Check T1 of close-caption. Input signal level<=45dBu.
G.CHANNEL 69: Adjustment attenuator, If the critical point of the change of the image signal to
noise ratio is under LEVEL<=60dBu, regards as normally.
PRODUCTS OUTPUT CHECK ITEM.
The same as " CENTRALISM TRANSMITTING SIGNAL CHECK CONTENT"
saturation TEST, inputs the TV signal, the input signal LEVEL establishment most greatly is
90dBu,check whether CONTRAST of the image is normal; Whether appears the disturbance
phenomenon.
C.AFT CHECK,
(1) The frequency of the input TV signal is 211.25MHz (CH13), after confirmed the TV set
receives this signal, closure radio station; Then set frequency of the TV signal generator to be
212.25MHz, turn on the TV set and check whether the TV set receives the signal of CH13.
(2). The frequency of the input TV signal is 211.25MHz (CH13), after confirmed the TV set
receives this signal, closure radio station; Then set frequency of the TV signal generator to be
212.00MHz, turn on the TV set and check whether the TV set receives the signal of CH13.
(3). After all of FUNCTION TEST completed, we must erase all saved changes again and restore
the factory defaults.
DTV TEST ITEM
CHANNEL FREQUENCY
14
36
69
ViewSonic Corporation
(MHz)
PATTERN
55.25 MONO SCOPE
83.25 COLOR BAR
175.25 Full White (100
IRE)
211.25 STAIR
471.25 MULTIBURST
603.25 MULTIBURST
801.25 MONO SCOPE
SOUND
471.25MHz Y
603.25MHz Y
801.25MHz Y
SET CONTENT
SOUND P/S(dB)
SWEEP TONE -10
400Hz -10
STEREO -10
DUAL -10
MONO -16
MONO -10
MONO(1KHz) -10
dB PETTEN
Dynamic
50
picture
50 Color bar
Dynamic
75
picture
44
Confidential - Do Not Copy
CHECK
CONTENT
ELECTRIC
ABNORMITY
SOUND
SOUND ,PICTURE
STERO FUNCTION
SUB FUNCTION
IMAGE AND
SOUND DISTURB
TEST Close-caption T1
FUNCTION
NOISE LIMMITTED
SENSITIVITY
CHECK CONTENT
Picture
Color
Sound and Picture
VT2730-1M