14Gt15 - Sharp 14GT15 Service Manual

14GT15

14GT20
No. Adjusting point
1 SUB-TINT (I 2 C
BUS CON-
TROL)
PROTECTOR OPERATION CHECKING
No. Adjusting point
1 BEAM PRO-
TECTOR
2 H, V PROTEC-
TOR
3 Other
protectors
A/V INPUT AND OUTPUT CHECKING
No. Adjusting point
1 VIDEO AND
AUDIO
OUTPUT
CHECK
2 VIDEO AND
AUDIO INPUT
CHECK
NTSC CHROMA ADJUSTMENT
Adjusting procedure/conditions
1. Receive the "NTSC3.58 Colour Bar" signal
through AV in.
2. Connect the oscilloscope to TP853 (Pin (5) of
P882) BLUE-OUT.
» Range
: 100mV/div. (AC)(Use Probe 10:1)
» Sweep time : 10 sec/div.
3. Call the "SUB-TINT" mode in service mode. Ad-
just the "SUB-TINT" bus data to obtain the wave-
form shown as Fig. 9.
4. Clear the SERVICE mode.
Adjusting procedure/conditions
1. Receive "Monoscope Pattern" signal.
2. Set CONTRAST MAX.
3. Set BRIGHT MAX.
4. During the Collector & Emitter of Q883/5/7 short,
make sure the protector ON and switch to standby
mode.
1. Receive "Monoscope Pattern" signal.
2. Connect output of Bias Box to D607 cathode
(R606 side).
3. Set voltage of Bias Box to 18V and make sure
the protector is not work.
4. Set voltage of Bias Box to 27V, and make sure
the protector is work.
1. Once finish rectified Electrolytic Capacitor short
testing in +B line, check all possible damaged
components on +B line.
(Use random selected set for inspection)
Adjusting procedure/conditions
1. Receive the "PAL Color Bar" signal (100% White
Color Bar, Sound 400 Hz 100% Mod.)
2. Terminate the Video output with a 75 ohm imped-
ance. Make sure the output is as specified (1.0
Vp-p 3 dB).
3. Terminate the Audio output with a 10k ohm im-
pedance. Make sure the output is as specified
(1.76 Vp-p 3 dB).
1. Using the TV/AV key on the remote controller,
make sure that the modes change in order of TV,
AV1, AV2 & TV again and the video & audio out-
put are according to the input terminal for each
mode.
(SAME LEVEL)
* Select one of Q883/5/7 to do
each short test.
16
Waveform and others
W Y Cy G Mg R B
Fig. 9
Waveform and others
Waveform and others