
3-6
SECTION3 ELECTRICAL
ELECTRICAL TROUBLESHOOTING GUIDE
3. Y/C CIRCUIT
(1) No Video in EE Mode
Does the Video signal appear
at the IC301 Pin29?
NO
NO
NO
Check the IC3G1 Pin14
and Q3G1 emitter.
Check the path of the signal between
the IC301 Pin29 and IC501 Pin49.
Is there 9V on the plus
terminal of the C381?
No Video in EE Mode
Does the Video signal appear at the
IC3G1 Pin9?
YES
Does the Video signal appear
at the IC301 Pin38?
YES
Check the Video input Jack &
jack Board connection.
YES
Is I
2
C BUS signal applied to the
IC301 Pin 23, 24?
Check C316.(AGC)
Replace the Q380.
Check the System Circuit. (Refer to
‘SYSTEM I
2
C BUS Trouble Shooting’)
NO
Does the Video signal appear
at the IC501 Pin 47?
YES
Does the Video signal appear at
the Emitter terminal of the Q380?
YES
NO
NO
NO
YES
Replace the IC301.
YES
Check the 9V Line.
(Power Circuit)
NO
Is 5V applied to the
IC301 Pin16, 40, 55, 58, 75, 87?
YES
Check the 5VA Line.
(Power Circuit)
NO
Summary of Contents for TL-AT130M
Page 23: ...3 14 3 13 SECTION3 ELECTRICAL BLOCK CIRCUIT DIAGRAMS 1 OVERALL WIRING DIAGRAM ...
Page 24: ...3 16 3 15 SECTION3 ELECTRICAL BLOCK CIRCUIT DIAGRAMS 2 POWER BLOCK DIAGRAM ...
Page 25: ...3 18 3 17 SECTION3 ELECTRICAL BLOCK CIRCUIT DIAGRAMS 3 POWER CLRCUIT DIAGRAM ...
Page 26: ...3 19 SECTION3 ELECTRICAL BLOCK CIRCUIT DIAGRAMS 4 AUDIO BLOCK DIAGRAM ...
Page 27: ...3 20 SECTION3 ELECTRICAL BLOCK CIRCUIT DIAGRAMS 5 Y C BLOCK DIAGRAM ...
Page 28: ...3 22 3 21 SECTION3 ELECTRICAL BLOCK CIRCUIT DIAGRAMS 6 A V CIRCUIT DIAGRAM ...
Page 29: ...3 23 SECTION3 ELECTRICAL BLOCK CIRCUIT DIAGRAMS ...
Page 30: ...3 25 3 24 SECTION3 ELECTRICAL BLOCK CIRCUIT DIAGRAMS 7 SYSTEM BLOCK DIAGRAM ...
Page 31: ...3 26 SECTION3 ELECTRICAL BLOCK CIRCUIT DIAGRAMS ...
Page 32: ...3 28 3 27 SECTION3 ELECTRICAL BLOCK CIRCUIT DIAGRAMS 8 SYSTEM CLRCUIT DIAGRAM ...
Page 33: ...3 30 3 29 SECTION3 ELECTRICAL BLOCK CIRCUIT DIAGRAMS 9 JACK CLRCUIT DIAGRAM ...
Page 34: ...3 32 3 31 SECTION3 ELECTRICAL BLOCK CIRCUIT DIAGRAMS 10 KEY BOARD CLRCUIT DIAGRAM ...
Page 35: ...3 34 3 33 SECTION3 ELECTRICAL PRINTED CIRCUIT DIAGRAMS 1 MAIN P C BOARD ...