Troubleshooting Guide - Kortek KT-2914F Service Manual

5. TROUBLESHOOTING GUIDE

5-1. Troubleshooting Guide.
NOTES ;
1. If picture does not appear, fully rotate the brightness and contrast controls
clockwise.
2. Check the following circuits.
No raster appear : power circuit. Horizontal output circuit.
High voltage develops but no raster appears : Video output circuit.
High voltage does not develop : Horizontal output circuit.
5-2-1. No Raster, No Video
No Power
Measure +80V output between
cathode of D110 and Ground.
Does appear 80V DC?
Check and replace
F101,IC103
5-2-2 S-Correction failure.
Check S1,S2,S3 signals refer to
S-correction table on the schematic
S1,S2,S3 signal are right
at each frequency block
Check and replace
Q704,707,709,703,706,708
High voltage control circuit and output circuit.
YES
NO
YES
Check the other secondary
outputs(+250V,+130V,+80V,+12V,
-12V,+12V,+6.3V ,5V Lines)
Does each output appear?
Check and replace
D104,D105,D106
D108,IC103,IC101
C/S TABLE
S1 S2 S3
1 ~17K L
2 17~28K L
3 29~34K L
4 34~40K H
NO
Check and replace
Check Video and
Horizontal circuits
L L
L H
IC103 1pin
H H
H H