No Raster (Hv./Def Protection Circuit Failure) - Tatung OMNISCAN SERIES Service Manual

6.2 NO RASTER (HV./DEF PROTECTION CIRCUIT FAILURE)
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SET THE INPUT HORIZONTAL FREQUENCY AT 64KHZ
CHECK HV./DEF - - - - - - - - - - - > THE HIGH VOLTAGE PROTECTION CIRCUIT
...---- PROTECTION MAKES AN AUDIBLE NOISE DURING
NO
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OPERATION
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YES
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CHECK OUTPUT
-------------->
PULSE
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OK
CONNECT 2700PF /1600V CAPACITOR
AT PINS 1, 4 OF T603
CONNECT 2700PF/1600V CAPACITOR
AT PINS 2,5 OF T401
TO DECREASE THE OUTPUT PULSE
RASTER
---------------------->
CHECK HV & DEF CIRCUIT
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NO
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HV. PROTECTION
SEE ITEM 6.4/6.5
YES
AUDIBLE NOISE--------------> HV & DEF ----------) D618, R641, R640, C631
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PROTECTION 0414, 0413, R432, C418
: CIRCUIT FAILURE
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NO
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L ____ >
CHECK HV & DEF CIRCUIT
SEE ITEM 6.4/6.5
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END
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6-2
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