IMPORTANT: WHILE
WORKING WITH TV OR ANY CIRCUIT WITH HIGH VOLTAGES IT IS WISE TO USE AN
ISOLATION TRANSFORMER FOR YOUR SAFETY! (I need to buy one soon!!)
TYPE: KS1A14E4
MODEL: CZ-14E4V
SYMPTOM: TV dead. i.e., no sign of power on switching ON, nothing happens :(
FAULT DIAGNOSIS:
- the problem seems to be in the smps section
- checked the voltage at the main filter cap which was around 260V (this ensures ckt till this point is fine)
- the main dc supply (260V approx) was reaching the drain pin of the power regulator ic (KA5Q0765R), but the voltage at the Vcc pin was pulsating
- this could mean that the ic is gone and needs replacement but i was not sure of it, so kept searching for some more faults
- on checking the secondary side of the smps, found a diode shorted
- RU20JGF, 600V, 2A fast switching plastic rectifier diode on the B+ line
- replaced the diode and resoldered the dry joints
- turned the tv ON and immediately heard a blast, PICTURE OK but this time NO SOUND :(
to be contd..
TYPE: KS1A14E4
MODEL: CZ-14E4V
SYMPTOM: TV dead. i.e., no sign of power on switching ON, nothing happens :(
FAULT DIAGNOSIS:
- the problem seems to be in the smps section
- checked the voltage at the main filter cap which was around 260V (this ensures ckt till this point is fine)
- the main dc supply (260V approx) was reaching the drain pin of the power regulator ic (KA5Q0765R), but the voltage at the Vcc pin was pulsating
- this could mean that the ic is gone and needs replacement but i was not sure of it, so kept searching for some more faults
- on checking the secondary side of the smps, found a diode shorted
- RU20JGF, 600V, 2A fast switching plastic rectifier diode on the B+ line
- replaced the diode and resoldered the dry joints
- turned the tv ON and immediately heard a blast, PICTURE OK but this time NO SOUND :(
to be contd..
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