#crt_tv_repair #how_repair_crt_tv #repair #how_to #no_power #chaina_bord
#tv_repair_at_home #crt_tv_repair_no_power
singer crt tv no power poblems it very simply fix In this case, troubleshooting should start from the AC input point itself. Check whether there is any break inside the AC chord, which prevents AC to come to the set. Check the continuity of the AC chord with a multimeter. We should check this starting from the AC plug; to the power supply circuit. If there is no AC voltage present at the main power supply regulator section circuit, check the On/OFF switch of the set for damage. If found faulty, replace it.
If AC is present at the supply point at the main power regulator section, then check for DC voltage across the +ve and -ve terminal of the main filter capacitor. If there is no DC voltage, check the main rectifier diodes, and the serial resistor [usually a wire wound fusible resistor (Surge protector)] connected to the bridge rectifier for open. If DC is there across the main filter capacitor, check its potential using a multimeter. If AC input voltage is 220VAC, the Rectified DC voltage should measure up to 300VDC. If not, replace the main bridge rectifier and/or the main filter capacitor used; will usually come up to the value of 100Mfd ~220Mfd 450V. When replacing electrolytic capacitors, make sure about its terminal polarity. If the polarity has been reversed by mistake, the capacitor will burst as soon as you switch on the set, after connecting it to AC mains, and will be dangerous too.
If the DC voltage is found OK, check the start voltage. For any TV using SMPS, this voltage is the most important to note, if the set does not switch ON. The main symptom will be that, you must have to switch the main power On/Off button several times, before the set to switch on. The start voltage is derived from the DC +ve voltage itself, by connecting one or two resistors or 270Koms or a single 470Koms. This voltage is used to trigger the SMPS oscillation. In most cases, this will be the reason for failure of the SMPS to start up. When checking these resistors, do not check it on circuit. Just desolder up one end of each resistor and measure for its resistance. If found abnormal, or open, replace it.
In this video I will teach you part by part how to make a china tv board correctly when you do not have a supply and watch the full video without skipping
#සැ:යු :- යම්කිසි අලුවැඩියා කටයුත්තකදී ඔබට ඇතිවන හදිසි අනතුරු හෝ භාන්ඩයට සිදුවන අලාභානි පිලිබදව මෙම නාලිකාව හෝ මා විසින් කිසිදු වගකිමක් දරන්නේ නැති අතර ආරක්ශාසහිතව වැඩ කිරීම ඔබ සතුය.
ස්තුතියි 🙏🙏
#Note: - This channel or I are not responsible for any accidents or damage to the product you may have during any repair work and you have the right to work safely and securely.
Thank you