The Right Way To Discharge Capacitor In Switch Mode Power Supplies by Jestine Yong
Switch mode power supply contain some large filter capacitors that can hold dangerous charges even if the unit has not been used for several days. Typical values of this type of filter capacitor are 220uf 250volt and 330uf 400volt! If you are going to work on the power supply circuits, it's a... I use a 2.2k ohm 10 watt resistor to discharge the high voltage capacitor in a switch mode power supplies. ... There are three ways to discharge the big filter capacitor in a power supply. ... I once blowed the power section using this method.

The Importance Of Current Sense Resistor In Switch Mode Power Supply by Jestine Yong
Current sense resistor is usually located in the switch mode power supply section. Newer version of monitor-the b+ (boost) circuit also have this current sense resistor. If you repair electronic equipment especially the switch mode power supplies, the current sensing resistor is connected to the... In some cases where overload happen-the power section will blow and most of the time the components changed are fuse, power fet, pwm ic, zener diode and current sense resistor. ... In monitor power supply where pulse width modulation (pwm) ic UC3842 are used.

Samsung 153V LCD Monitor Power Supply Repair Tips by Jestine Yong
Troubleshooting Samsung 153V LCD power supply is just like troubleshooting those crt type. This monitor came in with no power symptom. If you are first time repairing this type of power supply, I recommend you to first remove the switch mode power transformer. ... Testing the switch mode power supply primary winding with a dick smith flyback tester shown green bar which indicated good winding. ... After carefully checking all the components in the power supply section, I found the filter capacitor do not have any reading using digital capacitance meter (open) , the two round type fuse also...

Understanding TOP223P And PQ05RD11 IC In Thompson DVD Power Supply by Jestine Yong
The TOP223P pulse width modulation ic is designed to work in switch mode power supply (smps). It is mainly used in the audio/video electronic equipment. Computer monitor rarely use this type of ic. In this article, I would like to share with you that not all switch mode power transformer must... Conclusion-Troubleshooting power supply that used the TOP223P ic or other family type is very easy if you understand how power supply work and if you have the schematic diagram of a particular equipment.

ATX Power Supply Repair And Troubleshooting by Jestine Yong
Customer ATX power supply came in with the complaint of intermittent no power. When testing it with power on, I could see that the fan is not rotating. Not only that, some filter capacitors also became bulge because of the heat accumulated inside the power supply. ... If you switch off a working power supply and power removed, touch the power transformer, you could feel it is quite warm. ... The failure of the fan would not suck out the heat generated by the components especially the switch mode power transformer.

How To Repair Dell E152Fpb LCD Monitor by Jestine Yong
The complaint for this DELL E152Fpb LCD Monitor was when switched on has power (LED lit) but no display. LCD Monitor is different from the CRT Monitor where you could feel the static at the front of the picture tube or hear the rushing sound from the high voltage produced by the flyback... It could be components that are faulty that dragged down the line or it could be the switch mode power supply itself that don’t produce enough power. ... Because of these clear answers, we can conclude that the switch mode power supply is working fine.

Testing Capacitor-How To Test A Capacitor When Breakdown Under Load by Jestine Yong
Have you ever come across power problem where once you switch on the power supply and the fuse blow? You have checked all the components in the power (primary) and secondary section and all the components seems to be ok! Where is the fault? A fuse blown are usually caused by a shorted bridge... Everytime when i switch on the power supply the fuse blow immediately (the fuse became dark color and this indicate that there is a major short circuit in the power supply). ... I have checked all the components in the power supply and can't find the culprit!

How To Troubleshoot And Repair DELL E151FP LCD Monitor With No Power Problem by Jestine Yong
The DELL E151FP LCD Monitor came in with no power symptom and upon opening up the cover I saw few components that were burnt. R623 (4.7 ohm) burnt at the side and you could still recognized the resistor color code. The current sense resistor (0.68 ohm) outer layer partly had came off and... Though this part number is mostly used in switch mode power supply, my electronic supplier does not have this stock. ... After all components have put into their original place or location and of course with the power transformer soldered, I don’t immediately switch on the power supply.

Testing Transformer - 3 Proven And Simple Methods To Test Transformers by Jestine Yong
Testing transformer is very easy if you follow the procedure explained in this article. Generally there are two types of transformer in the market i.e. the linear type and the switch mode power transformer. In this article I’m only explain on how to test the linear transformer. ... Lastly, checking switch mode power transformer is different from testing linear transformer. ... For some transformers like the UPS (uninterruptible power supply) you need wiring diagrams to assist you because there are so many secondary windings and you may get confused.

How To Repair Macroview Mp712s 17" CRT Monitor by Jestine Yong
The complaint for this Macroview mp712s 17” monitor was no power. Once the cover was removed and power on, you could hear a soft “chip-chip” sound indicating the power trying to come out but something had caused it to shut down. The LED indicator has no light at all. ... Scanning across the board found quite a number of dry joints in the circuit and the most obvious part was the secondary side just after the switch mode power transformer area. ... Placing the red probe to the supply line as shown in the photo and black probe to cold ground with power on, I observed there was some unusual...