Smps fuse

14.05.2021 By Dujin

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SMPS repair - fuse blows

For a better experience, please enable JavaScript in your browser before proceeding. SMPS repair - fuse blows. Search Forums New Posts. Hello everyone. The TV set does not start at all. I have checked the smps, and the mA fuse SI on the shematicnear the main capacitorkeeps blowing. All diodes are OK and volt is measured on main capacitor C The PowerMOS transistor seems short circuit and the fuse blows. I have attached the shematic of the board. Any help will be appreciated. Thank you very much.

Fotis D. Scroll to continue with content. When i remove it and testoff the boardit's ok. Then put it back, turn on the tv set, fuse blows and T seems short circuit again. When i first checked this tv set, i could measure some voltages on the secondary of the SMPS, but was half of the appropriate values for example 4 Volts instead of 8. Thank you. The only guy here I know that might be able to help is R! My last attempt to repair a CRT didn't end well.Search for the part s number you wish to receive samples.

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smps fuse

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Smps fuse and transistor blown up. Thread starter ejazbeyond Start date Dec 26, We are using a smps for our comm pcba relay and a current sensor, which uses 4. We are controling one phase of a three phase 5hp water motor.

smps fuse

Also smps circuit and relay output are in parallel so output load doesnt effecting our smps. Problem is when we tested our complete device in lab on a room heater of 2kw its working fine however when tested in field on dol starter type 5hp motor our device fuse 3A and transistor s and s blown up. We are controling realy input which 12v which in turn one phase of motor.

ChrisP58 Well-Known Member. We are using a Dol starter which is connected to motor. Two phase out of three DOL starter get from main supply and one phase via our device gsm based controller.

We have also protected our circuit from back emf by using flyback diode. What prevents the motor from burning out if two phases of it are connected but the starter but the third phase is not connected?

On the schematic you need to show the input supply to the smps. I am thinking that its's input voltage may be the problem with the strange way you are switching two of the three phases. Our device is connected between main supply and DOL starter. One phase of dol starter connected via our device. I have drawn rough schematic which help u understand.Halu sir.

In this case substitute the main fuse across the two pins of the main fuse holder with a series bulb. You can make one easily as shown here below. Replace the main fuse with the series bulb Watts and apply the power. If the bulb remains bright, power off the TV and remove the power cable from the socket.

Go to the switching transistor and cut the middle leg collector with a side cutter. Then apply the power again to the TV and observe the bulb again. If the bulb now goes dim, this means the switching transistor is shorted and must be replaced. If the bulb remains bright means the short is before the switching transistor. Let me point out here that the only shorted component that can make the bulb to remain bright are the only component with one leg on the live voltage and the other leg on the ground.

Kindly refer to the follow diagram for more information. On the diagram I have circled two components with red colour V and C I have personally an experience where the entire component with blue circle tested okay and still the bulb was bright, testing transistor V 2SCC was found shorted collector-emitter junction and after replacing it the problem was solved. Below you can the actual component which you should check out when you suspect the short is before the switching transistor.

Sometimes a component may be failing under load which means getting the culprit is not easy with a meter. Tip: in this case solder out one leg of the suspect component one by one and applying power, the last component you remove and the bulb brightness disappear is the actual culprit.

If any of the component below short the bulb will remain bright. For the supply using control I. C, then you will have to find out which pin is for the main Vcc vdc or vdc and cut it out and repeat the procedure in the previous example.

Unknown December 11, at PM.A switched-mode power supply or SMPS or sometimes called the switcher, is an electronic power supply that incorporates a switching regulator to convert electrical power efficiently.

An SMPS transfers power from a source, like any other power supplies, like mains power, to a load, such as a personal computer, while converting voltage and current characteristics. So what if your SMPS got broke? With a little electronics know-how and some guides, it should be simple. Knowledge is power. The first thing to do is to take a closer look at the SMPS structure. It would be best to look at the generic block diagram of a SMPS.

The image below is a simple structure. SMPS are dangerous circuits, so before starting to troubleshoot, safety should come first. Just reminders, half of the components are directly connected to the mains voltage, so voltage shock would be painful. A large storage capacitor is charged at high voltage and can be dangerous even when the mains supply is disconnected. The capacitors could stay charged for a long time since not all SMPS include bleeding resistors or even some might be broken.

It is always good to do a visual inspection. First, disconnect the SMPS and make sure all capacitor are discharged. Burned resistor can be spotted by their black colour and bad smell. It is important to always check the ferrite transformer, if it looks burned and smells badly, we can give it up because it may sometime have shorted turns and it will be a nightmare to repair or find a replacement part.

If the transformer if faulty, it would be best to replace the whole SMPS and will save us a lot of time. SMPS can fail in many different ways, but the most common would be no output power at all. With this, start by checking the input fuse.

If the fuse is good but there is no output, probably all the semiconductors are good and it could be easy to fix.

If the fuse is open, then something went really wrong in the circuit. Typical problems are blown up power transistors or rectifier diodes, especially on the primary side. There are times when the SMPS is only partially working; it may start for a fraction of a second then shuts down or it may pulsate trying to start every few seconds and shutting down after a fraction of second, or it may producing a wrong output voltage.

Probably all power semiconductors are good, so the first thing to check are the capacitors. Often the cause of SMPS problems is the electrolytic capacitors. In what we call cheap designs, where thermal dissipation is a bit too close to the limit, and a choice of components a bit too cost-oriented, electrolytic capacitors are oftentimes real time-bombs that will eventually fail or sometimes explodes.

The liquid electrolyte inside these components tends to evaporate and dry out completely altering the characteristics. You are commenting using your WordPress. You are commenting using your Google account. You are commenting using your Twitter account. You are commenting using your Facebook account. Notify me of new comments via email. Notify me of new posts via email. Blog at WordPress. Menu About Tweets. Safety is our primary concert.

No output, good fuse SMPS can fail in many different ways, but the most common would be no output power at all.Switch mode power supplies SMPS are now standard for the majority of our home appliances.

Old fashioned linear power supplies based on mains frequency transformers are disappearing, mainly because of their cost, their large size and weight. Switch mode power supplies are everywhere; here are some pictures of their guts. The big high power components and small heat sinks are typical of SMPS. These devices are incredibly reliable, but being very often left powered all the time even when their load is switched offthey still are the weak link. Components are fed with high voltage, they get warm, they age quickly because of the full time operation and when there is a surge, the SMPS is the first stage concerned.

Many problems with our home appliances are due to SMPS faults. So, I summarized in this page the basic ideas and the tricks that I use the most. Here, I suppose you have a perfectly designed circuit that used to work perfectly and suddenly failed. If you're trying to debug your own design, still some of these tricks apply, but you'll probably need much more than just this article.

First, let's take a look to the generic block diagram of a SMPS. The mains power enters the circuits through a line filter, it's rectified and smoothed out to obtain a high DC voltage a few hundreds volts. On the secondary side, the voltage is rectified and filtered.

smps fuse

Switching transistors are driven by a control circuit that senses the output voltage and input current and regulates accordingly. This control circuit is very often on the primary side and often powered by an extra winding on the transformer. A sample of the output voltage is fed back via an opto-coupler.

In some cases the control circuit is located on the secondary side and drives the transistor s via a small additional transformer. All configurations have some additional circuit to allow the controller to start at power-up. Structure of a SMPS.

There is always a very clear separation between the high and low voltage sides primary and secondary sides. You can observe it on the bottom copper side of the PCB as a larger spacing in the tracks. Some times the solder mask varnish is removed in this area or there are holes and slots to increase insulations. On the pictures in this page, this separation is often marked with a dashed red line. This SMPS uses classic-style through hole components.

The high voltage side is on the left of the dashed red line. Here, the controller uses SMD technology and is mounted on the bottom side.

The large SMD diode is the low voltage rectifier.Search for the part s number you wish to receive samples. Or, visit the sample center page. Littelfuse, Inc. We use cookies to collect information about how you interact with our website and to remember you. We use this information to improve and customize your browsing experience and for analytics about our visitors on this website and other media.

To find out more about the cookies we use, see our Privacy Policy. By continuing, you agree to the use of our cookies. By selecting among and accepting to our use of the cookie categories below, you direct Littelfuse to store cookies on your device and disclose information as described in our Privacy Policy.

smps fuse

If you do not direct us to collect any categories of cookies, a single essential cookie will be used in your browser to remember your preference not to be tracked. When you use our website, we collect personal data about you and your use of the Website, through cookies and analytics tools. We may also collect personal data such as your name, job title, company name, address, email address and telephone number either directly from you or by combining information we collect through other sources.

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SMPS External

For example, these cookies remember your preference not to be tracked and identify trusted web traffic. These cookies collect information about how visitors and users use our website, applications, and services.

These cookies enable us to improve our website, for instance, by ensuring that users are finding the required information.

How to Repair SMPS in हिंदी, Switch Mode Power Supply Repair in Hindi Step By Step 100%

These cookies don't collect information that identifies a visitor or user. All information collected by these cookies is aggregated and anonymous. These cookies allow our website, applications and services to remember choices you make such as your preferred language and provide enhanced, more personal features.

They may also be used to provide services you have asked for. The information these cookies collect may be anonymized and they cannot track your browsing activity on other websites. These cookies are used to deliver advertising that may be relevant to you and your interests. They are also used to limit the number of times you see an advertisement as well as help measure the effectiveness of an advertising campaign.

They remember that you have visited a website and this information is shared with other organizations such as advertisers.