Modification Of LED TV SMPS[ stands for switched mode power supply]

 

 

 

 

 

 

 

 

 

 

 

 

 

This  24 Inch LED TV came in with the complaint of no power.

Generally no power symptom mostly are cause by the failure in the power supply board. It can also cause by failure of the mainboard because the power LED signal is coming from the mainboard MCU IC. No matter which board failure, I still need to open up the cover and to troubleshoot it. Once the cover was opened, I focused on the power board first.

 

 

 

Visual inspection did not see any unusual problem be it on the components or the wiring cables.

 

 

The main fuse was tested good thus I checked on the main filter capacitor and there was 325 volt present at the two pins. I can actually go straight to check on the output DC voltages at the connector but somehow wanted to show to you how to measure the main filter capacitor voltage. 

I further checked on the surrounding components in the primary power section and all components checked to be good.

I suspected it was the power IC that have issue but the problem is the part number of the power IC was removed. It is slightly difficult to know each of the pin function especially to the beginners. 

In order to remove the guesswork if the power IC is the cause of the problem or not, I installed the power module (5 pins) to test it out and see if the power will come back or not.

I connected to all the wires to the 5 important points as shown in the diagram below. Sorry if the diagram is blur.

Below is the photo of a successfully installed power module and I tightened the power module to the nearest casing to dissipate the heat. See the two photos below:

Once the power was turned On, the picture immediately appeared.

This has proof that indeed the original power IC got problem.

Conclusion- With the external power module installed and the TV worked, this has saved me tremendous amount of time. I do not need to know the exact part number of the power IC. The installation time was fast provided you know where to solder the 5 points.

 

 

 so long as u have all skills needed u can sort-out all problem related to power supply, this including understanding circuit and how current flows to all various power supply section . for more information contact   0718814978 / 0735149318.  https://www.facebook.com/Dick-Tech-Electronics-Repair-Center-1525939240750763  

 

 

 

 

 

 

AUO 11303 LCD TV T-Con IC Faulty

 

AUO 11303 LCD TV T-Con IC Faulty

 

 

 

 

 

 

 

 

 

 

 

 

This Changhong LCD TV came in for repair with the complaint of no picture but have sound. In fact when you look closely at the screen you will be able to see the backlight was lighted. There can be few causes of such problem.

Instead of guessing what might be the cause, I opened the TV cover and checked on the power supply DC output voltages. All DC output voltages were found to be correct.

The next check was on the T-con board IC (AUO -11303) and the cable connection. I reheated the T-con IC and reseated the cable (and cleaned the connector) and the problem turned out to be the same. When I turned the TV On, I could only saw the backlight lighted without any picture-see the three photos below:

Next step was to replace the AUO-11303 IC directly and retest it.

After the replacement of the ic, the picture came back normal-see the photo below 

 

Conclusion- If the power supply DC output voltages are good then focus on the T-con board. Check the VCC supply to the T-con board IC and make sure the IC is not too hot to be touched and reheat it.

If the problem still not resolved then direct replace the IC and retest it. If after the replacement of the IC and still not be able to repair it, the next step would be to find out the service manual and start checking the important signals pin in the T-con board.

 

 

Microwave Repair (failed interlock switch)

 

Microwave Repair (failed interlock switch)

 

 

 

 

 

Microwave oven kept blowing fuses and upon opening it was obvious the top interlock switch was no longer working.

Rather than order the cheapest replacements I opted to get some quality units at considerably higher cost due to the claims:

• “These are built quite a bit more robustly in our opinion”

• “Quality Item, Will Outlast Original by Years”

as I wanted the repair to last.

Only the top (of three switches) had failed but I replaced both the top and bottom as they were of the same type (normally open) and I could combine shipping; the middle (normally closed) I left

Fast forward a few months and it was blowing fuses again, often when the door was opened after the cooking had completed; made me suspect the middle switch that I had not replaced, but upon inspection it was the top switch again, even though I had invested in a supposedly better made unit.

Opening it up showed that the switch was in good shape internally but that the actuation finger was made of a plastic that had melted where it touches the switch mechanism.

The fix was interesting in that I then took the actuation fingers from the old cheap switches which seemed to be of a plastic that has a higher melting temperature and used these to replace those in the ‘superior’ switch.

The microwave is now working just fine again and hopefully will now really “outlast the original by years”. Fortunately my Wife is quite patient as I try and figure out what is wrong with broken devices around the house.

 

 

 

Samsung smart led tv came in with backlight problem now fixed

 

Samsung smart led tv came in with backlight problem now fixed.

Blank half screen or dark half screen …This might be backlight strip of one side, check all the led trip and by testing each with digital meter or backlight tester. Again check the voltage of each rectifier diodes of inverter section. below photo has the real sample and and behaviors  

 

2  After removing the tv cover I may see all parts eg. Main board , power board . NOTES. Inverter board is combined  in power board so there not separated, however u can test each circuit independently  to establish which section is failing  . lets do some introduction of above related issues of tvs.. blank picture or no backlight but sound ok. this may backlight problem or led driver failure. When u power up tv the power board generate standbys volts 5volts or 3.3volts depending on designer topology, the standby well be feed to main CPU or main processor and it will release dc volts to power up led power on, you will be pressing power on button by using remote or tv keys this is now to turn on tv .. The power supply will produce 5volts which will be standby then again 24 or 12 dc volts to inverter board. The main board will now be generating on off command to turn on the fully power supply ….

 

 

 

 

    Now when the tv cover was removed I did some testing by checking all the components and found everything ok, I also did voltages test  in inverter section and there were almost 140dc volts which means all were working well.  I opened everything and removed LCD screen and I were able to reach to led backlights it were two strips, one strip had a burnt mark which indicates things were not good at all on led strips backlight . all two strips replaced and turn on tv  I could see good images with fully backlight on tv screen.

Check  after screen removed, see where two led strips are inserted.  Notes. Be careful when u are dealing with LCD screen panel because u may break it if u don’t concentrates on it , the screen is very expensive so you should be keen to avoid to break it.

Above are two faults led strips and they are replaced with a new one . But sorry I forgot to take the photos of a new led backlight due to customer speeding up me, she wanted it to fixed very fast  so that she take off.

 

 

 

Conclusion the trouble shooting of any electronics equipment is easy but also tough at particular if u have no enough experience but to those has experience  not tough 

 for more information call, email, text and WhatsApp .. 

 

 Contact on +254 718814978

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

oxygen concentrator came with no power now repaired

 

                                        OXYGEN CONCENTRATOR WITH NO POWER REPAIRED

                                         MODEL NO. AMT-8D. 

 

OXYGEN CONCENTRATOR –is a medical equipment that concentrates oxygen by using a gas supply to filter nitrogen from surrounding ambient air. it is used for supplying oxygen to individuals with breathing problem or related disorder, difficulties . The following photo is how is being used to human being. This device is well known as is playing a very supreme role in our life, it also controlled electronically so whenever this circuit becomes faulty, the device system will not function well and it can even go off completely. The following are the faults u may experiencing when u are coming over to use this equipment.

 

 

 

 

 

 

       FAULTS AND BEHIVIOURS OF A DEVICE WHEN ONE OF THESE OR BOTH BECOMES ABNOMAL

Kindly I will not goes into details to each faults indicated below but these are the problem u may meets on any electricals and electronics equipments when you are using or dealling with them

                                                               NO POWER

                                                               BREAKDOWN WHEN IS UNDER FULL LOAD

                                                               DISPLAY FLICKELING

                                                               FAILING TO GENERATES OXYGEN

                                                               DISPLAY ON BUT KEYS NOT RESPONDING

                                                                                                   

                                                                                                     

                                                                                       

                TROUBLE SHOOTING OR FAULTS FINDING PROCESS

 

                                                                   

                                                                                         

                                                                                         

              REPAIRED OXYGEN CONCENTRATOR EQUIPMENT      

                                                                                         

                      NO POWER-  AS I said this device was fixed due to power failure, when it turned on there were no sign of life to this medical equipment this is because no power were flowing to the system of this equipment  . Power failure to any electronics equipment might be cable, or short-circuit to any components along power supply board .eg. Short-circuits of fuse, diodes, e caps, transistor or primary windings of a transformer, but depending on engineer or designer topology.  the first thing was to check power cold cable and it was tested okay then  I proceeded to power board for further testing, NOTES.. Take all the precaution first when you are dealing with power supply board at particular when you are correcting the voltage, failure to which u will be electrocuted … very nasty shock.. With my digital multimeter I managed to test each components on power board, guess what?   The filter coil and two ac capacitor was damaged and they had a burnt mark both of them.  Below are the faults components …

 

                 

These are the components which were replaced… NOTES I forgot to pick a photos of a new components. After replacement of these components I started collecting voltage to confirm if power supply is functioning well.  

 

           After repair, above are the collected ac input voltage …..238.7 was okay. The next was to take dc supply because dc voltage is used to power on display.

 

Now you can check 12 volts dc supply was taken all seems to be intact meaning the power board is now generating pulses well, there was an ic   generating pulses.

 

 

 

 

 

Here are the 5volts dc supply which were taken from this board. The 5volts dc supply  will power on the display so that when the display becomes on,  then it will wait for instruction from keys, when the key pressed will activates main processor and all the faction will be allowed according to the instruction given and all system will fully works perfectly. NOTES all these instruction given by main ic  is one will determines

all clock pulses like timing, the temperature and how many minutes or hours will machine generates oxygen.

 

 

Below two photos indicating the machine are in good condition, as you can see everything works well, the display looks okay with no issues.

 

 

 

 

Conclusion- the electronics repair works needs skills and good tools for trouble shooting, also before starts trouble shooting study the machine how works first so that you will not be wasting too much time for faults identification….      

 

         Contact     0718814978

   

 

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