Micromax 32" led TV Panal backlight repaired

Hi dear friends welcome again,
I received a call from one of my Costumer regarding 32" micromax LED TV no light, Only audio present. Since present generation attracted much more on LED/LCD  and curve TVs because of its HD clarity, compact & low power consumption design. Even technicians are updating the repair tips and technology to solve the variety of complaints which come to their work bench. My self as a technician keeps on upgrading the tips to support the Costumer for upcoming products on this latest technology. We always think  up-coming technology and will get ready to repair the new things. Until the basics knowledge its very difficult to operate such costly equipment’s. Here I would like to thanks Mr Jestin yong from Malaysia, Kent liew Malaysia and Humphery  kimathi from Kenya, for their great support  and contribution on repair tips sharing in the web and their books are helped me a lot in operating electronic equipment’s.
Let us begin with the story now, TV is at my repair bench, when I switched ON there is no back light at all and is ruining with very good audio. When I deeply observed with the help of my external backlight using my torch I can able to see the moving images. By this experiment it is concluded expect backlight rest of the circuit & everything is fine along with good LVDS signals flow to the penal circuit.
Now my main concentration is back light LED driver circuit DC-DC converter. When I checked the output voltage I am able to read 120vDC.
Then question in my mind when supply voltage is reaching LED circuit then why LED series not turning ON?? Really It’s very simple logic.
Started to remove the screws of panel even though composed with number of screws as in below box.

Here is the secrete I am revealing, Usually in LED TVs  light is illuminated through LED series parallel combination and which is powered by DC-DC Converter circuit.
Let us see the back structure how it looks when opened




LED  SERIES  AND PARALLEL COMBINATION AT BACK PANE

Normally voltages range is from 80 volts to 160 volts depending upon the panel design & size. In this condition if any single LED failed or burned entire LED ckt will OFF this is due to open loop in the path. Based on this concept I started to hunt the faulty LED using my external DC Source.

Checking the condition of the LED by using external DC- Source

Ultimately I got 2# Faulty LED mainly caused to break further current flow in LED Circuit. Now the next task is how to replace faulty LED??.I am really great full to Mr Jestin Young, who has shared how to repair such type of failure in his tips.




SHORTED THE DEFECTIVE LED PATH USING SOLDER LEAD

Just I shorted the failed LEDs path by soldering and made a closed loop. This is done by using my external DC source and conformed all the LEDs lit and started Re- assembling the panel unit.

After re-build powered the panel through the TV hardware & nice to see fine picture even though 2# LED failed condition.

BLUE BACK CONDITION TV ON

TV IS READY WAITING FOR VIDEO SIGNEL

 Customer felt very happy and he could not make out any bright difference in this condition. Even today TV is running fine and costumer is quite happy. This all about MICRO MAX LED TV Panel story. Hope you enjoyed let us meet next with one more interesting topic until then good bay take care.


Regards


BASAVARAJ BM

Impact of Dry solder on Electronic repair

Hi repair friends,

Well-come back again. Based on my repair History i am presenting this article so far what are all the problem faced while repairing electronic equipment’s like TV/Amplifiers/smps etc.

Solved many number of equipment’s by simply dry solder.

Simply removing good components checking caps/resistors/ICs and replacing the same failed my many repair task I was wondering how other local technician repaired my un solved equipment. Question in my mind what are all the secrete beyond him even he does not know to read the resistance value colour code and his basic education is less and his repair capable is high.

Based on my qualification people expectation is more but i was unable to solve simple problems. Non of the engg books reveal the repair tricks i promise you engg books says the entire working principle. But i am not telling you not to read engg books. They direct you to deep theory section block.

Because of my passionate in electronic to go in deep trouble shooting. I studied entire Television Book operation theory written by Sharma. even after this i have not become a success repairer.

Yes their is some shortcuts in repairing, but these things won't come by reading books or studying circuits. But they add a platform for repair success story which may come only by work experience. I spended lot of time in trouble shooting in my career learned a lot even today. Because of this I was able to write such a wonder full article. Each sentence revealed based on my work troubleshooting history.

Below are the basic short cuts to be followed before going to deep repair operation for any electronic equipment’s

1)  Visual inspection & Observation in the circuit board

2) Any caps Bulged are physical difference in appearance (Need to check ESR Values)

3) Any burning smell or Hot on both active /Passive components in ckt board

4) Any dry joints or track burned in stress area.

Above 4# Points to be strictly noted for any electronic equipment’s as a first aid before going to deep theory. By doing this 50% of the repetitive failure can be eliminated after section repair and repair service may last long life Yes finally the secrete beyond the local Technician is revealed. I started giving training for non-professionals and they succeeded in solving faults by following above method.

Below is one of the story which I solved the fault and charged the costumer who felt very happy.

One of my Costumer brought the induction stove for repair. The problem is having error information E3. Since the heart of the circuit is pic based microcontroller without proper data it's very difficult to trouble shoot the culprit.



DRY JOINTS

The brand name of the stove is PREETHI , googled an internet to see the code location and no clear information. Only say's could be internal fault in the circuit. Then what is that internal fault?

COMPONANT SIDE

Really i could not able to solve. Ultimately made my mind to return the unit. Before giving back taken the solder flux applied the stress area and re soldered the dry joints and followed above 4 steps and re-checked the unit. To my surprise now an equipment is perfectly alright working excellent it's a matter of dry joint. I have not used single component for this repair. Its completely Zero investment.



ANOTHER LOOK

This is one of the shortcut method what the local technician will do as one of the secrete.

WORKING  FINE AFTER REPAIR

Costumer felt very happy on resolving this. Further I continued above revealed steps as a first aid before going to deep analysis and even now I have been following same methods and solved N number of equipment’s. Hope you enjoyed my  article let us meet in the next session take care.

Regards

Basavaraj BM