Insignia NS-27LCD TV, got a nasty static shock, and now I just get a blinking red light on the front. Nothing else happens...I left it unplugged for a year (yes, a year lol) and I am still having the same issue. I looked at the power supply and I see no evidence of scorching or bulging/leaking caps. The small fuse on the power supply is intact. Based on my searching, it would seem the protection circuit is stuck. Though I have no idea where this circuit is located, even after exhaustive searching. My first guess is I need a new main/cpu board, but before dropping any money on this thing I wanted to get some advice on this. I have a cheap multimeter, but not a lot of experience using it. I could probably get readings with some handholding. Also, I seem to have forgotten where the various plugs from the power supply go at this point, and I am unable to find a schematic anywhere, if there is one even availble. Thanks for any and all help. Jason Cross

Good day!!!!


That problem is usually have 2 causes..Its either power supply board or main board..
Please take this steps on how to determine the problem:
1. Open the back cover.
2. Check the power supply output...It should have 5vdc for the main board..12vdc or 16vdc for the audio and 24vdc for the back-light inverter..
3. If those 3 voltage supplies have encountered voltage drop...The problem could be on power supply board..
4. If the power supply output is normal..The problem could be on the main board...
5. If the problem is power supply you should check if the capacitors are bulged on the top and try to replaced it..If you can't do that you can purchased new power supply board..
6. If the problem is on main board there is no D.I.Y repair on that so you need to buy a new main board that fits to your TV..


Hope this solution will be helpful..


Thanks for using fixya...

Hi,
Do one thing remove the connections to the inverter board and power on the tv. You can't be able to see any thing on the screen. Check with connecting the cable is there is any sound. If there is sound then you have to replace the invereter board. Reparing the inverter board is not possible.Because the parts will not be avilable anywhere. The inverter board will look like on in the picture. You hve to remove the connection on the inverter board which is comming from the power supuply.
ok

Hi, well before one can work on a set, one MUST first obtain a service manual, it's almost impossible even for a professional to service a set without one it's just that simple. Now in the manuals also are the troubleshooting procedures and steps to take to isolate and hopefully repair the unit.
But I must warn you that most times DIY repairs will not be successful, most often one simply spends good money after bad, with times and money spent with no outcome. Honestly it will be less expensive and less hassle if you simply take it to a manufacturers recommended service center, contact a local or head office and ask for a referral, and then simply ONLY ask for a "Quote" as to the costings for any prospective repair and go from there. For all you know it may indeed be unrecoverable?
Anyway I have included below a couple of old help postings i have iterated before maybe these will help, if you feel you must DIY. I am NOT trying to "Rain on anyone's parade" as it were, I am trying to give you the benefit of over 35 years experience and to save you time and money, and maybe more importantly your life! I was horrified by your comment "I received a nasty shock" PLEASE if you do want to service things get an ISOLATION transformer and use it, it's NOT safe servicing things without one.
It ALL starts and ends with the power supply, as, if, that isn't right nothing else can be. But you simply cannot do anything without a Service Manual. In this it has everything one needs to repair the set. OK if it is shutting down, after that amount of time, of working and then faulting, then it is most definitely a "Thermal" problem, the way we "Find" problems such as this is "Freeze Spray" you use this on each component that is suspected of being the "Culprit" and you will soon,find that errant component. Now also not every fault is a Capacitor, I see many, many people that think, that Capacitors are always the "Culprit" now while that may be true in a few cases, a faulty Electrolytic Cap, or ordinary, Cap goes faulty, this is only a SYMPTOM, something has damaged those caps causing them to "Fail". One MUST always find the root "Cause", otherwise if you just treat, the SYMPTOM, the "Cause" will just make the "Symptom" come back, in short order, as the prime cause still, hasn't been fixed., Now Capacitors hate AC ripple, or Over Voltage. Thats it. Oh.. and Heat, if these Capacitors, are too close to a Heat Source, then thats a prime cause of failure. Resistors, hardly ever go faulty,and if they do, it is generally obvious. However it doesn't hurt to check values with our Multimeter. Remember though resistors are made, with up to 20% tolerance from stated value, as such, are not too critical, unless in Timing circuits etc. Always check, the Values, of resistors, as with any other component, with the power OFF. Now Diodes especially "Zener Diode", are another thing to check, those and ordinary "Signal Diode" should always be suspect. next we have Transistors and IC's. The Transistors MUST ALL be checked to see if they have a good, "Junction" this is done, with our meter set to "Diode Test" and usually are about 0.6 to 0.7. With IC's you must check, voltage levels, or Logic Levels, going in and out, have a look at the circuit diagram, and it will tell you what they should be. It is a good idea to always measure the Power Supply voltages, see if a "Rail" is Low, that will be because some component has gone somewhat or all short circuit, to Earth, now, if the "Rail" is Higher, suspect an "Open Circuit" component, like a Diode, or Transistor. The voltages expressed in the manual are spot on, ANY variation MUST be investigated. I have been doing all this for over 30 years now, and I do indeed wish, we could have a set of "Symptoms" and be ables to say.. "Oh that;s the so-in-so and replace this" however unfortunately this although does happen, most "Symptoms" can have literally tens, of "Causes" all often "Interlinked" One simply has to do a methodical troubleshooting procedure, and always think, "are my Voltages Correct" as this is how, you Fix the problem, by making them so. Keep up the good work. If that link above doesn't furnish a Service manual, it is imperative you get one, even if you must pay for it. It will pay for itself in about 2 mins.

IF you wish to try to fix it yourself, and I do not recommend it. FIRST, you Must get a service manual, then you need, equipment, an Oscilloscope is a MUST HAVE. Also a Multimeter, and soldering iron, a DE-soldering station, an anti-static wrist strap, (Any TV is extremely static sensitive). Now FIRST you must make sure the Power supply is 100% as if this is NOT then nothing else can be. Also there are safety considerations, any unit that can cause a Fire or Explosion, or both, needs to be attended to with the utmost care. As if it isn't done correctly, a catastrophe is indeed possible, Faulty sets can cause a fire, and a fire in the middle of the night, I believe is not good. And any person that has attended that set, will be held to account. Now with that understanding, I guess proceed if you wish. Troubleshooting say if it is shutting down, after a certain amount of time, of working and then faulting, then it is most definitely a "Thermal" problem, the way we "Find" problems such as this is "Freeze Spray" you use this on each component that is suspected of being the "Culprit" and you will soon,find that errant component. Now also not every fault is a Capacitor, I see many, many people that think, that Capacitors are always the "Culprit" now while that may be true in a few cases, a faulty Electrolytic Cap, or ordinary, Cap goes faulty, this is only a SYMPTOM, something has damaged those caps causing them to "Fail". One MUST always find the root "Cause", otherwise if you just treat, the SYMPTOM, the "Cause" will just make the "Symptom" come back, in short order, as the prime cause still, hasn't been fixed., Now Capacitors hate AC ripple, or Over Voltage. Thats it. Oh.. and Heat, if these Capacitors, are too close to a Heat Source, then thats a prime cause of failure. Resistors, hardly ever go faulty,and if they do, it is generally obvious. However it doesn't hurt to check values with our Multimeter. Remember though resistors are made, with up to 20% tolerance from stated value, as such, are not too critical, unless in Timing circuits etc. Always check, the Values, of resistors, as with any other component, with the power OFF. Now Diodes especially "Zener Diode", are another thing to check, those and ordinary "Signal Diode" should always be suspect. next we have Transistors and IC's. The Transistors MUST ALL be checked to see if they have a good, "Junction" this is done, with our meter set to "Diode Test" and usually are about 0.6 to 0.7. With IC's you must check, voltage levels, or Logic Levels, going in and out, have a look at the circuit diagram, and it will tell you what they should be. It is a good idea to always measure the Power Supply voltages, see if a "Rail" is Low, that will be because some component has gone somewhat or all short circuit, to Earth, now, if the "Rail" is Higher, suspect an "Open Circuit" component, like a Diode, or Transistor. The voltages expressed in the manual are spot on, ANY variation MUST be investigated. I have been doing all this for over 30 years now, and I do indeed wish, we could have a set of "Symptoms" and be ables to say.. "Oh that;s the so-in-so and replace this" however unfortunately this although does happen, most "Symptoms" can have literally tens, of "Causes" all often "Interlinked" One simply has to do a methodical troubleshooting procedure, and always think, "are my Voltages Correct" as this is how, you Fix the problem, by making them so. Keep up the good work. If that link above doesn't furnish a Service manual, it is imperative you get one, even if you must pay for it. It will pay for itself in about 2 mins. Now just replacing boards will most likely just end up with more faulty, boards, as related you MUST ensure that you have the cause of the event, before we change anything. I have seen so called, "Techs" replace every board, and virtually every component, and that STILL didn't fix it, because the "Fault, or Cause" lay elsewhere, and had not be repaired FIRST, you see that FIRST STEP, like everything in life, is, CRITICAL.

It probably is a power supply problem, it is common with that model, the caps might look good, but the smaller electrolytic caps are probably no good, you really need a esr metter to tell if you have good or bad caps, just because the cap looks good, that don't mean it is, Change the elctrolytic caps on powersupply module, or replace power supply. www.partstore.com

You might wish to unplug the TV for an hour or more. If this power reset does not allow the TV to turn on component failure is indicated. These sets are assembled using the wave soldering process they are known for having cold solder connections.

The safety circuitry shuts the TV set down or will keep it from turning on when it detects a problem. This model of TV has over 2,000 parts, which includes millions of transistors inside the integrated circuits. The capacitors will change value, leak and become defective. Resistors will change value and burn. Diodes and IC can go bad.

This may have a domino effect and cause other parts to fail. Replacing one defective part may make the TV operate for a short time but the part will fail again if the parts that caused the failure to begin with are not replaced.

The only way to know for sure which parts that are no longer within factory specs and for a proper repair all the electronics must be diagnosed by someone with the correct electronic test equipment specifically designed for TV service and the skills to use the test equipment. I wish I could tell you there was a quick fix or button to push that would fix the TV but that is not the case or the solution needed to get the TV operating correctly.

Hi, Connect your multimeter probes to your multimeter. Observe the correct polarity. The red probe is the positive one, and the banana jack at its end is plugged into the red plug on the multimeter. The black probe is the negative or common probe and its banana jack is plugged into the black plug on the multimeter.

Set your multimeter function by turning the function knob or selecting a function button to measure voltage. Select either an alternating current (AC) or direct current (DC) voltage, depending on the output of your specific power supply. Most household power supplies produce a DC voltage.

Unplug the electrical device and remove any housing on the electrical appliance in order to gain access to the power supply. Being careful not to touch any of the electrical circuits, turn on the electrical device, which will also turn on the device's power supply. Make sure it is plugged into the right power source. Most household electrical appliances, other than dryers and ranges, operate by plugging into a typical 120 volt house circuit.

Touch the multimeter probes to the power supply output terminals. Make sure your hands stay on the insulated parts of the probes. Observe the correct polarity. Power supply output terminals are usually marked with a positive (+) sign and a negative (-) sign. Touch the red probe to the positive terminal and the black probe to the negative terminal.

Read the multimeter display for the power supply's output voltage.

After determining the voltage, remove the probes and turn off the multimeter. Unplug the electrical device and put the housing back on.





Static Electricity Warning
Some components on the power supply are CMOS integrated circuits and are therefore sensitive to static electricity. Before touching the circuit board, I make sure the TV is unplugged. Then, I touch a piece of metal on the back of the TV that is grounded, i.e. part of the metal frame or one of the mounting screws or mounting posts of the power supply board. This will dissipate any stored static electricity by the body and discharge it to ground. CAREFUL!!! This should only be done with the TV turned off and NOT plugged in. Otherwise, one might touch something with HIGH VOLTAGE and receive an electrical shock. In particular, stay away from the large heat sinks with the yellow stickers on them indicating high voltage.

Overview
The power supply is the large circuit board in the middle of the TV. It has many transformers, large capacitors, and a couple IC's. There are eight connectors attaching the power supply to the other circuit boards on the TV. Looking closer, one can see that the power supply(Model#:PSPF651B01A) is manufactured by Samsung, as is the plasma screen itself. The supply provides about ten different voltages; 190V, -180V, 60V, etc for the plasma screen as well as 3.3V, 5V, and 12V for the logic and digital electronics.

The power supply circuit board contains a wealth of information including its part number and a table of the different voltages it produces along their signal names(Va, Vscan, Vstb, etc). Test points for all these voltages exist on the left side of the board(looking at the power supply as it is mounted to the back of the television).

How to test
I used a multimeter to probe the voltages at the testpoints with the TV turned on. BE CAREFUL!!!! This is of course highly dangerous as HIGH VOLTAGES occur on the power supply and the TV was not meant to be run with the back off. Touching certain points on the power supply while it is powered can KILL YOU!!!! To be safe, don't touch ANYTHING inside the TV whilst it is plugged in. In fact, if you do not know what you are doing, just stop here. No point killing yourself over a stupid TV.

If you dare....
The RTN node (seen on the silkscreen at the top left connector(and others) ) is basically the common grounding point and is connected to Earth ground, the shiny metal backing of the plasma screen, and all the metal mounting pegs that the power supply is mounted to. The black or negative lead of your multimeter should be attached to this point. I just stuck the black probe into one of the mounting studs and let it hang there (out of the way) so I could probe using the other(red) lead of the multimeter with one hand.

Start off with the TV unplugged and turned off. Attach the negative or black lead of the multimeter to any mounting stud near the power supply board. Now plug in the TV and make sure nothing explodes. Now turn on the TV with the remote control and again make sure nothing explodes. Is the screen blank? If so, good. You'll be able to probe the test points on the power supply to determine which voltage is not being produced. In my case, it was Va which is supposed to be 60V. Make sure to make a good contact between the testpoint and the multimeter probe. If the contact is poor, the voltage readout may look as though it is fluctuating between the spec'd voltage and some lower voltage. For example, if the spec'd voltage is 180v, not pressing hard enough to connect the probe and the testpoint may result in a readout that wanders between 180v and 50v.

If all the voltages are being supplied and withing spec (as shown on the power supply's silkscreened voltage table shown in the fourth picture below), your power supply is most likely functioning correctly. Your problem may lie in a different area. Numerous people have mentioned a problem with their Y-Buffer, the circuit boards flanking the left and right sides of the plasma screen. Specifically, whitby905 (see the comments section) has found that the lower left Y-Buffer board was contacting the metal plasma screen backing and had shorted out. If your power supply checks out, look and smell for any indication that any of the Y-Buffers have shorted to the case. You may have to remove them and look on the back for shorted solder points. I don't have any pictures of this situation besides the one from whitby905 in the comments section.

My problem was with the Va voltage of the power supply so I will continue discussing it in the next section "Debugging on the Bench."

Know how to solder from the below link...


http://www.kpsec.freeuk.com/solder.htm