REPAIRING AND NOT THROWING AWAY

REPAIRING AND NOT THROWING AWAY

Richtige Fernseher haben Röhren!

Richtige Fernseher haben Röhren!

In Brief: On this site you will find pictures and technical information about Service Modes, Circuit Diagrams, Firmware Update procedure, Disassemble procedure, Universal remote control set-up codes, Troubleshooting and more....

If you go into the profession, you will obtain or have access to a variety of tech tips databases HERE IT IS Master Electronics Repair !.

These are an excellent investment where the saying: 'time-is-money' rules. However, to learn, you need to develop a general troubleshooting approach - a logical, methodical, method of narrowing down the problem. A tech tip database might suggest: 'Replace C536' for a particular symptom. This is good advice for a specific problem on one model. However, what you really want to understand is why C536 was the cause and how to pinpoint the culprit in general even if you don't have a service manual or schematic and your tech tip database doesn't have an entry for your sick TV or VCR.

While schematics are nice, you won't always have them or be able to justify the purchase for a one-of repair. Therefore, in many cases, some reverse engineering will be necessary. The time will be well spent since even if you don't see another instance of the same model in your entire lifetime, you will have learned something in the process that can be applied to other equipment problems.
As always, when you get stuck, checking out a tech-tips database may quickly identify your problem and solution.In that case, you can greatly simplify your troubleshooting or at least confirm a diagnosis before ordering parts.

Happy repairing!
Today, the West is headed for the abyss. For the ultimate fate of our disposable society is for that society itself to be disposed of. And this will happen sooner, rather than later.

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..............The bitterness of poor quality is remembered long after the sweetness of todays funny gadgets low price has faded from memory........ . . . . . .....
Don't forget the past, the end of the world is upon us! Pretty soon it will all turn to dust!

©2010, 2011, 2012, 2013, 2014 Frank Sharp - You do not have permission to copy photos and words from this blog, and any content may be never used it for auctions or commercial purposes, however feel free to post anything you see here with a courtesy link back, btw a link to the original post here , is mandatory.
All posts are presented here for informative, historical and educative purposes as applicable within fair use. NOTHING HERE IS FOR SALE !

Thursday, 28 February 2019

LCD TVS. COMMON FAULTS AND REPAIRS - TROUBLESHOOTING

LCD TVs. COMMON FAULTS AND REPAIRS - Troubleshooting

       LCD TVs are todays most trend, and they are invading the electronic entertainment market, ad seems to go further. Here are some faultfinding guidelines; with you can understand the fault to your TV to an extent, provided you must have knowledge in electronics.  Sometimes, you may even repair your LCD TV too. 
Let us discuss first with its power supply section, which is more venerable to faults.
Symptom:  The LED at the front panel of the TV do not light up, even connecting the power cord and switch the TV ON.  The unit appears to be Dead condition
There is a relay connected to power supply.  It should work [when it works, you can hear a click sound can be heard after the TV is switched ON]. Listen to this click sound.
Check the status of cable connections inside the TV for any loose. Check fuses fitted with power supply regulator board and any other. Check the input voltage at the SMPS [Switched Mode Power Supply] otherwise called as power regulator board. If all these are found OK, and still the set refuses to switch ON the Relay, and no power indicator LED lights up at its front panel, make sure that the main board is faulty.  There is no repair to it by replacing components.  Replacing it is the only repair work.

Come to other possibilities.
  • Is power LED at its front panel is on and the lamp [backlight] is OFF.  If NO, check the connections of the power cable and all other cables connected to the power regulator board. If YES, does the power standby DC voltage [5VDC] is present or not.  If NO, change the main power assembly.
  • If [5VDC] is present, check the main DV voltages [13VDC].  If it is not there, check the associated capacitors, especially check the ceramic capacitors if any connected to this voltage. If there is no fault with any of the associated components, and still there is no 13VDC, the power regulator board is faulty, and should be replaced.
  • If this 13VDC is present and there is no main 120VDC present, check all the associated capacitors.  If they are also found normal. Power supply regulator board is faulty, and should be replaced.
  • If there is 120VDC is present and no 3.3VDC check the regulator IC on the main board, either for open or for loose soldering points at its terminals. Suspect the main boar assembly too in this case.
  • Check the voltages at CODEC, 3.3VDC, 8VDC & 9VDC.  If these voltages are there or not there, and the set wont switch ON, make sure that the main board is faulty.  In rare cases, a well-experienced service technician may set it right.  In 90% cases, replacement of the main board is the only remedy.
If 1.2VDC core voltage, and VCC33, VCC12, VCC25 are present, appear at FRC board and still set refuses to switch ON, the fault is not with picture circuits. Then you have to check the LCD panel
Posted By: FRANK at 02:43
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