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!

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Tuesday 19 February 2019

LG 47LG90 LED BACK LIGHT TROUBLESHOOTING

LG 47LG90 LED BACK LIGHT TROUBLESHOOTING


ENTIRE PANEL WON'T LIGHT

  1. Is the 24V being supplied to the inverters from SMPS? [CN1/CN501 pins-1-5].
  2. Is the inverter On Command arriving at both inverters? [CN 1/CN 501 pin-12] [ Main to SMPS P-201 pin-20].
  3. Disconnect the ribbon cables from the T-Con board to the inverters.  If back light turns ON, could be a T-Con problem.
1/2 THE PANEL WON'T LIGHT
  • Confirm steps 1 & 2 above for the particular inverter involved. 
  • Disconnect the ribbon cable from the T-Con board going to the particular inverter involved, could be a T-Con problem [CN8/CN9]
SECTIONS OF 1/2 THE PANEL WON'T LIGHT
  1. Locating the connection corralling that particular section should be easy.  Just compare the section that is out and align with the particular cable.
  2. Looking at the connector going to the LED back lights, look at the bottom 2 pins on 'M' inverter or the top of 2 pins of the 'S' inverter, check for 39V?  If missing, unplug the connector and recheck.  Still missing?
  3.  Using the interconnect diagram, locate the fuse protecting the 24V to the DC to DC converter that is developing the 39V for that connector.  If found open, replace the inverter.
  4. Be sure to test the back light LEDs that attach to that connector for shorted condition.  With the connector unplugged put the Red lead on the the bottom 2 pins on the 'M' inverter or top 2 pins of the 'S' driver, and the Black lead on any other 8 pins.  All should read 'open'. Or, apply 30-38V on the bottom 2 pins on the "M" inverter or top 2 pins of "S" inverter, and the ( - ) lead to any of the other 8 pins while observing that section of the panel, the LEDs should illuminate across the screen in the section controlled by that plug.
ENTIRE PANEL BACK LIGHTS ARE DIM
  • Disconnect the ribbon cables from the T-Con PWB to the inverters, could be a T-Con problem [CN8/CN9]
Posted By: FRANK at 05:53
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