LG 42PJ350 42 in. TV - Answered Questions & Fixed issues

Back - light problem. Check and replace damaged component/s at its back-light inverter board, or replace this board as card basis. If you wish to get some details; check the site linked here. Surf the site with patience. Pull up older posts. It will be best to replace the inverter board as card basis. http://electro-medical.blogspot.com/ http://electronicshelponline.blogspot.com/ To some model sets; especially LED back-lighted types; the back-light inverter circuit will be part of the main power supply board [SMPS]. In such cases, the power supply board might need replacement. To some models sets, the back-light inverter and SMPS section circuit will be integrated at its main board itself. If so; the main board should be replaced. To some models of sets, all these section circuit will be integrated at its main board. If this is the case, you have to replace the main board.

Fault to the main power supply regulator section. Either it will be on a separate board, or on the part of its main board. Check and replace damaged component/s at its main power regulator [SMPS] section circuit. Contact any service technician. If you wish to get some details; check the site linked here. Surf the site with patience. Pull up older posts. http://electronicshelponline.blogspot.com/ It will be best to replace the power supply regulator board as card basis rather than making "Surgery" to it; which usually will make loss for both money and time. Even though you can make it right, it will cost around an amount equal to the cost of a new board; including the cost of (spare parts + service charge) More to say, most of the spare parts to it will be difficult to get from open electronic spare part market. This is true to most of the flat panel TV power supply boards; irrespective of its brand and screen size.

USB 2.0 is only for MP3 and JPEG. Up to my knowledge, your TV has no bluetooth connection and it is not a Smart TV, So, unless my information about this tv is not complete, there is no way to connect it any dongle. You can connect it to your computer through the HDMI cable: or if it has it, tha VGA input from PC. LG 42PJ350 Specifications Page 2

Fault with the main power supply regulator board. Check and replace damaged component/s at its main power regulator [SMPS] section circuit. Contact any service technician. If you wish to get some details; check the site linked here. Surf the site with patience. Pull up older posts. http://electronicshelponline.blogspot.com/ It will be best to replace the power supply regulator board as card basis rather than making "Surgery" to it; which usually will make loss for both money and time. Even though you can make it right, it will cost around an amount equal to the cost of a new board; including the cost of (spare parts + service charge) More to say, most of the spare parts to it will be difficult to get from open electronic spare part market. This is true to most of the flat panel TV power supply boards; irrespective of its brand and screen size.

Check the speaker/s first. If found OK; check and replace the damaged component/s at its audio output section circuit board. If needy, replace this board as card basis. If you wish to get some details; check the site linked here. Viewing it in "Mosaic" or "Magazine" will make surf easy. Surf the site with patience. Pull up older posts. Surf the site with patience. Do a search by type in the brand name of your device at its search box. http://electronicshelponline.blogspot.com/

Sounds like a bad power supply if you have a volt meter you'd want to take off the back of the tv and test the power supply with the volt meter to see if it's getting a constant power supply or if it is intermittent if it is call LG if it's under warranty and have them fix it if not look online for a new power supply and replace it and then you'll be good to go!

There is no backlight CCFL lamps to plasma dispays.

Check and replace the back-light inverter board.

The back-light inverter board should be checked and replaced. It is faulty. Check this link, if you wish to get for more details.

Look on your remote and see if it has an aspect button if does press until you get it back to A normal screen

1176 mapped the most buttons for me.

Yes, life span on Plasma and LCD sets is 3-5 years.The green line (or any line) can be a board (sustain types on Plasma or inverter on LCD) but can even be a control problem inside the set--area that controls scanning etc) and in worst case can be the display panel itself--fatal issue.Trouble shooting entails a signal generator, a expensive scope, and a good set of hands working with them to check voltage, waveforms, etc to try to decide where the problem is.Then we have the board jockeys who guess and try one board after another (gets expensive and takes time) to see which if any board will fix the problem---when all boards have been tried (seen this ) all that is left is the panel or display unit--cost for that is more than the set new.

Hello,The issue you describe is consistent with a power supply board issue. This is the board where the AC goes to. This problem may have occurred as a result of irregular power supply, or excess power supply or power surge.The TV is receiving current but cannot circulate or transfer the current to other necessary part of the TV because of the defective power supply board. You might be lucky it's just a blow fuse. Also a defective transformer can cause your TV not to power on.All these can be checked on the power supply board.But more often bad capacitors causes problem on the power supply board. I do not think the power board needs replacement, rather those defective capacitors is causing this issue. Open unit up and take a look at the power supply board.You will probably see one or more electrolytic filter capacitors that are bulged up in the top-not perfectly flat like the others.The value of these capacitors will be different, most likely they will be somewhere around-820 to 2200uF/25 V( or /10V sometimes)You can replace them with same values but I would recommend the voltage rating to be higher(like 35V for an original 25V) for reliability purposes.What happens is,these bulged top capacitors will cause a low and unfiltered DC voltage=main board will malfunction(the relay will keep clicking until the caps are holding enough charge to bring the voltage up over a threshold point).You can buy these capacitors at any Fry's or Radioshack store or you can order them online at vendors like "mcmelectronics.com"(look for electrolytic capacitors). After replacing these capacitor(capacitors) most likely the normal operation will be restored. Or you can by a refurbished complete power board to save you some stress.Note: There may be also some other causes for this symptom ,like a defective T con board ,or main board,but the bulged top capacitors are the most common cause for this issue.If you don't know about TV repairers, take the TV to the nearest repairman to fix the fault for you. Also, note that TV stores a lot of current, so wait a while before opening the TV back cover.I hope this helps.Good luck.

it sounds like you have some bad caps on the power board

Not worth replacing the screen as the cost seems a huge factor . Also taking into consideration that you need to get this part delivered with insurance , along with the freight it might not be worth the RISK. Also after spending this much you still sont enjoy any warranty. I prefer that you scrap the TV ,might get some amount for the working bboards and go in for a new model with improved features.Try for any exchange schemes from dealers.Thank you for using fixya.

TRY THIS LINK
http://www.amazon.co.uk/LG-42PJ350-42-inch-Widescreen-Freeview/dp/B003G2DJ3E

Good day!


If your TV doesn't have any indicator lights (LED) on the front of your TV. That problem is no longer connected to the firmware.

That problem is usually happen when the power supply failed.

Just follow this step on how to fix that problem.

1. Remove the back cover.
2. Try to look at the power supply board.
3. Plug-in the TV and power it on again to perform a voltage data.
4. Then check the input voltage of the power supply it should have 110vac or 220vac using multimeter (range on AC).If none the power cord is broken,replaced it.
5. If you have input voltage next is to check the output voltage of the power supply board.It should have 5vdc for the system board or main board,12vdc for the audio and 24vdc for the inverter board (back-light)using multimeter (range on DC).
   
6. If you don't have a output voltage please check the following parts:

• Fuse---------Check if it is busted or blown.
• Transistor-------Check if it is shorted using multimeter (range in Diode test).It should have no reading on reverse testing.
• Resistor--------Check if it is open or change value using multimeter (range on Ohms).
• Capacitor------Look at the actual image of it.If it is leak or bulged on the top.

If you found any of the defects parts like on the mention above.Please replaced it with same type,ratings and value.

If you have replaced the defective parts and the problem is still there.The power supply board could be got a major trouble or damaged.If it is happen your choice is to send it to the nearest service center or you buy a new power supply board.
Just click this site to order a new power supply board.

http://www.hotpriceparts.com/servlet/the-4360/LG-42PJ350-POWER-SUPPLY/Detail

I hope this solution will be helpful.thanks for using fixya.

You cannot reverse it. Some other manufactures if this happened, you could reinstall old firmware, but not on LG. You must replace your Main PCB

its very simple try to cleck the restore or go to the menu setting or make sure its not in video mode.god bless

Hi doubles,
Power on the unit in the dark room then shine with the flashlight directly in the screen, you will barely see the images. This is because your backlight is not functioning. The following reason is the caused.
1. Power supply - missing B+(supply voltage) coming from this board feeding the inverter board. This is caused by faulty transistor, dried/leaky electrolytic capacitor, open fusible resistor.
2. Inverter board - even the B+ is good from the power supply, if the fuse, driver transistor, driver transformer is faulty no output to the backlight resulting to black picture.
3. Busted backlight - even inverter board is good but if this is busted resulting to black picture also.
Diagnosing the fault is technical and if you don't have necessary tools and test instrument and can't fix it yourself, I would advice you to look for an experienced technician to isolate the problem.
Hope I helped you.
Have a nice day!
Thanks for using Fixya.