lg 32LC46 backlight inverter board fault

[jimbofz]

Re: lg 32LC46 backlight inverter board fault

that's probably the forum's auto resizer.

So you must have an inverter fault, there is no way all the lamps aged uniformly and got darker on one side.

What's the voltage on error, on/off, i-pwm and e-pwm?

One of these pwm voltages controls the lamp brightness, if this is the same as other old lg lcds, 3.3v should be maximum brightness, and less than 0.8v it doesn't even turn on.

These wires that you used for bypassing the error pin, they're too long, try using the least amount of wire you can, if nothing changes, i suggest replacing the inverter board, it's cheap at least.

e pwm =4.1v i pwm= 3.3v on/off=4.9v error =0v

[jimbofz]

Re: lg 32LC46 backlight inverter board fault

replacing board ? wheres the fun in that ,
this tv is only worth peanuts due to its age
but i enjoy the challenge of fault finding down to component level .
its the best way to learn
and this tv despite its age ic capable of good clear hd pics
seasons greetings to all

[Biruslapio]

Re: lg 32LC46 backlight inverter board fault

The voltages sent from main board are correct, it is the inverter that is at fault, maybe even a replacement board costing around 7 USD is not worth it on UK? Plus there's shipping.

What about those 0 OHM resistors, are they fine? There should be no voltage drop on any of them, not much else to suggest here.

[jimbofz]

Re: lg 32LC46 backlight inverter board fault

The voltages sent from main board are correct, it is the inverter that is at fault, maybe even a replacement board costing around 7 USD is not worth it on UK? Plus there's shipping.

What about those 0 OHM resistors, are they fine? There should be no voltage drop on any of them, not much else to suggest here.

thanks for trying all zero ohm components checked
still a work in progress ,i will post the results

[jimbofz]

Re: lg 32LC46 backlight inverter board fault

finally fixed inverter board fault
47 ohm r76 was o/c causing shading left to right
its across d12

[dick_barton]

Re: lg 32LC46 backlight inverter board fault

Well done. Persistance paid off.

[jimbofz]

Re: lg 32LC46 backlight inverter board fault

Well done. Persistance paid off.

im like a dog with a bone

[dskall]

Re: lg 32LC46 backlight inverter board fault

im like a dog with a bone

Well, it's good you didn't bury it and just keep gnawing on it.