Samsung LE32B350F1W BackLight problem

[budm]

Re: Samsung LE32B350F1W BackLight problem

Well, bad data can cause goose chase
So 'DET_5V = -0.009V' = you have problem in the backlights circuits, lamps per my post #15.

[dick_barton]

Re: Samsung LE32B350F1W BackLight problem

When you force OZ9938 on so that the backlights come on and stay on what voltage do you have at DET_5V. When you remove the link what voltage do you have then at DET_5V

[HellasTechn1]

Re: Samsung LE32B350F1W BackLight problem

Good Morning friends !

This case has been solved. Here is what happened.

All this time i have been trying to troubleshoot the tv with the panel assembled. I had no reason to dissasemble it since all lamps worked with the ccfl tester.
Last night i descided to take it apart and see what is going on with the lamps because i thought one of them was running a little noisy. After removing the panel and firig up all ccfl's by forceing the 0z9938 on, i realised that the bottom lamp would not turn on at all...
While surprised by that, i took out the lamp and re tested it and again found it in perfect condition (not even black at the edge).
I started suspecting the corresponding trenasformer and then i removed it and measured it and found it good.
I descided to swap the transformers to see what happens and when i did then the problem was carryed to the second lamp.

Conclusion : though it gives correct Ohm readings the transformer is bad ! I can not really explain it but it is...

I will order a new one and after i get it i will post back the resault though i am now 100% sure that this is what triggers the protection and shuts down the lamps.

[dick_barton]

Re: Samsung LE32B350F1W BackLight problem

Interesting. Keep us posted.

[HellasTechn1]

Re: Samsung LE32B350F1W BackLight problem

Note that with protection disabled the bad transformer will only turn on one of the two connected lamps while it overheats at the same time and smells burned.

[HellasTechn1]

Re: Samsung LE32B350F1W BackLight problem

I will write back as soon as i get the new transformer in about 30 days or so.

I have to say that every time i come across a problem with a TV, i am for some reason 100% sure that you will help me figure it out and eventually fix it !

It is not only the provided help but also the experience i gain thanks to you !

Thank you for everything friends!

[HellasTechn1]

Re: Samsung LE32B350F1W BackLight problem

I received the transformer afew days ago and installed it on the board.
Problem fixed.

Tank you all for hellping me out !

Happy new year to you !

[sshady]

Re: Samsung LE32B350F1W BackLight problem

Now this is interesting !

i was looking at the OZ9938 datasheet and i thought to myself, why dont i try to disable protection just to see if the ccfl's will keep on !
So i shorted pin 3 between the resistor and the capacitor to pin 16 and it worked.
The ccfl's winn not go off.

That confuses me further because the lamps are good, i have tested them one by one with a ccfl tester and they are all glowing.

Thank you for the information. I have same Tv and same issue. one of the ccfl lamb not workin and its going the protection. i have tested ccfl's, tried new ones still nothing change. also i couldnt found the issue on inverter board. Now i try to disable protection just like you shared and it worked. Still one ccfl is not working but the others work fine and not goes off. Thanks again