samsung ln40b530p7fxza light up problem

[gmzombie]

OK i received this TV and it only has sound. you can hear the system play anything as such i plugged in a Xbox to the hdmi and it was playing the game but it didn't have any back light. i checked the voltage to the man board from the all in 1 power supply inverter but im not sure where i should check for the backlight side. ive got the board out and everything looks good at least no burnt traces or anything. both fuses are fine it just seems like the high voltage side is not working? any suggestions?

[PlainBill]

Re: samsung ln40b530p7fxza light up problem

OK i received this TV and it only has sound. you can hear the system play anything as such i plugged in a Xbox to the hdmi and it was playing the game but it didn't have any back light. i checked the voltage to the man board from the all in 1 power supply inverter but im not sure where i should check for the backlight side. ive got the board out and everything looks good at least no burnt traces or anything. both fuses are fine it just seems like the high voltage side is not working? any suggestions?

Yes, quite a few.

1. Review your composition classes. Proper capitalization and spelling structure assist in comprehension by the reader. Breaking it into short paragraphs also help.

2. Pictures are a great help. I suggest starting with a single over-all picture of the back side of the TV (with back removed, of course). This allows identification of interconnections between various boards.

3. When listing a model number, do so exactly as printed on the label. The base model number in this case is LN40B530. The service manual is here. Unfortunately, most service manuals do not include the inverter.

PlainBill

[fastvideo]

Re: samsung ln40b530p7fxza light up problem

https://www.badcaps.net/forum/showthread.php?t=14644

Check here, should be the same power and inverter circuit.

[gmzombie]

Re: samsung ln40b530p7fxza light up problem

OK to update here are some pics of the whole backside of the TV. Then i took 3 pics of the power supply board, A whole pic, a left half, and a right half. There is also a pic of the main board, and the tcon board.
I have verified that if you put a flashlight behind the LCD it does in fact show a picture. I have checked all the diodes in the board and they all show a rating on one side and infinite on the other just as they should.
I thought i had the right model code but it seems to be this Samsung ln40b530p7f. Hopefully this helps out so i can get this diagnosed and repaired.

Also i tried to download the service manual but it wouldn't let me. it said 2 downloads per guest per day. I'm using Firefox so that isn't the issue.

[truep]

Re: samsung ln40b530p7fxza light up problem

Do you have 24V going to the inverter from the power supply?

[gmzombie]

Re: samsung ln40b530p7fxza light up problem

being that the inverter is on the power supply board im not quite sure where to check for the 24v.

[PlainBill]

Re: samsung ln40b530p7fxza light up problem

OK to update here are some pics of the whole backside of the TV. Then i took 3 pics of the power supply board, A whole pic, a left half, and a right half. There is also a pic of the main board, and the tcon board.
I have verified that if you put a flashlight behind the LCD it does in fact show a picture. I have checked all the diodes in the board and they all show a rating on one side and infinite on the other just as they should.
I thought i had the right model code but it seems to be this Samsung ln40b530p7f. Hopefully this helps out so i can get this diagnosed and repaired.

Also i tried to download the service manual but it wouldn't let me. it said 2 downloads per guest per day. I'm using Firefox so that isn't the issue.

Well, I've seen better pictures, but these give plenty of information. If you make them just under 2000 x 2000 pixels we can get more information. The design has gotten a lot simpler in the past 5 years.

Points to check:

1. It may be necessary to register on Elektrotanya. It's a free registration and I haven't been spammed as a result, so it should be safe.

2. Refer to the last picture. Above and to the left of the bar code label is the pinout of the output connector. Check the voltages.

3. Note the transformer bottom center of the same picture. Is that scorched or is that dust? If it's scorched, QGAH02095 is available on eBay.

4. Pictures of the bottom of the inverter will help troubleshooting if the brown spot is dust.

PlainBill

[gmzombie]

Re: samsung ln40b530p7fxza light up problem

1. i tried this and it said it was for invite only.

2. i checked the pinout output voltages and they all seem to be in spec. 13v was at 13 5.3v was like 5.32v and whatnot.

3. it is not dust that is for sure. so im assuming that it is scorched but is there a better way to tell.

4. I will have to get you a picture of the back side of the power supply board tomorrow. its late now.

[PlainBill]

Re: samsung ln40b530p7fxza light up problem

1. i tried this and it said it was for invite only.

2. i checked the pinout output voltages and they all seem to be in spec. 13v was at 13 5.3v was like 5.32v and whatnot.

3. it is not dust that is for sure. so im assuming that it is scorched but is there a better way to tell.

4. I will have to get you a picture of the back side of the power supply board tomorrow. its late now.

1. I'll check that out.

2. Good

3. Compare the resistances of the secondaries

4. Whatever.

PlainBill

[gmzombie]

Re: samsung ln40b530p7fxza light up problem

ok i hope i did this correctly

i took measurements on both sides of those qgah02095 and on all 4 of them

first one closest to power plug
side of light plugs 3 is the scorched one
(1.)1.19k /1.18k (2.)1.19k/1.18k(3.) .955k /8.3mega (4.)o/l / 1.2k ohm

other side of qga's
(1.) .1/.1 (2.)1.8/1.9 (3.).1/1.9 (4.).1/1.9

Also did you figure out the register for that site?

[PlainBill]

Re: samsung ln40b530p7fxza light up problem

ok i hope i did this correctly

i took measurements on both sides of those qgah02095 and on all 4 of them

first one closest to power plug
side of light plugs 3 is the scorched one
(1.)1.19k /1.18k (2.)1.19k/1.18k(3.) .955k /8.3mega (4.)o/l / 1.2k ohm

other side of qga's
(1.) .1/.1 (2.)1.8/1.9 (3.).1/1.9 (4.).1/1.9

Also did you figure out the register for that site?

I'm going to make an assumption here. I suspect there was flux or something else coating the pins of the transformer, that is why one end of 4 reads open. You might want to verify that. One secondary winding on transformer 3 is significantly (20%) lower than the others. Replace transformer 3. If you cannot get comparable readings (1.2K +- 3%) on transformer 4, replace it also.

No, I haven't. I've been goofing off.

PlainBill

[Village Electronics]

Re: samsung ln40b530p7fxza light up problem

No, I haven't. I've been goofing off.

PlainBill

Don't sass the customers Bill or you're going to get a cut in pay.

[PlainBill]

Re: samsung ln40b530p7fxza light up problem

Don't sass the customers Bill or you're going to get a cut in pay.

You can't cut my pay, I QUIT!!!!

PlainBill

[PlainBill]

Re: samsung ln40b530p7fxza light up problem

Also did you figure out the register for that site?

Well, sort of. I haven't figured out how to issue an invitation, but an invitation isn't necessary.

Here's what you or anyone else must do.

1. Go to Elektrotanya.

2. In the left hand Navigation menu click on About Site

3. Click on fill up an electricity test.

4. On the next page enter your email address

5. Then answer 5 simple electronics questions.

PlainBill

[Dgtech]

Re: samsung ln40b530p7fxza light up problem

Well, sort of. I haven't figured out how to issue an invitation, but an invitation isn't necessary.

Here's what you or anyone else must do.

1. Go to Elektrotanya.

2. In the left hand Navigation menu click on About Site

3. Click on fill up an electricity test.

4. On the next page enter your email address

5. Then answer 5 simple electronics questions.

PlainBill

Step #6. Insert five euro's into the slot.

[PlainBill]

Re: samsung ln40b530p7fxza light up problem

Step #6. Insert five euro's into the slot.

That's only required of smart alecs.

PlainBill

[gmzombie]

Re: samsung ln40b530p7fxza light up problem

just to update replacing both inverter transformers fixed the tv. it now turns on and i can see it again.. thanks for your help.

[PlainBill]

Re: samsung ln40b530p7fxza light up problem

just to update replacing both inverter transformers fixed the tv. it now turns on and i can see it again.. thanks for your help.

Glad to hear you have it working.

PlainBill

[cre3]

Re: samsung ln40b530p7fxza light up problem

Thanks for sharing and your help.

I had the same problem on the same tv. Screen turns off and on. No problem with the sound.
So I saw this forum and dissassemble my tv and have seen the damaged transformer.

First I bring the board only to a "tv repair". They wanted to have the all tv and replaced the entire board for 250$ and keep the old one. They cannot put a new transformer.

I said no and order a new part on ebay (+ a soldering iron in my city) and put the new transformer.

The tv works now pretty well like before. Good for watching "rugby world cup"

sorry for my english and thanks again!

[Horty24]

Re: samsung ln40b530p7fxza light up problem

I also have a burned transformer. Is there any thing I should be careful so I dont get shocked? My tv turns for 2 seconds and off for 4 seconds.