Samsung LN40B530p7 sound ok picture inop

[MLOO55]

I Have a problem with this tv, it happens that when I turn on the picture is normal but after 10 sec it turns black but sound or other functions work fine.
I checked all caps with an esr tester and a cap tester so no cap damage was found.
The voltage at the two main filter are:
tv on 380 volts tv off 290 volts.
Checked for any other component damaged ,resistors,diodes,mosfet and at first sight found none.
As you can see in the picture where the connector is I took the voltages when the tv is on is as follow:
1 3.17 v 16 5.22 v
2 2.59 v 17,18 0 v
3 5.2 v 19 13 v
4 , 5, 6 0 v 20 0 v
7,8 13 v 21,22 13 v
9,10,11,12 0 v 23 4.46v13,14,15 5.22v 24 0 v
25 3.34
26,27,28,29, 30 0v
I have some doubt about the reading at pin 23 inverter on/off, is this voltage correct? Besides at pin 25 what signal is E-pwm? and finally at pin 27 I have all the time 0v.
I will appreciatte your comments about this problem or could be the lamps or one of them?
rgds
mloo55

[MLOO55]

Re: Samsung LN40B530p7 sound ok picture inop

Copying again the reading of voltages at connector CN801:
1 3.17
2 2.59
3 5.2
4,5,6 0
7,8 13
9,10,11,12 0
13,14,15,16 5.2
17,18 0
19 13
20 0
21,22 13
23 4.46
24 0
25 3.34
26,27,28,29,30 0

At pin 27 DET_5v voltage is 0 v? is correct
thanks
mloo55

[budm]

Re: Samsung LN40B530p7 sound ok picture inop

Please put the names of each pin after the pin number so we can see what Voltages, signals are missing.

[johnboy1313]

Re: Samsung LN40B530p7 sound ok picture inop

It looks like this is PSU BN44-00264B, but I can't tell for sure. Check for cold solder joints/burn marks at the inverter transformers. It's also posible you have a bad CCFL, or more, inside the panel.

[budm]

Re: Samsung LN40B530p7 sound ok picture inop

Pictures are not well focused to read the board P/N, BN44-??????
I suspect bad inverter transformer as well.

[MLOO55]

Re: Samsung LN40B530p7 sound ok picture inop

Here are the name of each pin and voltage with tv on and effectively the board is BN44-0264B.
1 3.17 ON/OFF
2 2.59 H_sync
3 5.2 5VSB
4,5,6 0 GND
7,8 13 13V
9,10,11,12 0 GND
13,14,15,16 5.2 5.3V
17,18 0 GND
19 13 13V(MAIN)
20 0 GND
21,22 13 13V(mAIN)
23 4.46 INVERTER ON/OFF
24 0 NC
25 3.34 E_PWM
26 0 GND
27 0 DET_5V
28,29,30 0 GND

thanks for your help
mloo55

[budm]

Re: Samsung LN40B530p7 sound ok picture inop

It has all the correct Voltages and signals, so did you look real close at the inverter transformers to see if one or more of them has a sign of over heated, you need to look at both sides of the board.
You also need to check the resistance of the HIGH vOLTAGE Winding of the inverter transformers to see if one or more than one have bad readings.
BN44-00264B
https://www.badcaps.net/forum/showth...ht=bn44-00264b

http://www.shopjimmy.com/qgah02095-i...ansformer.htm#
http://www.shopjimmy.com/samsung-bn4...wer-supply.htm

[orinoco8]

Re: Samsung LN40B530p7 sound ok picture inop

You may want to check INVERTER ON/OFF voltage before and after the 10-second shut-off of backlight.

[POL UK]

Re: Samsung LN40B530p7 sound ok picture inop

Renew all 1000uF SMD capaccitors in PSU. Best Reagards

[MLOO55]

Re: Samsung LN40B530p7 sound ok picture inop

I checked all inverter transformer and no signos of spots por something like it, all hace the same resistance readings.
The voltage at the on/off inverter pin is the same all the time as the tv is connected to the outlet.
I resoldered several points but the problem continúe. By the way, I have not replaced any ñamp until this momento mayor you indicate the steps to reach the lamps forma this tv.
Thanks
Mloo55

[johnboy1313]

Re: Samsung LN40B530p7 sound ok picture inop

I'm betting you have a bulb that is failing or has already failed. Open the panel and take a look.

[MLOO55]

Re: Samsung LN40B530p7 sound ok picture inop

I need your help for this task, how to reach the lámps? I removed the back cover and found the two boards so can you letra me Know what is the next Step or Steps.
Rgds
Mloo55

[johnboy1313]

Re: Samsung LN40B530p7 sound ok picture inop

You'll need to remove the plastic frame from around the panel. This will expose a metal frame surrounding the screen. Remove all of the screws holding the metal frame on. Remove the metal frame. Carefully lift the screen and store it flat, away from any chances of being broken. You will then see another plastic frame that will need to be removed. Then remove all of the diffuser sheets. Keep them all in order. They need to go back in the way they came out. This will expose the lamps.

[MLOO55]

Re: Samsung LN40B530p7 sound ok picture inop

John, it means i have to remove the black bezzel which in the front so i can reach the lamps by this side no from he back,is correcta?
Thanks

[johnboy1313]

Re: Samsung LN40B530p7 sound ok picture inop

Correct, you'll have to go in from the front.

[MLOO55]

Re: Samsung LN40B530p7 sound ok picture inop

John,
I disassembled the tv to reach the lamps, followed your instructions and found some of the lamps are worn out so I will buy them to replace . They are 35.5 inches long. Again thanks.
mloo55

[ReeceyBurger123]

Re: Samsung LN40B530p7 sound ok picture inop

By a smashed 40" version off ebay and salvage the lamps.

[MLOO55]

Re: Samsung LN40B530p7 sound ok picture inop

Thanks Reecey, goog info

[bold_fusion]

Re: Samsung LN40B530p7 sound ok picture inop

Hi there,

I have an identical initial symptom (sound ok picture blinking off/on). The issue goes away when I turn the Backlight all the way to 0/10, but every so often the Backlight setting seems to automatically "reset" to 10/10 :-\.

Thanks to this thread and forum, and a pair of YouTube posts (big thanks to https://www.youtube.com/watch?v=Dh01ZepjDp0 and https://www.youtube.com/watch?v=PflyJ4H51Fg), I've heard 3 main possibilities for this type of symptom:

1. Inverter board caps bad (e.g., bulging?)

2. Inverter board transformers bad (e.g., burn marks?)

3. Back-light CCFP lamps bad

Re #1, I don't see any caps bulging, but should I nonetheless test all the ceramic and electrolytic caps on the board?

Re: #2, I don't see any burn marks on the inverter transformers, but didn't check the bottom side of the board. With the board unplugged, should I measure the resistance across both the primary and secondary windings on each of the 4 CCFP-driving transformers, and could you say what a "health" value would be?

Re: #3, the video https://www.youtube.com/watch?v=Dh01ZepjDp0 is for a slightly different board, but shows how the "primary" of the transformer driving a broken CCFP lamp can be "bypassed" so that the low-resistance lamp isn't driven any more. This would make that lamp dark, but at least it would mean that the display wasn't turning off and on repeatedly. (I would gladly take that solution for the moment, and figure out how to repair the screen later!). For the inverter board of this thread (BN44-00264B), would the above bypass be feasible as a short-term solution, or would that, ahem, be a bad idea?

[nomoresonys]

Re: Samsung LN40B530p7 sound ok picture inop

That's a good video there, watch closely how he does the ground out test, if you do that and the tv stays on then you found the problem and the bypass will work.