Re: Samsung LN40A550P3FXZA video not working



Is this an indication of anything? I have been trying to find a wiring diagram to see what each capacitor is supposed to be there for.



Ever since the first message in this thread I've run the TV with the back off. The temperature in the room is between 72F and 76F (22C to 24.5C). Today I left the TV on for about 4 hours on HDMI with no problems (with video playing the whole time). After that, I switched to cable and changed channels for like 5 minute at least until it finally failed and the...

Re: Samsung LN40A550P3FXZA video not working

Hi,

Here is as a comprehensive set of measurements as I could put together:

CN801 pin #1 POWER ON/OFF: Before 4.3, After 4.31
CN801 pin #2 SYNC: Before 1.654, After 1.652
CN801 pin #3 STB5.3V: Before 5.08, After 5.08
CN801 pin #4 GND: Before N/A, After N/A
CN801 pin #5 GND: Before N/A, After N/A
CN801 pin #6 GND: Before N/A, After N/A
CN801 pin #7 13V: Before 12.84, After 12.86
CN801 pin #8 13V: Before 12.85, After 12.85
CN801 pin #9 GND: Before N/A,...

Re: Samsung LN40A550P3FXZA video not working

Hi,

Well, quick update on status. I have it connected only to HDMI and cable. The HDMI works fine for some time (I have not left it too long, but it will go easily for 5 minutes). However, once I put it on cable, it will only last a couple seconds until the video goes out. Then I have to wait at least some 5 minutes to turn it back on. I made short video of this (music video is plating through HDMI from my computer ): [url]https://www.youtube.com/watch?v=0oJTzEiKsYM[/url]

CapLeaker: This is what I have...

Re: Samsung LN40A550P3FXZA video not working



Before failure 9.82 VDC. After Failure 10.08 VDC

Both pins labeled LD



Before failure ~0.190 VAC. After Failure 0 VAC

Both pins labeled FB



Fixing all these solders might be a bit too much for my soldering skills. But just out of curiosity, how would you go around fixing these properly?

Again, thank you so much for your help budm!

SEBA...

Re: Samsung LN40A550P3FXZA video not working

Hi again. Here's the update:

- Backlights: They do turn off when it fails.

- Solder joints: Everything looks pretty great. I took some pictures of the back of the power supply board. Now it is confirmed these are not the original capacitors. You can see where they were soldered (not the best job, but they are connected)

- BL-ON pin: I am still not sure which pin this is on the board. I did measure:
CN801, pin #1: 4.31 VDC before and after the failure.
CNI803, pin #1: 4.91 VDC...

Re: Samsung LN40A550P3FXZA video not working

Hi guys! Thanks for the replies. I am at work, so I'll be able to check all this tonight However, in the meantime, I have some extra questions as I am not very familiar with the terminology:



- The backlights refers to the white light you see from the back of the screen? If so, I am almost positive they do go out but will confirm later. If that is not what you were talking about, please let me know.

- Solder joints on the power supply board... The line voltage goes to a small plug on the lower...

Hello,

I have a LN40A550P3FXZA. When you turn the TV on, everything works perfectly. Then, after maybe 5 minutes or as long as 2 hours or whatever time (not regular), the screen goes completely off (no glare, no stripes, nothing, just like if it was off), but the audio keeps going. Turning it off and back on works very rarely. Most of the time I need to let it sit for a couple of minutes at least. And when I turn it back on, it happens again. One thing I've noticed is that the failure occurs faster if I am watching cable (directly connected to the back, no box), and even faster...

Re: Samsung LN40A550P3FXZA video issues

Hello,

I have the exact same problem as described by darkweezil.

I have a LN40A550P3FXZA. When you turn the TV on, everything works perfectly. Then, after maybe 5 minutes or 2 hours or whatever time (not regular), the screen goes completely off (no glare, no stripes, nothing, just like if it was off), but the audio keeps going. Turning it off and back on works very rarely. Most of the time I need to let it sit for a couple of minutes at least. And when I turn it back on, it happens again. One thing I've noticed...