Samsung LCD TV Black Screen (Weird!)

[HerculesDK]

Dear Board of AV experts and enthusiasts,

I have a Samsung LCD LE40A856 Full HD TV, which I bought in 2009. The TV has been working fine, but I noticed that there was a line down in the left side of the panel, when I did a cold boot up that disappeared after 10 minutes or so. This was not really an issue, but then I moved and have not used the TV for long. The times when I did turn it on it worked fine. But for some weeks ago I had to connect my PS3 to the TV using the HDMI port and it started to act funny. It just showed a black screen when I tried finding the PS3 and started to freeze in the menu. But the TV signal was fine. The freezing got worse and the TV started to operate very slowly so I switched the TV off. Since then it clicked a few times with a black screen and I haven't been able to test the sound. The panel sounds work, but there is nothing on the display. This is what I have tried so far:

1) Checking the capacitors – I couldn't find any faulty ones, but I changed them all on the power supply.

2) Checked and changed the two 450v 68uf ones also even though they looked fine.

After doing the above mentioned the situation is the same. I am starting to suspect that it might be the T-con board or the main board; however I do not have the means to test these. I did notice today that before resetting (it is in a kinda boot loop) the LCD TV does light op before shutting down. So I do not think that the panel is dead, which is good news (if I am right). The TV only clicks once on startup and nothing else. However, I noticed that the volume up touch sensitive button on the TV set on the front is blinking all the time. I've tried calling Samsung, but they did not know what it meant! I do believe that this is some kind of a diagnostic problem indicator, which I do not know the meaning of.
Is there anyone that can help me with my Samsung LCD TV set? The TV is unplugged at the moment, but I wish I somehow could reset the BIOS/firmware or the eeprom or so. It does have a Service port, but I don't know how to use it? It also has an Ethernet port, but I don't know how to use it in this situation.

I am in desperate need for help and guidance,

Yours truly,

/D

[killian6pk]

Re: Samsung LCD TV Black Screen (Weird!)

Dear Board of AV experts and enthusiasts,

I have a Samsung LCD LE40A856 Full HD TV, which I bought in 2009. The TV has been working fine, but I noticed that there was a line down in the left side of the panel, when I did a cold boot up that disappeared after 10 minutes or so. This was not really an issue, but then I moved and have not used the TV for long. The times when I did turn it on it worked fine. But for some weeks ago I had to connect my PS3 to the TV using the HDMI port and it started to act funny. It just showed a black screen when I tried finding the PS3 and started to freeze in the menu. But the TV signal was fine. The freezing got worse and the TV started to operate very slowly so I switched the TV off. Since then it clicked a few times with a black screen and I haven’t been able to test the sound. The panel sounds work, but there is nothing on the display. This is what I have tried so far:

1) Checking the capacitors – I couldn’t find any faulty ones, but I changed them all on the power supply.

2) Checked and changed the two 450v 68uf ones also even though they looked fine.

After doing the above mentioned the situation is the same. I am starting to suspect that it might be the T-con board or the main board; however I do not have the means to test these. I did notice today that before resetting (it is in a kinda boot loop) the LCD TV does light op before shutting down. So I do not think that the panel is dead, which is good news (if I am right). The TV only clicks once on startup and nothing else. However, I noticed that the volume up touch sensitive button on the TV set on the front is blinking all the time. I’ve tried calling Samsung, but they did not know what it meant! I do believe that this is some kind of a diagnostic problem indicator, which I do not know the meaning of.
Is there anyone that can help me with my Samsung LCD TV set? The TV is unplugged at the moment, but I wish I somehow could reset the BIOS/firmware or the eeprom or so. It does have a Service port, but I don’t know how to use it? It also has an Ethernet port, but I don’t know how to use it in this situation.

I am in desperate need for help and guidance,

Yours truly,

/D

Take good clear focused pictures of (1) All boards connected as if you just took the back off. (2) Top and bottom of each board. No larger than 2000 x 2000 dpi. Try to use natural light not flash. We want to be able to read the printing on the boards. Use the Manage Attachments button below to load your pictures. If you don't see it use the Go Advanced Button and scroll down and you will see it. Also you mentioned not having the means to test these boards. By that do you mean that you don't have a multimeter?
One last thing. Post the brand and series of caps that you used to replaced yours. How did you determine if they were faulty or not?

[HerculesDK]

Re: Samsung LCD TV Black Screen (Weird!)

Take good clear focused pictures of (1) All boards connected as if you just took the back off. (2) Top and bottom of each board. No larger than 2000 x 2000 dpi. Try to use natural light not flash. We want to be able to read the printing on the boards. Use the Manage Attachments button below to load your pictures. If you don't see it use the Go Advanced Button and scroll down and you will see it. Also you mentioned not having the means to test these boards. By that do you mean that you don't have a multimeter?
One last thing. Post the brand and series of caps that you used to replaced yours. How did you determine if they were faulty or not?

Thank you for your reply! I've created a PDF file with all the pictures that you've asked for. Please notice that I done the following things so far:

1) Changed capacitors – small ones and two big ones on the power supply.
2) Created two “bridges” on the T-con board to see whether it was those fuses that needed to be changed.
3) I do not have a multimeter to check things; however, I had the fuses checked on the power board by an electronic shop (only three).

I dont even think any of them were faulty. I spoke to a guy in the electronic shop, where I bought them and he and the electrician came to the same conclusion as me that they probably weren't faulty. But I changed them all just to be safe.

I hope to hear from you soon and hope that someone can help me please.

Link:

http://www.filefactory.com/file/6ixh..._w_Remarks_pdf

PS.: I suspect that there might be some kind of short circuit, but I am not sure.

[HerculesDK]

Re: Samsung LCD TV Black Screen (Weird!)

Also the 4th button from the right - the volume up button (+) is blinking all the time. Does anyone know what this means?

[tom66]

Re: Samsung LCD TV Black Screen (Weird!)

Hmm. Maybe the TV is getting into a weird mode because the touch panel buttons appear stuck to it? If you unplug the console button panel does it still give issues?

[HerculesDK]

Re: Samsung LCD TV Black Screen (Weird!)

Hmm. Maybe the TV is getting into a weird mode because the touch panel buttons appear stuck to it? If you unplug the console button panel does it still give issues?

Hi Tom and thank you for your reply.

I've just tested your theory and the result is the same, but this time just without the blinking lights

However, I tried starting the LCD TV without plugging in the cable for the T-con board and now the source button on the touch screen panel is blinking instead of the 4th button. Which makes me think 2 things:

1) its either the mainboard - a short circuit in that
2) or the T-con board, but I cant see any "problems" with it? Any marks or so.

Thank you for your help :-)

[HerculesDK]

Re: Samsung LCD TV Black Screen (Weird!)

Perhaps it could be some 82k ohm resistor on the main powerboard that are broken? Does anyone have the knowledge to pin-point those on the pictures?

[tom66]

Re: Samsung LCD TV Black Screen (Weird!)

Perhaps it could be some 82k ohm resistor on the main powerboard that are broken? Does anyone have the knowledge to pin-point those on the pictures?

What makes you suspect that?

[HerculesDK]

Re: Samsung LCD TV Black Screen (Weird!)

What makes you suspect that?

I googled the problems and read that someone had similar problems, which were solved by fixing them. Do you know where or how to find these?

[selldoor]

Re: Samsung LCD TV Black Screen (Weird!)

Hi - 82k resistor is grey red orange and gold or silver bands


Can you post your pictures as requested in post 2 otherwise few people will look at them

[HerculesDK]

Re: Samsung LCD TV Black Screen (Weird!)

I've just spoken to a Samsung Tech and he said that it could be a eeprom error, which he has experienced on these models. Does anyone of you know where the eeprom chip is located and how do I reset it?

[HerculesDK]

Re: Samsung LCD TV Black Screen (Weird!)

Hi - 82k resistor is grey red orange and gold or silver bands


Can you post your pictures as requested in post 2 otherwise few people will look at them

I have added some of the pictures from the PDF file in the post below as you requested :-)

[HerculesDK]

Re: Samsung LCD TV Black Screen (Weird!)

I have marked an area in black in the back side of the mainboard. Is the chip located within the black circle the Eeprom chip? If so, should I solder pin 5-6 in order to reset it?

[HerculesDK]

Re: Samsung LCD TV Black Screen (Weird!)

Hi - 82k resistor is grey red orange and gold or silver bands


Can you post your pictures as requested in post 2 otherwise few people will look at them

I've uploaded some of the pictures from the PDF file in here now for those of you that do not want to download the PDF file.

[HerculesDK]

Re: Samsung LCD TV Black Screen (Weird!)

I've just spoken to a tv technician and he said that it might be the hdmi port (1) that have short circuited! This is very likely, but how do i test this? It is probably only the one that I used with the faulty hdmi cable.

[tom66]

Re: Samsung LCD TV Black Screen (Weird!)

What on earth is the HDMI stick? Sounds like a made up term to me.

N.B. The EEPROM issue only applies to older Samsung LExxRxx/Nxx/Mxx series (720p/1080p/1080p.) I don't think it applies to yours which is a later series 8 model.

[HerculesDK]

Re: Samsung LCD TV Black Screen (Weird!)

What on earth is the HDMI stick? Sounds like a made up term to me.

N.B. The EEPROM issue only applies to older Samsung LExxRxx/Nxx/Mxx series (720p/1080p/1080p.) I don't think it applies to yours which is a later series 8 model.

I think the technician that I spoke to today had a good point. He said that he had seen it before that a faulty HDMI cable caused a short circuit near the HDMI port, where it was used. And he said that if there are any components that are not functioning properly then the system is brought to a standstill. I also know which HDMI port he is speaking of, but how do I test it? And how do I disable it, so the rest of the system can proceed?

[HerculesDK]

Re: Samsung LCD TV Black Screen (Weird!)

I think perhaps that the problem lies here in the three HDMI ports IC units at the back. Is there anyway, where I can disable one of the port and make the system proceed? I was thinking about removing the chip and making a bridge connection where the chip was just to start up the TV? Or maybe transfer the chip to one of the others ports by bridging?

[tom66]

Re: Samsung LCD TV Black Screen (Weird!)

Those ICs are part of the EDID for the HDMI devices (one per port likely), containing the data about the display (manufacturer, model, maximum resolution, refresh rates etc.) In other words, they are read by the blu-ray player or other widget hooked up to your TV, not the TV itself.

I believe that HDMI is supposed to have a current limit on the small amount of power the TV can feed the devices (5V @ 55mA or so.) So, even if there was a short, I can't see it causing anything other than the port itself to die, not the whole TV.

[HerculesDK]

Re: Samsung LCD TV Black Screen (Weird!)

Those ICs are part of the EDID for the HDMI devices (one per port likely), containing the data about the display (manufacturer, model, maximum resolution, refresh rates etc.) In other words, they are read by the blu-ray player or other widget hooked up to your TV, not the TV itself.

I believe that HDMI is supposed to have a current limit on the small amount of power the TV can feed the devices (5V @ 55mA or so.) So, even if there was a short, I can't see it causing anything other than the port itself to die, not the whole TV.

So what do you suggest then? I really dont know that the problem is and what I can do to solve it?