Re: Samsung UE55H7080 black screen (sound is working)
The last weeks I was really terribly busy. I had no time to check more on the T-CON board, hence, I decided to buy a new one (or let's better say a working one from another TV from ebay). The TV works again!!!
Steradiant
Member
Last Activity: 07-15-2019, 01:03 AM
Joined: 05-11-2019
Location: Vienna
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Re: Samsung UE55H7080 black screen (sound is working)
Thanks, it was absolutely understandable and I thought of this but honestly, I don't see where this should get me. I can follow a trace but don't know what the trace is all about or what voltage I should have there. For me only measurement points are meaningful, where I have at least a hint if they should be 0 or not.
I also opened the bottom now (pic attached) but again no meaningful labels for me. On the other hand, like already stated above, we think it shouldn't be a problem of the panel or...Leave a comment:
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Re: Samsung UE55H7080 black screen (sound is working)
Of course not, would be nice though if they'd tell you "hey, this voltage needs to be xxx"
Also a no here, I am afraid that this is mounted on an IC with a heat-conductive paste and I don't have one at home at the moment.
Here pops again the question up how I can follow them. Without a circuit plan this is nearly impossible without removing the tcon board from the tv.
For the labeling of the connections from the tcon to the...Leave a comment:
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Re: Samsung UE55H7080 black screen (sound is working)
Yes, I'm doing more test than stated because I thought it could be helpful (and if not, at least it shouldn't be a harm).
I brought the new cases up because of this request:
And sound is working for all test cases I've tried yet.
Yes, which I already tried to note twice. And I've tried to state it more clear in the table attached above. And yes, the behavior of the backlight correlates with the P_DIM voltages. If they are 0V it is turned off, if they are around...Last edited by Steradiant; 05-13-2019, 08:09 AM.Leave a comment:
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Re: Samsung UE55H7080 black screen (sound is working)
The sound and backlight rows belong to the experiments in the same column respectively. As I noted, for these tests I always disconnected one cable at a time. Hence, I got the backlight on steadily by either removing cable Ex1 or Ex2.
In a later text, I've also tried to disconnect two cables at a time, namely:
Ex1 and Ex2 unplugged; Ex3 and Ex4 plugged: Backlight goes on steadily, sound working
Ex1 and Ex2 plugged; Ex3 and Ex4 unplugged: Backlight stays off, sound workingLeave a comment:
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Re: Samsung UE55H7080 black screen (sound is working)
I'm sorry if it was unclear but that the backlight is working at all came up during the tests recommended here. I didn't know that when I was starting the thread.
I repeated the experiments and made a table of the results (see attachments). I always disconnected one cable at a time, so 3 were plugged, 1 was unplugged for this tests.
In a particular area of the tcon board? There are a lot of capacitors on there.
When disconnecting both...Leave a comment:
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Re: Samsung UE55H7080 black screen (sound is working)
I see what you mean. After the post from budwich #17 I anyway tried disconnecting also the bottom connectors to the panel (which I also tried to tell in my post). Sorry for the confusion.
I disconnected always one at a time from the bottom two connectors and neither with the right cable connected, nor with the left one connected I can see something on the screen. It stays black....Leave a comment:
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Re: Samsung UE55H7080 black screen (sound is working)
Man, I wrote the following:
"When I disconnect one of the top cables (see red areas in attachment) of the tcon board, the backlight turns on as I switch on the TV. The backlight also turns on if both cables are disconnected. By disconnecting the bottom cables, nothing (obvious) changes." in Post #18. There I only referred to the attachment when I was talking about the two cables on the TOP. I've also disconnected the two ribbon cables at the bottom and like explained twice now, everything...Last edited by Steradiant; 05-12-2019, 10:16 AM.Leave a comment:
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Re: Samsung UE55H7080 black screen (sound is working)
Like explained above, I did this (at least for the tcon board). Nothing changes when I disconnect one of the bottom two ribbon cables. When I disconnect either the top ribbon cable or the other cable with 6 connections, the backlight turns on.
I've spotted a 3rd LED (LED2) on the tcon board which stays off all the time. Don't know if this helps....Last edited by Steradiant; 05-12-2019, 09:04 AM.Leave a comment:
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Re: Samsung UE55H7080 black screen (sound is working)
How can you conclude that now? Shouldn't a panel failure be better visible on the screen?Leave a comment:
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Re: Samsung UE55H7080 black screen (sound is working)
When I disconnect one of the top cables (see red areas in attachment) of the tcon board, the backlight turns on as I switch on the TV. The backlight also turns on if both cables are disconnected. By disconnecting the bottom cables, nothing (obvious) changes.
If you need any information about voltage levels, just let me know in which ones you're interested in....Last edited by Steradiant; 05-12-2019, 08:41 AM.Leave a comment:
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Re: Samsung UE55H7080 black screen (sound is working)
I've checked the voltages on the CNM803 now after switching on the TV
N.C. 0V
P_DIM4 0V
P_DIM3 0V
P_DIM2 0V
GND 0V
P_DIM1 0V
A13V 12.6V
OD_ON/OFF 3.2V
A13V 12.6V
OD_LEVEL 0V
A13V 12.6V
BLU_ON/OFF 4.8V
A13V 12.6V
PS_ON 3.2V
A13V 12.6V
GND 0V
GND 0V
GNV 0V
Vamp 12.6V
Vamp 12.6V
Vamp 12.6V
GND 0V
I have to note that I don't have an oscilloscope at home right now,...Leave a comment:
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Re: Samsung UE55H7080 black screen (sound is working)
Sadly I also don't have a service manual. Is there any way to get one?
What makes me suspicious is, that the BLU_ON bin shows 3.2V when the connector is disconnected (hence, the LEDs are on; as explained above) and the 4.6V when the plug is connected and the TV is switched on.
Should the integrated driver be a IC on the power supply board?
So to follow the path I would have to remove the power supply board from the TV and follow the paths on the bottom. Or have you thought of any...Leave a comment:
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Re: Samsung UE55H7080 black screen (sound is working)
You write "if". I honestly can't tell if this is the pin I'm looking for.
Furthermore, you wrote that the voltage should go from high (approx 3V) to low (0V) when switching on the TV. This pin shows the opposite behavior though....Leave a comment:
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Re: Samsung UE55H7080 black screen (sound is working)
Like I said, I don't have any connection to satellite or similar on my measurement place. BLU_ON raises from 0V when the TV is off to 4.6V when I switch the TV on.Leave a comment:
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Re: Samsung UE55H7080 black screen (sound is working)
Sorry for asking so much but where is the bl_on located? I only find BLU_ON on the power supply board (on the right hand side).
The voltage at the wire which is labeled with STB and ON changes from 0 to 12.63V when I switch the TV on.
I have to note, that every external connection to my TV is disconnected, only the power is available at the station where I measure stuff....Last edited by Steradiant; 05-11-2019, 08:37 AM.Leave a comment:
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Re: Samsung UE55H7080 black screen (sound is working)
Thanks for the explanation. Yes, the backlight turned on after unplugging this connector. What does this tell us?...Leave a comment:
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Re: Samsung UE55H7080 black screen (sound is working)
Thanks for the advice but could you please tell me which board you mean with "motherboard". The one at the bottom I suppose?...Leave a comment:
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Samsung UE55H7080 black screen (sound is working)
Hello,
some days ago my Samsung UE55H7080 broke. When I switched on the TV, the screen stayed black (2 hours ago I was still watching TV). The sound is still working, I can hear how I can switch channels, go into the menu and so on. I've already tried to plug the TV off for the whole night and plug it back on the next day and it didn't help.
I decided to open the TV because I thought it might be a problem with the power supply for the backlight. Attached you can find some pictures of the inside of the TV.
What I've already checked:
- The fuse... -
Re: New Members - please post your introductions here
Hello all!
I'm glad that I found this forum. The main reason was, because my TV stopped working some days ago and I want to fix it or let's better say to figure out what the problem is would be already sufficient for me.
I have some knowledge about electronics and stuff so it would be a great thing for me do improve also in the practical part and I'm looking forward to firstly receive good ideas and later on also to contribute myself.
CheersLeave a comment:
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