signal.quest
Senior Member
Last Activity: 12-06-2024, 11:33 PM
Joined: 10-03-2020
Location: Scranton, PA
-
I received the new TCON board and have installed it. I still don't see an image on the screen using the flashlight.... -
Thanks. What pins on the LVDS should I check? Do I check with respect to ground? I don't have a remote - can I power cycle or hit the buttons on the TV? I hope I don't need a new main board because they seem hard to find now. That might end this project.Leave a comment:
-
Thanks. Do you have any advice on the image flashlight issue besides replacing the TCON?Leave a comment:
-
I did measure on the lamp side, yes. Any idea what would cause them to not be within 2%? Can I fix this somehow? I would override the protection if it is easy to do, but I don't know how - do you?
I still am more concerned about being able to see the image on the screen with the flashlight. I have a TCON board on the way from aliexpress, but not due to arrive for 2 more weeks. I then would do an LED conversion and remove/bypass the CCFL components. Thanks.Leave a comment:
-
Here are the measurements on Ohms on the balance board from top of the TV to bottom of the TV:
T1: 152.3
T2: 152.9
T3: 154.4
T4: 152.1
T5: 152.7
T6: 150.9
T7: 151.0
T8: 152.5
T9: 154.0
T10: 153.4
T11: 153.5
T12: 155.3
HV Transformers:
T1: 12.6
T2: 12.9...Leave a comment:
-
The CCFL tester only lights the CFL or does not light if it is bad. I am a hobbyist and enjoy repairing/modifying thigs - I enjoy the torture of it. But only if I am successful in the end. Haha.Leave a comment:
-
I do have a backlight CCFL tester. All the bulbs light up dimly when I test them individually. I am not sure if this test rules out the bulbs completely. I think if the bulbs are starting to go bad they could pull too much current and cause the inverter circuit to shutdown in protection.Leave a comment:
-
Thank you, both for posting and trying to help me. I greatly appreciate it. 😀
All of the electrolytic caps pass testing with ESR meter. I also tested all small caps including SMD caps for shorts.
Is there a way to test the HV iverter transformers on the PSU? I don't have a ring tester. I don't see any visible damage or dry solder joints with a jewelers loop. I don't smell anything burnt.
I have tested each transformer output on the balance board with a multimeter and the resistance is basically identical on all. I also checked for damage and dry solder...Leave a comment:
-
Samsung LN40C630K1F LCD TV No Backlights and Flashlight Test Fail
Hi all,
I have been working on a Samsung LN40C630K1F LCD TV. On power up the backlights only briefly light up when first powered on then they go out (2 seconds to black). The flashlight test also fails. The sound works fine. Please see attached pics.
I have researched the forums a lot. I have watched the videos of trying to locate the bad CCFL or transformer and bypassing. I can't find any evidence of a bad transformer/CCFL. I verified I get 376V from the big caps to the fuse. I have used a small/cheap oscilloscope and it looks like the MOSFETs on the inverter... -
I tried another used main logic (A) board and got slightly better results. I could see some text. This makes me think all of the logic boards I am trying have different issues. Or could this mean the LCD panel or integrated TCON has failed? Please see the attached pictures and let me know your thoughts. I greatly appreciate your help.Leave a comment:
-
I tested the cable and it tested good. I then replaced the logic (A) board with the same model from ebay (it was used). The replacement board briefly powers on the backlight then goes into standby mode. I suspect the replacement board is bad. Maybe it has a power issue that is easily repairable? I check caps for shorts and did not find any. Do you have any advice on logic board troubleshooting/repair? Thanks.Leave a comment:
-
I masked the last 3 pins as in your diagram with red box. However, the display is still black.
Is it possible that the main board is working for audio and HDMI identification by laptop (Panasonic) but the video output is failed? Perhaps the video processor is bad or something similar? Thanks....Leave a comment:
-
I did try to clean all connections on the ribbon cable and board receptacles. This did not make a difference. Next, I will attempt to mask the pins you suggested. Thanks again.Leave a comment:
-
Yes, I have 12V after removing everything. Can you please tell me what other test points on the panel I need to check for specific voltages? Is there a way I can test for shorted lines on the panel? Thank you.Leave a comment:
-
EazyBone, thanks for advice. I will try to do that soon. I reseated the yellow connection cables and now the faint clicking sound on the main board has gone away. But still black screen on display.Leave a comment:
-
I just connected laptop to HDMI and randomly pressed the side buttons until I heard audio coming from the laptop. Sadly, still nothing but black screen on LCD panel. I tried again to tap the connector on both board with no success.Leave a comment:
-
I tried cleaning and reseating the LVDS cable on both mainboard and panel sides. I also tried applying pressure to the cable connector. But there is still black screen. I noticed this time the mainboard makes a faint (hard to hear) ticking sound when the power is initially connected. This sound repeats each time I disconnect and reconnect the power. I also have never heard audio coming from the mainboard when I had laptop connected to the HDMI to play video file....Leave a comment:
-
My sincere apologies. I have now disconnected the LVDS cable and jumpered the 12V connection points that you suggested. The results are now a complete black screen when both yellow connection cables are connected. When the cables are disconnected the screen is white where the cables are disconnected and black on the opposite side. You are correct that there are no colored lines down the center now. Please tell what is next to test. Thank you very much.Leave a comment:
-
Since, I blocked all pins using tape but the 12V source on the LVDS cable on the panel side of the connection isn't that the same as jumpering trom the points you mentioned? If not, what am I not understanding about this?
Before disassembling the TV I did not test using a flashlight (torch) to see an LCD image. I was not aware of that method until after I had already taken it apart.
I have watched youtube videos and I am concerned about the panel side tabs or a shorted line. I fear that I was not aware enough when reassembling the panel and might have accidentally...Leave a comment:
-
I did the following tests:
1. I disconnected both yellow highlighted connections in the picture you sent. This created a white screen on the disconnected side and colored lines in the center. Please see picture.
2. I tried to disconnect just 1 of the yellow connection cables. This made a black screen on both sides, but the colored lines in the center.
3. I checked the panel circuit for shorts on the capacitors but did not find any.
4. I checked the panel board and found 12V, 3.3V, and 24V at different sections. I did not check all possible points. Please let me...Leave a comment:
No activity results to display
Leave a comment: