Backlights but no picture - No 12v to Tcon board
Collapse
X
-
Comment
-
Re: Backlights but no picture - No 12v to Tcon board
Do you mean that the 0v reading on the base pin means that that component is faulty? Or that you think I measured the voltage incorrectly?Last edited by Stuckster; 10-24-2019, 04:59 PM.Comment
-
Never stop learning
Basic LCD TV and Monitor troubleshooting guides.
http://www.badcaps.net/forum/showthr...956#post305956
Voltage Regulator (LDO) testing:
http://www.badcaps.net/forum/showthr...999#post300999
Inverter testing using old CFL:
http://www.badcaps.net/forum/showthr...er+testing+cfl
Tear down pictures : Hit the ">" Show Albums and stories" on the left side
http://s807.photobucket.com/user/budm/library/
TV Factory reset codes listing:
http://www.badcaps.net/forum/showthread.php?t=24809Comment
-
Re: Backlights but no picture - No 12v to Tcon board
3.3K is not bad.
Right now you can try removing the LVDS cables from the main board first the try forcing on Q1 by connecting 100 Ohms resistor between GND and Gate pin and see if you will get 12VDC at Drain pin or not.
https://www.badcaps.net/forum/attach...2&d=1571874353Never stop learning
Basic LCD TV and Monitor troubleshooting guides.
http://www.badcaps.net/forum/showthr...956#post305956
Voltage Regulator (LDO) testing:
http://www.badcaps.net/forum/showthr...999#post300999
Inverter testing using old CFL:
http://www.badcaps.net/forum/showthr...er+testing+cfl
Tear down pictures : Hit the ">" Show Albums and stories" on the left side
http://s807.photobucket.com/user/budm/library/
TV Factory reset codes listing:
http://www.badcaps.net/forum/showthread.php?t=24809Comment
-
Re: Backlights but no picture - No 12v to Tcon board
3.3K is not bad.
Right now you can try removing the LVDS cables from the main board first the try forcing on Q1 by connecting 100 Ohms resistor between GND and Gate pin and see if you will get 12VDC at Drain pin or not.
https://www.badcaps.net/forum/attach...2&d=1571874353
Is there some other way to simulate 100 Ohms of resistance between GND and the Gate pin? Possibly using the meter?
Failing that, how certain are you at this stage that replacing the mainboard would essential fix the TV? And if I put a new mainboard in, from what we have already diagnosed, what is the chance that there could be something feeding back from the PSU or the Tcon and damaging Q1 on the mainboard? Or is that very unlikely?Comment
-
Re: Backlights but no picture - No 12v to Tcon board
Well, if you do not have the ability to solder the component on the main board then how are you going to fix the the board?
At this you know that the main board is not sending the 12V to run the T-CON, so there is nothing else you can do but replacing the main board with KNOWN WORKING BOARD.
You can take the board to the local repair shop and have them solder in the resistor for you.
Q1 is not being turned on by Q2 that is why we are trying to do force on with the resistor to provide the 12V to run the T-CON, if there is no problem with T-CON and other problems with the main board then all the functions of the TV should work, if not then you have more than just 12V to the T-CON board problem, so the only way to find out is to force on Q1 but since you do not know how to solder then it is moot point to do further troubleshooting the board. If force on gets the TV to function then we can use other signal to turn on Q1 instead but that will require board modification which you cannot do.Last edited by budm; 10-24-2019, 10:10 PM.Never stop learning
Basic LCD TV and Monitor troubleshooting guides.
http://www.badcaps.net/forum/showthr...956#post305956
Voltage Regulator (LDO) testing:
http://www.badcaps.net/forum/showthr...999#post300999
Inverter testing using old CFL:
http://www.badcaps.net/forum/showthr...er+testing+cfl
Tear down pictures : Hit the ">" Show Albums and stories" on the left side
http://s807.photobucket.com/user/budm/library/
TV Factory reset codes listing:
http://www.badcaps.net/forum/showthread.php?t=24809Comment
-
Re: Backlights but no picture - No 12v to Tcon board
Well, if you do not have the ability to solder the component on the main board then how are you going to fix the the board?
At this you know that the main board is not sending the 12V to run the T-CON, so there is nothing else you can do but replacing the main board with KNOWN WORKING BOARD.
You can take the board to the local repair shop and have them solder in the resistor for you.
Q1 is not being turned on by Q2 that is why we are trying to do force on with the resistor to provide the 12V to run the T-CON, if there is no problem with T-CON and other problems with the main board then all the functions of the TV should work, if not then you have more than just 12V to the T-CON board problem, so the only way to find out is to force on Q1 but since you do not know how to solder then it is moot point to do further troubleshooting the board. If force on gets the TV to function then we can use other signal to turn on Q1 instead but that will require board modification which you cannot do.
Is the fix you have suggested a temporary measure for further testing or will it actually fix the problem and if so if I'm able to get it repaired it is it ok to leave it like that permanently?Comment
-
Re: Backlights but no picture - No 12v to Tcon board
Maybe try there, they indicate that they have 1 mainboard, I don't know anything about them, might want to look their record up: http://a1tv.com.au/TCL.htmlComment
-
Re: Backlights but no picture - No 12v to Tcon board
Maybe try there, they indicate that they have 1 mainboard, I don't know anything about them, might want to look their record up: http://a1tv.com.au/TCL.html
I can get a new board off Ebay for around $270, which is still pricey. So I first need to arrange a refund on the faulty board to obtain the funds.
Might have to learn how to solder pcbs!Comment
-
Re: Backlights but no picture - No 12v to Tcon board
Ok, I guess they lied, in their ad it said, we are back in business, all parts are 120 dollars, there at the bottom: http://a1tv.com.au/index.htmlComment
-
Re: Backlights but no picture - No 12v to Tcon board
The board you are working on that's failing to power the Tcon was one you've just bought?
The one you've just looked at in post#51 is you feel, too expensive to buy for a 4 year old set?
Even though the Tcon is not being powered with the mainboard you already have, do you have sound, can you change channels etc to try and work out if the rest of the mainboard is functioning?
Is this your own TV or are you repairing it for someone else?Last edited by dick_barton; 10-25-2019, 11:24 AM.Willing to help but I'm no expert.Comment
-
Re: Backlights but no picture - No 12v to Tcon board
Post #1 I need to be 100% certain which board is faulty before I outlay money to replace it.
But it looks like he did outlay the money to get the replacement board to begin with, but I thought he did not want to spend big money on the board.
I have already determined:
- Tcon board not receiving any 12V.
- Mainboard only outputting 2.6v to audio/speakers
- Replacement PCB (no change)
- Replacement Tcon board (no change)
Bottom line, the replacement board we are troubleshooting is not sending the 12V either.Never stop learning
Basic LCD TV and Monitor troubleshooting guides.
http://www.badcaps.net/forum/showthr...956#post305956
Voltage Regulator (LDO) testing:
http://www.badcaps.net/forum/showthr...999#post300999
Inverter testing using old CFL:
http://www.badcaps.net/forum/showthr...er+testing+cfl
Tear down pictures : Hit the ">" Show Albums and stories" on the left side
http://s807.photobucket.com/user/budm/library/
TV Factory reset codes listing:
http://www.badcaps.net/forum/showthread.php?t=24809Comment
-
Re: Backlights but no picture - No 12v to Tcon board
Ok, I guess they lied, in their ad it said, we are back in business, all parts are 120 dollars, there at the bottom: http://a1tv.com.au/index.htmlComment
-
Re: Backlights but no picture - No 12v to Tcon board
My own TV.Comment
-
Re: Backlights but no picture - No 12v to Tcon board
Post #1 I need to be 100% certain which board is faulty before I outlay money to replace it.
But it looks like he did outlay the money to get the replacement board to begin with, but I thought he did not want to spend big money on the board.
I have already determined:
- Tcon board not receiving any 12V.
- Mainboard only outputting 2.6v to audio/speakers
- Replacement PCB (no change)
- Replacement Tcon board (no change)
Bottom line, the replacement board we are troubleshooting is not sending the 12V either.Comment
-
Re: Backlights but no picture - No 12v to Tcon board
Ended up returning the used board and received a refund through Paypal. Got the TV serviced and new mainboard installed. Repairs are warranted for 3 months. Thanks all for your help.
The moral of this story? Never buy used electronic components unless you can diagnose and repair them!Comment
-
Re: Backlights but no picture - No 12v to Tcon board
Thanks for the follow-up on the repair.Never stop learning
Basic LCD TV and Monitor troubleshooting guides.
http://www.badcaps.net/forum/showthr...956#post305956
Voltage Regulator (LDO) testing:
http://www.badcaps.net/forum/showthr...999#post300999
Inverter testing using old CFL:
http://www.badcaps.net/forum/showthr...er+testing+cfl
Tear down pictures : Hit the ">" Show Albums and stories" on the left side
http://s807.photobucket.com/user/budm/library/
TV Factory reset codes listing:
http://www.badcaps.net/forum/showthread.php?t=24809Comment
Related Topics
Collapse
-
Vizio e601i-A3 - Has Sound and Display, But No Backlight - Bad Power Supply Board or Bad LED Bulbs ?by Tynan DillI was given this TV from my great uncle. He said it just wouldn't turn on one day out of nowhere, replaced the TV, and gave it to me to possibly fix and use for myself.
Upon bringing it home and plugging it up, it showed a standby light.
I powered it on and without a flashlight, the display showed the "V" but the lighting is very dim, but visible.
The screen seems to blackout and stay black, but with a flashlight I can see the display.
With my Playstation 4 connected via HDMI, and running a game I can hear sound.
Assuming...7 Photos -
by m1ch43lzmHi, this is my personal laptop, which the original board (lets call it Board A) blew up PU8700 (TPS51486), making a hole on the board, i had left the laptop at my desk one day with the battery fully charged and didn't touch it for a week, but when i tried to turn it on it didn't
Thought the battery was dead, so i plugged in the charger then tried to power on, the power LED blinked once, charged LED still orange, unplugged the charger, plugged in again and I noticed the "magic smoke" smell, so i unplugged the charger, removed the back cover and saw the blown IC (the "magic... -
by AwsmessymailHello all,
I’ve tried to repair TVs in the past with some luck. Toms repair manuals got taken down and now thats a bit harder.
I picked this TV up hoping for a quick fix. When the TV would power on, only the backlights would come on. The owner told me they heard loud screeching before it shut off. This alone makes me want to think the main board has an issue.
As I researched, I found the TCON/driver boards were an issue on this unit. I went in troubleshooting the TCON but found good voltages on the TCON. I followed shop jimmys guide to test the transistors and they seem okay....5 Photos -
by maxim2511My Oled Tv is 55inch tv, 3 days ago I notice that middle of the screen is getting warmer and on picture I have ghosting, missing red color. Color red was still displaying, but it was not so strong as corners of the screen and watching some movies makes me angry.
Then I get an idea to take it apart and clean boards from dust.
In side of Tv was not so bad, I take compressed air in can, and gently blow up.
Also I was thinking to styrofoam sponge to isolate power board from screen that the middle of the screen will not worm so much. Because Led on screen when gets higher... -
Hi,
I have a VIZIO E70-E3.
Symptoms: Black screen, no picture, but LED backlights are working.
I probed the power board and voltages are as listed on the board.
Main board appears fine, too.
I believe the problem is either a bad T-CON board, or connection to LCD, or bad LCD.
There are two separate ribbon cables feeding the LCD.
If both are connected, the screen is black.
If only the ribbon cable that feeds the right side of the screen (when viewed from the front) is disconnected, the left side of the screen shows picture and... - Loading...
- No more items.
Comment