Panasonic 48" LED TV, backlight on but no picture

safesurfer65 · 12-01-2015, 03:16 AM

Hello all

Have a Panasonic 48" LED TV model no. TX-48AS640B. Just over 1 year old. When switched on the backlight comes on but no picture is displayed. Can hear the menu being navigated. Suspecting main board, any ideas ? Hope someone can help.

thanks

Mal

**truep** · 12-01-2015, 10:47 AM

Check for voltage on both sides of the TCON fuse. It should be near one of the connectors
going to the main board. If you send a clear picture of the TCON board we should be able to point it out. (it's the one at the bottom of your picture) There should be 12V or 5V on both sides of the fuse. Some nay not have a fuse though.

safesurfer65 · 12-01-2015, 11:14 AM

Hi

Thanks for that. Think I identified the fuse (circled). 12v both sides !

**budm** · 12-01-2015, 11:36 AM

Try having one ribbon cable between the T-CON and the LCD panel connected one at a time to see what you get on the screen.

safesurfer65 · 12-01-2015, 11:56 AM

Hi

Tried disconnecting individual and both cables from the T-con to the screen. Made no difference.

thx

**wreksta** · 02-04-2017, 11:27 AM

Hi all been a while I too am facing this blank screen issue on same tv any info and tcon fuse tests fine

**Davi.p** · 02-04-2017, 02:56 PM

You have lost too the warranty proof?? :-)
The defect seem sto stay on tcon, can someone pubblish a shopjimmy picture of that board? i can't connect to it.

**sordids999** · 02-04-2017, 04:17 PM

recently done a 40 inch panasonic with bad LEDS

just a thought though

**ReeceyBurger123** · 02-04-2017, 05:11 PM

Quote:

Originally Posted by sordids999

recently done a 40 inch panasonic with bad LEDS

just a thought though

Backlight on no picture......

**sordids999** · 02-05-2017, 04:36 AM

Quote:

Originally Posted by ReeceyBurger123

Backlight on no picture......

opps i must read more before posting

**ReeceyBurger123** · 02-05-2017, 04:45 AM

Quote:

Originally Posted by sordids999

opps i must read more before posting

Lolol

**Davi.p** · 02-05-2017, 07:17 AM

Jesus Christ that smokes? That changes capacitors?

Also Jesus Christ chooses... PANASONIC...

**wreksta** · 02-21-2017, 05:59 AM

Hi has anyone resolved this issue I've tried tcon and to no Avail have the new main board so will post back when fitted

**ReeceyBurger123** · 02-21-2017, 06:27 AM

Keep us updated

**wreksta** · 02-21-2017, 10:28 AM

well thats the main board and tcon replaced for good working ones and still nothing but a blank screen

also checked out all screen tabs etc no damage faults etc
im starting to think its the psu but nothing visual or blown

does any have a service manual or know the voltage the power board gives to main

**freakaftr8** · 02-21-2017, 10:34 AM

Fuse on panel FRP boards?

**wreksta** · 02-21-2017, 10:50 AM

fuse on frp where is this fuse like mate

**freakaftr8** · 02-21-2017, 11:10 AM

Located in the long boards that are attached to the panel itself. They are concealed within the frame.

Of course this is just a hunch. I have seen panels that have fuses built on to these boards as a precautionary secondary step incase t-con fails

**Davi.p** · 02-21-2017, 09:35 PM

Are you sure the backlight is present like OP?

sintv · 02-22-2017, 03:01 PM

I recently had Vestel type 48" Toshiba with backlights ok but no video. Turned out to be the PSU though I didnt get to component level

12-01-2015, 10:47 AM	#2
truep Badcaps Veteran Join Date: Aug 2010 City & State: Flower mound, TX My Country: USA Line Voltage: 120VAC 60 HZ I'm a: Knowledge Seeker Posts: 362	Re: Panasonic 48" LED TV, backlight on but no picture Check for voltage on both sides of the TCON fuse. It should be near one of the connectors going to the main board. If you send a clear picture of the TCON board we should be able to point it out. (it's the one at the bottom of your picture) There should be 12V or 5V on both sides of the fuse. Some nay not have a fuse though.

12-01-2015, 11:36 AM	#4
budm Badcaps Veteran Join Date: Feb 2010 City & State: S.F. Bay area My Country: USA Line Voltage: 120V 60Hz I'm a: Knowledge Seeker Posts: 38,511	Re: Panasonic 48" LED TV, backlight on but no picture Try having one ribbon cable between the T-CON and the LCD panel connected one at a time to see what you get on the screen. __________________ 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=24809

12-01-2015, 11:56 AM	#5
safesurfer65 Member Join Date: Feb 2014 City & State: Aberdeen My Country: Scotland I'm a: Knowledge Seeker Posts: 74	Re: Panasonic 48" LED TV, backlight on but no picture Hi Tried disconnecting individual and both cables from the T-con to the screen. Made no difference. thx

02-04-2017, 11:27 AM	#6
wreksta Badcaps Veteran Join Date: Aug 2013 City & State: tyne and wear My Country: england I'm a: Knowledge Seeker Posts: 505	Re: Panasonic 48" LED TV, backlight on but no picture Hi all been a while I too am facing this blank screen issue on same tv any info and tcon fuse tests fine

02-04-2017, 02:56 PM	#7
Davi.p Badcaps Veteran Join Date: Sep 2009 City & State: Milan My Country: Italy I'm a: Hobbyist Tech Posts: 1,692	Re: Panasonic 48" LED TV, backlight on but no picture You have lost too the warranty proof?? :-) The defect seem sto stay on tcon, can someone pubblish a shopjimmy picture of that board? i can't connect to it.

02-04-2017, 04:17 PM	#8
sordids999 Badcaps Veteran Join Date: May 2013 City & State: United Kingdom My Country: uk Line Voltage: 240v I'm a: Hobbyist Tech Posts: 1,844	Re: Panasonic 48" LED TV, backlight on but no picture recently done a 40 inch panasonic with bad LEDS just a thought though

02-05-2017, 07:17 AM	#12
Davi.p Badcaps Veteran Join Date: Sep 2009 City & State: Milan My Country: Italy I'm a: Hobbyist Tech Posts: 1,692	Re: Panasonic 48" LED TV, backlight on but no picture Jesus Christ that smokes? That changes capacitors? Also Jesus Christ chooses... PANASONIC... Last edited by Davi.p; 02-05-2017 at 07:18 AM..

02-21-2017, 05:59 AM	#13
wreksta Badcaps Veteran Join Date: Aug 2013 City & State: tyne and wear My Country: england I'm a: Knowledge Seeker Posts: 505	Re: Panasonic 48" LED TV, backlight on but no picture Hi has anyone resolved this issue I've tried tcon and to no Avail have the new main board so will post back when fitted

02-21-2017, 06:27 AM	#14
ReeceyBurger123 Never Give Up ! Join Date: May 2014 City & State: Telford My Country: Britain Line Voltage: 240 VAC 50Hz I'm a: Student Tech Posts: 7,124	Re: Panasonic 48" LED TV, backlight on but no picture Keep us updated

02-21-2017, 10:28 AM	#15
wreksta Badcaps Veteran Join Date: Aug 2013 City & State: tyne and wear My Country: england I'm a: Knowledge Seeker Posts: 505	Re: Panasonic 48" LED TV, backlight on but no picture well thats the main board and tcon replaced for good working ones and still nothing but a blank screen also checked out all screen tabs etc no damage faults etc im starting to think its the psu but nothing visual or blown does any have a service manual or know the voltage the power board gives to main

02-21-2017, 10:34 AM	#16
freakaftr8 Badcaps Veteran Join Date: Oct 2012 City & State: Folsom, CA My Country: USA Line Voltage: 120vac 60hz I'm a: Hobbyist Tech Posts: 3,720	Re: Panasonic 48" LED TV, backlight on but no picture Fuse on panel FRP boards? __________________ Did I leave the soldering iron on?

02-21-2017, 10:50 AM	#17
wreksta Badcaps Veteran Join Date: Aug 2013 City & State: tyne and wear My Country: england I'm a: Knowledge Seeker Posts: 505	Re: Panasonic 48" LED TV, backlight on but no picture fuse on frp where is this fuse like mate

02-21-2017, 11:10 AM	#18
freakaftr8 Badcaps Veteran Join Date: Oct 2012 City & State: Folsom, CA My Country: USA Line Voltage: 120vac 60hz I'm a: Hobbyist Tech Posts: 3,720	Re: Panasonic 48" LED TV, backlight on but no picture Located in the long boards that are attached to the panel itself. They are concealed within the frame. Of course this is just a hunch. I have seen panels that have fuses built on to these boards as a precautionary secondary step incase t-con fails Last edited by freakaftr8; 02-21-2017 at 11:13 AM..

02-21-2017, 09:35 PM	#19
Davi.p Badcaps Veteran Join Date: Sep 2009 City & State: Milan My Country: Italy I'm a: Hobbyist Tech Posts: 1,692	Re: Panasonic 48" LED TV, backlight on but no picture Are you sure the backlight is present like OP?

02-22-2017, 03:01 PM	#20
sintv Member Join Date: Feb 2015 City & State: cowdenbeath My Country: scotland I'm a: Knowledge Seeker Posts: 24	Re: Panasonic 48" LED TV, backlight on but no picture I recently had Vestel type 48" Toshiba with backlights ok but no video. Turned out to be the PSU though I didnt get to component level

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