Badcaps.net Forum
Go Back   Badcaps Forums > Troubleshooting Hardware & Devices and Electronics Theory > Troubleshooting TVs and Video Sources
Register FAQ Calendar Search Today's Posts Mark Forums Read

 
Thread Tools Display Modes
Old 05-22-2022, 12:45 PM   #1
Xristakis795
Senior Member
 
Join Date: Mar 2021
City & State: Athens
My Country: Greece
I'm a: Knowledge Seeker
Posts: 114
Default lg 42lc55 7 times blinking and after goes out

hi to all
i have the above model lcd tv
the problem is like the title blinking the green led 7 times after is steady green for 30 seconds i can see picture without backlight used a lens and after i hear something like sound from the speaker i think and the green led goes out with the image of course
thanks in advance
Xristakis795 is offline   Reply With Quote
Old 05-22-2022, 01:29 PM   #2
nomoresonys
Badcaps Veteran
 
Join Date: Jan 2013
City & State: midwest
My Country: U.S.
I'm a: Knowledge Seeker
Posts: 8,196
Default Re: lg 42lc55 7 times blinking and after goes out

need good straight on pictures of every board and one of the whole back as to see how everything is connected and a clear closeup of the map/legend of the powerboard.
nomoresonys is offline   Reply With Quote
Old 05-22-2022, 02:16 PM   #3
Xristakis795
Senior Member
 
Join Date: Mar 2021
City & State: Athens
My Country: Greece
I'm a: Knowledge Seeker
Posts: 114
Default Re: lg 42lc55 7 times blinking and after goes out

ok sir
i have take some pictures
Attached Images
File Type: jpg IMG_20220522_121342_011.jpg (682.2 KB, 26 views)
File Type: jpg IMG_20220522_121358_408.jpg (669.9 KB, 22 views)
File Type: jpg IMG_20220522_121429_211.jpg (652.9 KB, 18 views)
Xristakis795 is offline   Reply With Quote
Old 05-22-2022, 03:05 PM   #4
dskall
Badcaps Veteran
 
dskall's Avatar
 
Join Date: Oct 2016
City & State: Bakersfield ca.
My Country: usa
Line Voltage: 120VAC 60Hz
I'm a: Knowledge Seeker
Posts: 2,817
Default Re: lg 42lc55 7 times blinking and after goes out

Need to test backlights.
https://www.badcaps.net/forum/showth...er+testing+cfl
__________________
I assume no responsibility for any stupid suggestions I might post.
dskall is offline   Reply With Quote
Old 05-23-2022, 01:00 AM   #5
Xristakis795
Senior Member
 
Join Date: Mar 2021
City & State: Athens
My Country: Greece
I'm a: Knowledge Seeker
Posts: 114
Default Re: lg 42lc55 7 times blinking and after goes out

thanks for the answer sir
and i believe maby its backlight problem
in my case if you notice from the foto i have two plugs go to the ccfl lights
, but each plug has one wire
how can i connect external a ccfl light for testing the inverter ?
one or two lamp must i connect ?
Xristakis795 is offline   Reply With Quote
Old 05-23-2022, 02:44 PM   #6
Xristakis795
Senior Member
 
Join Date: Mar 2021
City & State: Athens
My Country: Greece
I'm a: Knowledge Seeker
Posts: 114
Default Re: lg 42lc55 7 times blinking and after goes out

sir
just to be sure
i can test it with one lamp ccfl right ?
Xristakis795 is offline   Reply With Quote
Old 05-23-2022, 03:10 PM   #7
dskall
Badcaps Veteran
 
dskall's Avatar
 
Join Date: Oct 2016
City & State: Bakersfield ca.
My Country: usa
Line Voltage: 120VAC 60Hz
I'm a: Knowledge Seeker
Posts: 2,817
Default Re: lg 42lc55 7 times blinking and after goes out

Looks like 2 circuits. Test one at a time. Appears ground is chassis. Also high voltage.
dskall is offline   Reply With Quote
Old 05-24-2022, 02:25 AM   #8
Xristakis795
Senior Member
 
Join Date: Mar 2021
City & State: Athens
My Country: Greece
I'm a: Knowledge Seeker
Posts: 114
Default Re: lg 42lc55 7 times blinking and after goes out

i understood
close circuit with ground of chassis
so you tell me to test only one ccfl with one edge to the plug and the other to chassis of tv
or can i use two ccfl with common edge the chassis ?
Xristakis795 is offline   Reply With Quote
Old 05-26-2022, 02:54 PM   #9
Xristakis795
Senior Member
 
Join Date: Mar 2021
City & State: Athens
My Country: Greece
I'm a: Knowledge Seeker
Posts: 114
Default Re: lg 42lc55 7 times blinking and after goes out

can i do bypass on the ic backlight so to pass the fault with backlight so i can convert it to led ?
Xristakis795 is offline   Reply With Quote
Old 05-26-2022, 05:58 PM   #10
dskall
Badcaps Veteran
 
dskall's Avatar
 
Join Date: Oct 2016
City & State: Bakersfield ca.
My Country: usa
Line Voltage: 120VAC 60Hz
I'm a: Knowledge Seeker
Posts: 2,817
Default Re: lg 42lc55 7 times blinking and after goes out

https://www.youtube.com/watch?v=q4C_...l=MackoyTechPh
dskall is offline   Reply With Quote
Old 05-27-2022, 03:23 AM   #11
Xristakis795
Senior Member
 
Join Date: Mar 2021
City & State: Athens
My Country: Greece
I'm a: Knowledge Seeker
Posts: 114
Default Re: lg 42lc55 7 times blinking and after goes out

thanks one more time for your quick answer
in my case the problem is green led blinking 7 times stabilizing for 10 seconds
almost in this duration i can see picture without backlight with the help of a lens
and after the led goes out and the picture tv goes to protect mode
my question is how can avoid this problem and tv doesnt go to protect mode
if i fix this i can convert it to led i have done again in other tv
is there someone ic responsible for the backlight and to do it bypass ?
i have done in a philips tv lcd and work in lg tv is possible in my case ?
Xristakis795 is offline   Reply With Quote
Old 05-29-2022, 01:33 PM   #12
Xristakis795
Senior Member
 
Join Date: Mar 2021
City & State: Athens
My Country: Greece
I'm a: Knowledge Seeker
Posts: 114
Default Re: lg 42lc55 7 times blinking and after goes out

hi again in my case the responsible inverter ic is oz9965gn
i read ho can i do bypass but i cant understand because there isn t schematic

(OZ9925GN Protection Remove

We solder the LED on the 13th leg. Protection is disabled. The first element with 13 legs is a capacitor. Here we solder it in parallel.)

can anybody with more experience to help me ?
Xristakis795 is offline   Reply With Quote
Old 05-29-2022, 01:45 PM   #13
lotas
Badcaps Veteran
 
Join Date: Jan 2016
City & State: Sochi
My Country: russia
I'm a: Knowledge Seeker
Posts: 876
Default Re: lg 42lc55 7 times blinking and after goes out

parallel capacitor.
Attached Images
File Type: png parallel capacitor.PNG (19.2 KB, 8 views)
lotas is offline   Reply With Quote
Old 05-29-2022, 01:50 PM   #14
Xristakis795
Senior Member
 
Join Date: Mar 2021
City & State: Athens
My Country: Greece
I'm a: Knowledge Seeker
Posts: 114
Default Re: lg 42lc55 7 times blinking and after goes out

and what type led must i use ? i mean characterestic volts ?
the tv isn led is lcd with ccfl lamps
Xristakis795 is offline   Reply With Quote
Old 05-29-2022, 02:05 PM   #15
lotas
Badcaps Veteran
 
Join Date: Jan 2016
City & State: Sochi
My Country: russia
I'm a: Knowledge Seeker
Posts: 876
Default Re: lg 42lc55 7 times blinking and after goes out

Regular red LED
Attached Images
File Type: jpg red.jpg (4.2 KB, 4 views)
lotas is offline   Reply With Quote
Old 05-30-2022, 10:01 AM   #16
Xristakis795
Senior Member
 
Join Date: Mar 2021
City & State: Athens
My Country: Greece
I'm a: Knowledge Seeker
Posts: 114
Default Re: lg 42lc55 7 times blinking and after goes out

do you know voltage ?
Xristakis795 is offline   Reply With Quote
Old 06-05-2022, 12:40 PM   #17
Xristakis795
Senior Member
 
Join Date: Mar 2021
City & State: Athens
My Country: Greece
I'm a: Knowledge Seeker
Posts: 114
Default Re: lg 42lc55 7 times blinking and after goes out

sir dskall
i found the the schematic of power supply in electrotanya and i have confuse and i wanted from your experience little more help
i thinking to use 2 lamps ccfl T5 for the simulation in the same time and no one each time
my problem is from the plan where i connect the connectors of the lamps
the first lamp the one connector on the plug p401 and the other connector on the capacitor c404 wich connected on the ground with the symbol P or on the trimmer v302 wich connected with the ground
similar the second lamp must i connected between the plug p402 and capacitor c409 or trimmer v302 ?
thanks in advance
Attached Files
File Type: pdf lg_lp42slpv2ev3_eay38640201_eay39702801_psu_sch.pdf (1.44 MB, 3 views)
Xristakis795 is offline   Reply With Quote
Old 06-18-2022, 02:41 PM   #18
Xristakis795
Senior Member
 
Join Date: Mar 2021
City & State: Athens
My Country: Greece
I'm a: Knowledge Seeker
Posts: 114
Default Re: lg 42lc55 7 times blinking and after goes out

sorry i want to correct something
the problem finally is the tv at the start is standby
when press the power on blinking the green led 7 times after is steady the green led for 10 seconds approximately
you can see with the help of lens display without backlight and after the tv goes in stand by again
it doesnt goes out as i had tell at the start
does anybody of you similar experience ??
Xristakis795 is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump



Badcaps.net Technical Forums 2003 - 2022
Powered by vBulletin ®
Copyright ©2000 - 2022, Jelsoft Enterprises Ltd.
All times are GMT -6. The time now is 05:55 AM.
Did you find this forum helpful?