Badcaps.net Forum
Go Back   Badcaps Forums > Electronics Theory and Troubleshooting > Troubleshooting TVs and Video Sources
Register FAQ Members List Social Groups Calendar Search Today's Posts Mark Forums Read

 
Thread Tools Display Modes
Old 06-09-2012, 05:23 PM   #101
Jahson
Badcaps Veteran
 
Join Date: May 2012
City & State: London
My Country: UK
Line Voltage: 230Vac 50hz
I'm a: Knowledge Seeker
Posts: 214
Default Re: 42lg3000-za No Picture but got sound

Cheers Budm yea i have come across a similar repair kit. Im not at the set, will be there on monday. I cant remember if i did check those 3 points.
Jahson is offline   Reply With Quote
Old 06-12-2012, 01:01 PM   #102
Jahson
Badcaps Veteran
 
Join Date: May 2012
City & State: London
My Country: UK
Line Voltage: 230Vac 50hz
I'm a: Knowledge Seeker
Posts: 214
Default Re: 42lg3000-za No Picture but got sound

yesday i was doing some probing on the mainboard, & i came across a zener diode that was reading .000, i double check.

ZD503 is the one giving me this reading ive circled it in blue.

The zener diode was still on the board when i took the reading.
Jahson is offline   Reply With Quote
Old 06-12-2012, 01:04 PM   #103
Jahson
Badcaps Veteran
 
Join Date: May 2012
City & State: London
My Country: UK
Line Voltage: 230Vac 50hz
I'm a: Knowledge Seeker
Posts: 214
Default Re: 42lg3000-za No Picture but got sound

Yesday i was doing some probing on the mainboard, & i came across a zener diode that was reading .000, i double check.

ZD503 is the one giving me this reading ive circled it in blue.

The zener diode was still on the board when i took the reading.
Attached Images
File Type: jpg ZD503.jpg (374.8 KB, 48 views)
Jahson is offline   Reply With Quote
Old 06-12-2012, 01:06 PM   #104
tom66
Badcaps Veteran
 
Join Date: Apr 2011
City & State: Leeds (University)
My Country: UK
Line Voltage: 230Vac 50Hz
I'm a: Student Tech
Posts: 26,697
Default Re: 42lg3000-za No Picture but got sound

Check on ohms too. Do you have a picture of the underside of the board where the diode came from?
__________________
Please do not PM me for help and support. Questions belong on the public forum.

68 LED/LCD TVs, 5 monitors, 26 plasma TVs, and 2 AVR 6.1 amplifiers saved from the dump!
Totally free service manuals database: http://www.toms-service-manuals.com/ (Contact me for requests or contributions.)

I have successfully fixed (from best --> worst build quality):
1 Pioneer KURO 9G, 10 Panasonic LCD/Plasma, 1 Sony LCD, 1 NEC Plasma, 2 Yamaha HTS, 4 Sharp LCDs, 5 Toshiba LCDs, 7 Philips Plasma/LCD, 1 Hitachi Plasma, 10 LG LCD/Plasma, 15 Samsung LED/LCD/Plasma, 1 Thomson Plasma, 1 Atec LCD, 1 Hanspree LCD, 1 Xerox LCD, 1 Harwa LCD, 2 Proview LCD, 2 Hyundai LCD, 1 "Onn" LCD, 1 Grundig LCD, 1 Dell LCD, 1 iiyama LCD, 1 Acer LED, 1 Logik LCD, 1 Baird (China) LCD, 6 Bush LCDs, 19 Vestel LCDs
tom66 is offline   Reply With Quote
Old 06-12-2012, 01:28 PM   #105
Jahson
Badcaps Veteran
 
Join Date: May 2012
City & State: London
My Country: UK
Line Voltage: 230Vac 50hz
I'm a: Knowledge Seeker
Posts: 214
Default Re: 42lg3000-za No Picture but got sound

Okay just check it on 200ohms it reads 01.0 in both directions.
Attached Images
File Type: jpg SAM_0013.jpg (396.5 KB, 28 views)
File Type: jpg SAM_0014.jpg (350.5 KB, 31 views)
Jahson is offline   Reply With Quote
Old 06-14-2012, 04:13 PM   #106
Jahson
Badcaps Veteran
 
Join Date: May 2012
City & State: London
My Country: UK
Line Voltage: 230Vac 50hz
I'm a: Knowledge Seeker
Posts: 214
Default Re: 42lg3000-za No Picture but got sound

Got hold of a next 42LG3000-ZA tried the inverter boards, no joy also tried the AV board no joy, changed the mainboard no joy?

The T-Con was different so could not change it.

Whots the chances its the T-con the problem?
Jahson is offline   Reply With Quote
Old 06-14-2012, 04:59 PM   #107
selldoor
Slow Learner
 
Join Date: Dec 2010
City & State: Lancashire UK
Posts: 7,193
Default Re: 42lg3000-za No Picture but got sound

Hi - is this another non-working set?
By the way I have been looking back and still cannot see that we sorted out testing the
inverter transformers. Perhaps you can do comparison tests with the second lot.
Try and do all the pins - like 1 to 1 1to2..........1 to12 then 2 to3 ......2 to12 and so on.
Just record those in the 300 -2000 range. Tomorrow if I remember I will try and hunt down those transformers -
selldoor is offline   Reply With Quote
Old 06-14-2012, 05:21 PM   #108
tom66
Badcaps Veteran
 
Join Date: Apr 2011
City & State: Leeds (University)
My Country: UK
Line Voltage: 230Vac 50Hz
I'm a: Student Tech
Posts: 26,697
Default Re: 42lg3000-za No Picture but got sound

What was the panel in the other TV? The problem could still be in the main board, because the other main board may be configured for the wrong panel, causing no display.
tom66 is offline   Reply With Quote
Old 06-16-2012, 06:21 AM   #109
Jahson
Badcaps Veteran
 
Join Date: May 2012
City & State: London
My Country: UK
Line Voltage: 230Vac 50hz
I'm a: Knowledge Seeker
Posts: 214
Default Re: 42lg3000-za No Picture but got sound

The other set had a broken screen, tell the truth i was in a hurry an changed the inverters, av board, mainboard. This was like 12am

The mainboard and av board part numbers are the same.

The inverters had a different model number ended .50 (not at set cant remember full details) mines ended 54 & 55.

So i was going try test again but with my old inverters back in set.


I thought it be a good idea to buy the smashed set, so i could test an see if things are the same.

I try get the T-Con part numbers later when my friend gets back, The T-con from the smash set was twiced the size of my original T-con.
Jahson is offline   Reply With Quote
Old 06-18-2012, 11:54 AM   #110
Jahson
Badcaps Veteran
 
Join Date: May 2012
City & State: London
My Country: UK
Line Voltage: 230Vac 50hz
I'm a: Knowledge Seeker
Posts: 214
Default Re: 42lg3000-za No Picture but got sound

I put back the original inverters still no joy, with the replacement mainboard.

I notice iT gives 3 red pulsing flashes before it switches to the blue colour to say its on? if thats any help.

original inverters master = vit71053.54 logah rev:0
original slave = vit71053.55 logah rev:0

Replacement master = vit71053.50 logah rev:3
Replacement slave = vit71053.51 logah rev:3

Original T-con p/n - T370XW02 VC CTRL BD
Replacement T-con p/n - T420XW01 CTRL BD
Jahson is offline   Reply With Quote
Old 06-18-2012, 02:03 PM   #111
Jahson
Badcaps Veteran
 
Join Date: May 2012
City & State: London
My Country: UK
Line Voltage: 230Vac 50hz
I'm a: Knowledge Seeker
Posts: 214
Default Re: 42lg3000-za No Picture but got sound

Quote:
Originally Posted by selldoor View Post

Try and do all the pins - like 1 to 1 1to2..........1 to12 then 2 to3 ......2 to12 and so on.
Just record those in the 300 -2000 range. Tomorrow if I remember I will try and hunt down those transformers -
It seems confusing in preview mode? didnt write it like that. Everything to the far right is T2.

Also stated when (meter set to 2k)

Meter set to 200 ohms

Master Inverter Test
Transformer T1 Transformer T2

1-2 = 00.6 same
1-3 = 00.6 same
1-4 = 00.6 same
1-5 = 00.6 same
1-6 = 00.6 same
1-7 = .519 (meter set 2k) .521
1-8 = .519 (meter set 2k) .521
1-9 = .536 (meter set 2k) 1 left side all settings
1-10= .536 (meter set 2k) 1 left side all settings
1-11= .536 (meter set 2k) .539
1-12= .519 (meter set 2k) .539

2-3 = 00.6 same
2-4 = 00.6 same
2-5 = 00.6 same
2-6 = 00.6 same
2-7 = .518 (meter set 2k) .522
2-8 = .518 (meter set 2k) .522
2-9 = .536 (meter set 2k) 1 left side all settings
2-10=.536 (meter set 2k) 1 left side all settings
2-11=.536 (meter set 2k) .540
2-12=.536 (meter set 2k) .540

3-4= 00.6 same
3-5= 00.6 same
3-6= 00.6 same
3-7= .519 (meter set 2k) .522
3-8= .519 (meter set 2k) .522
3-9= .537 (meter set 2k) 1 left side all settings
3-10=.537 (meter set 2k) 1 left side all settings
3-11=.537 (meter set 2k) .540
3-12=.537 (meter set 2k) .540

4-5= 00.7 same
4-6= 00.7 same
4-7=.519 (meter set 2k) .523
4-8=.519 (meter set 2k) .523
4-9=.537 (meter set 2k) 1 on left side all settings
4-10=.537 (meter set 2k) 1 on left side all settings
4-11=.537 (meter set 2k) .539
4-12=.537 (meter set 2k) .539

5-6= 00.7 same
5-7=.520 (meter set 2k) .522
5-8=.520 (meter set 2k) .522
5-9=.538 (meter set 2k) 1 on left side all settings
5-10=.538 (meter set 2k) 1 on left side all settings
5-11=.538 (meter set 2k) .540
5-12=.538 (meter set 2k) .540

6-7=.520 (meter set 2k) .522
6-8=.520 (meter set 2k) .522
6-9=.538 (meter set 2k) 1 on left side all settings
6-10=.538 (meter set 2k) 1 on left side all settings
6-11=.538 (meter set 2k) .540
6-12=.538 (meter set 2k) .540

7-8=00.7 same
7-9=15.4 1 on left side all settings
7-10=15.4 1 on left side all settings
7-11=15.4 15.2
7-12=15.4 15.2

8-9=15.4 1 on left side all settings
8-10=15.4 1 on left side all settings
8-11=15.4 15.2
8-12=15.4 15.2

9-10=00.6 same
9-11=00.6 1 on left side all settings
9-12=00.6 1 on left side all settings

10-11=00.6 1 on left side all settings
10-12=00.6 1 on left side all settings

11-12=00.6 same


Same=T2 same as T1, also i did try separate the readings,
Now i go do the slave transformer.
Jahson is offline   Reply With Quote
Old 09-16-2012, 12:00 PM   #112
Jahson
Badcaps Veteran
 
Join Date: May 2012
City & State: London
My Country: UK
Line Voltage: 230Vac 50hz
I'm a: Knowledge Seeker
Posts: 214
Default Re: 42lg3000-za No Picture but got sound

Did someone find the fix, how do i test the ccfl's
Jahson is offline   Reply With Quote
Old 09-16-2012, 03:39 PM   #113
cadiman
Badcaps Veteran
 
Join Date: Mar 2010
City & State: chesterland Ohio
Posts: 398
Default Re: 42lg3000-za No Picture but got sound

I was able to tell just by looking at them. You will see burn marks on the inside.

There are a few types pending panel maker. The ones you have should clip in. I prefer soldered myself. Thats what I do when replacing them.

I always have panels around so I just use what I have from other 42" panels.

The main issue with different models is the lcd panel including the t-con needs to stay with that mainboard. The backlight may be similar and the power supply will normally be the same with these since all inverters run on 24v and use the same control system for the most part. You just need to remember the lcd display, t-con and mainboard must stay together as far as L/G 42lg20.30.50 You can swap the mainboards only within the model families like all 26,32,37,42,lg 30-ua models can use the same mainboard The 26 will need a modified plug (it is missing from the larger models) but the board pinout is still there.
cadiman is offline   Reply With Quote
Old 01-04-2013, 03:33 PM   #114
fantoma
New Member
 
Join Date: Aug 2012
City & State: 8700
My Country: romania
I'm a: Knowledge Seeker
Posts: 2
Default Re: 42lg3000-za No Picture but got sound

Did you repair that lcd?
Maibe i can help you.
i just fix a master inverte board for 42lg3000 lcd.
fantoma is offline   Reply With Quote
Old 01-04-2013, 04:02 PM   #115
fantoma
New Member
 
Join Date: Aug 2012
City & State: 8700
My Country: romania
I'm a: Knowledge Seeker
Posts: 2
Default Re: 42lg3000-za No Picture but got sound

Assemble all parts together.
Plug in all connectors.
Power on the lcd. Whith your multimeter set on DC , check between pins 1,2,3,4 or 5, and 6,7,8,9 or 10 ,on master inverter power plug CN1, if there is 24Vdc, if so, check between pins 6,7,8,9 or 10 and pin 12, if there apear 5Vdc on pin 12 when you power up your lcd, and dissapears when you power down yor lcd from remote control. If all are ok, there is an defective master inverter board.
Now, on the master inverter board find U1, located betwen connectors CN1 and CN2, this in an 5Vdc regulator (78M05), on pin 1 you must find 24Vdc , on pin 3 5Vdc, pin 2 is chassis and is grounded.
If you don't have 24Vdc on pin 1, check fuse. The fuse is F1, located near pin 1 of CN1 power connector, is black an marked 2.0 . Unplug LCD from mains, replace fuse F1 (short it just for test), and you got a fully working LCD.
Please post here your results to see if this helped you.
Best regards...
fantoma is offline   Reply With Quote
Old 03-09-2013, 09:40 AM   #116
Alessio
New Member
 
Join Date: Mar 2013
City & State: Pescara
My Country: iTALIA
I'm a: Knowledge Seeker
Posts: 4
Default Re: 42lg3000-za No Picture but got sound

Quote:
Originally Posted by fantoma View Post
Assemble all parts together.
Plug in all connectors.
Power on the lcd. Whith your multimeter set on DC , check between pins 1,2,3,4 or 5, and 6,7,8,9 or 10 ,on master inverter power plug CN1, if there is 24Vdc, if so, check between pins 6,7,8,9 or 10 and pin 12, if there apear 5Vdc on pin 12 when you power up your lcd, and dissapears when you power down yor lcd from remote control. If all are ok, there is an defective master inverter board.
Now, on the master inverter board find U1, located betwen connectors CN1 and CN2, this in an 5Vdc regulator (78M05), on pin 1 you must find 24Vdc , on pin 3 5Vdc, pin 2 is chassis and is grounded.
If you don't have 24Vdc on pin 1, check fuse. The fuse is F1, located near pin 1 of CN1 power connector, is black an marked 2.0 . Unplug LCD from mains, replace fuse F1 (short it just for test), and you got a fully working LCD.
Please post here your results to see if this helped you.
Best regards...

Hello
I have 7vdc on Pin 3
22,5Vdc on Pin 1

Help?
Alessio is offline   Reply With Quote
Old 03-10-2013, 12:13 PM   #117
Alessio
New Member
 
Join Date: Mar 2013
City & State: Pescara
My Country: iTALIA
I'm a: Knowledge Seeker
Posts: 4
Default Re: 42lg3000-za No Picture but got sound

Hello,
F1 > 24v
F2 > 0v




How to replace F2?

KOAC 8A FUSE
Alessio 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


All times are GMT -6. The time now is 09:48 AM.


Badcaps.net Technical Forums 2003 - 2014
Powered by vBulletin ®
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.

Did you find this forum helpful?