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AnalogRocks Forum Moderator
Joined: 08 Mar 2006 Posts: 26690 Location: Toronto, Ontario, Canada
TV/Projector: Sony 1252Q, AMPRO 4000G
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Link Posted: Thu Apr 23, 2015 5:42 pm Post subject: LG M4715CG / M4715CCBA back lite but no picture |
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Hello all. Found one of these LCD industrial monitors. Ran the PC into it, PC sent 1080p, screen backlight is on just the ocasional flickering across the top of the screen then the middle of the screen.
I have it open,
Any common areas to look at?
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AnalogRocks Forum Moderator
Joined: 08 Mar 2006 Posts: 26690 Location: Toronto, Ontario, Canada
TV/Projector: Sony 1252Q, AMPRO 4000G
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Link Posted: Sat Apr 25, 2015 7:16 pm Post subject: |
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Anyone?
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AnalogRocks Forum Moderator
Joined: 08 Mar 2006 Posts: 26690 Location: Toronto, Ontario, Canada
TV/Projector: Sony 1252Q, AMPRO 4000G
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Link Posted: Sat Apr 25, 2015 7:54 pm Post subject: |
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Got a picture via S-video. Full screen sttic but that's more then what VGA gave me.
It actually went clear for a second too!
There's a 6" wide bright bar on the right side of the screen about 10" out too. Video is displayed but it's a brighter band. Stationary, not rolling like hum bars, and vertical not horizontal.
Just noticed the picture within the band is color inverted (negative) and shifted down by 1/4 inch
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AnalogRocks Forum Moderator
Joined: 08 Mar 2006 Posts: 26690 Location: Toronto, Ontario, Canada
TV/Projector: Sony 1252Q, AMPRO 4000G
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Link Posted: Sat Apr 25, 2015 8:46 pm Post subject: |
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And now the right half of the screen is blank...
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winny
Joined: 09 Oct 2013 Posts: 403 Location: Sweden
TV/Projector: BD808s, BG1209/2
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Link Posted: Sun Apr 26, 2015 7:12 pm Post subject: |
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Store it until you can find another one identical, swap the hopefully working video boards/LCD-drivers from it and have one working? Service manual? Toss it?
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Curt Palme CRT Tech
Joined: 08 Mar 2006 Posts: 24303 Location: Langley, BC
TV/Projector: All of them!
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Link Posted: Mon Apr 27, 2015 2:25 pm Post subject: |
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Bad T con board or bad system board would be my guess.
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winny
Joined: 09 Oct 2013 Posts: 403 Location: Sweden
TV/Projector: BD808s, BG1209/2
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AnalogRocks Forum Moderator
Joined: 08 Mar 2006 Posts: 26690 Location: Toronto, Ontario, Canada
TV/Projector: Sony 1252Q, AMPRO 4000G
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Link Posted: Mon Apr 27, 2015 5:02 pm Post subject: |
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Interesting! Tha sure saves time soldering!
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AnalogRocks Forum Moderator
Joined: 08 Mar 2006 Posts: 26690 Location: Toronto, Ontario, Canada
TV/Projector: Sony 1252Q, AMPRO 4000G
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Link Posted: Mon Apr 27, 2015 5:03 pm Post subject: |
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Curt Palme wrote: | Bad T con board or bad system board would be my guess. |
Any way to test, or do I just start replacing boards?
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AnalogRocks Forum Moderator
Joined: 08 Mar 2006 Posts: 26690 Location: Toronto, Ontario, Canada
TV/Projector: Sony 1252Q, AMPRO 4000G
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Curt Palme CRT Tech
Joined: 08 Mar 2006 Posts: 24303 Location: Langley, BC
TV/Projector: All of them!
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Link Posted: Wed Apr 29, 2015 9:26 pm Post subject: |
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It's possible, but it's common for production runs to change, so all you can do is try it. Did you check the 2 amp SMT fuse on the orignal board? Those can blow open for no reason, giving the exact symptom you describe.
<edit> never mind on the fuse, you did get a pix with Svideo. Not the fuse.
If the small print part numbers match up, you're OK. if not, they won't work.
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AnalogRocks Forum Moderator
Joined: 08 Mar 2006 Posts: 26690 Location: Toronto, Ontario, Canada
TV/Projector: Sony 1252Q, AMPRO 4000G
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Link Posted: Wed Apr 29, 2015 9:42 pm Post subject: |
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Here they are. Slightly different numbers. The eBay part is newer:
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Curt Palme CRT Tech
Joined: 08 Mar 2006 Posts: 24303 Location: Langley, BC
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Link Posted: Wed Apr 29, 2015 10:02 pm Post subject: |
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I'll bet they won't work. Made that mistake a few times. You'll probably get a pix, but it may have lines, be pixellated, etc.
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AnalogRocks Forum Moderator
Joined: 08 Mar 2006 Posts: 26690 Location: Toronto, Ontario, Canada
TV/Projector: Sony 1252Q, AMPRO 4000G
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Link Posted: Thu Apr 30, 2015 4:34 pm Post subject: |
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Another one just showed up with the right part number for $16.50 and free shipping. Time to roll the bones...
http://www.ebay.com/itm/121520703977
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AnalogRocks Forum Moderator
Joined: 08 Mar 2006 Posts: 26690 Location: Toronto, Ontario, Canada
TV/Projector: Sony 1252Q, AMPRO 4000G
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Link Posted: Sat May 30, 2015 7:35 pm Post subject: |
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Tried this but no go. Still have the screen band and the right half of the screen is blank. Maybe one of the LCD driver boards or input board?
I can't even get a picture with s-video now.
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AnalogRocks Forum Moderator
Joined: 08 Mar 2006 Posts: 26690 Location: Toronto, Ontario, Canada
TV/Projector: Sony 1252Q, AMPRO 4000G
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Link Posted: Fri Jun 12, 2015 2:48 am Post subject: |
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AnalogRocks wrote: | Tried this but no go. Still have the screen band and the right half of the screen is blank. Maybe one of the LCD driver boards or input board?
I can't even get a picture with s-video now. |
On these LCD's are there separate boards for the left and right sides of the screen?
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AnalogRocks Forum Moderator
Joined: 08 Mar 2006 Posts: 26690 Location: Toronto, Ontario, Canada
TV/Projector: Sony 1252Q, AMPRO 4000G
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Link Posted: Wed Jul 22, 2015 8:00 pm Post subject: |
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Which Caigs Deoxit version should I order to clean this TV? It has an intermittent connection and was left out in the rain making for some dirty connections.
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AnalogRocks Forum Moderator
Joined: 08 Mar 2006 Posts: 26690 Location: Toronto, Ontario, Canada
TV/Projector: Sony 1252Q, AMPRO 4000G
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Link Posted: Sun Aug 30, 2015 6:29 pm Post subject: |
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Tried the new T-con board, got no picture. I have it open and I'll be cleaning things with Caig's. I may just swap back to the other board to see if I can get it to go.
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Jeremy112
Joined: 28 Sep 2006 Posts: 2645 Location: Fond du Lac, WI
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Link Posted: Sun Aug 30, 2015 9:36 pm Post subject: |
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You have to remember with LCD displays that the possibility exists that the LCD panel itself is toast. The only boards directly on the LCD panel are likely a couple PCBs that the T-CON board connects to, those could very likely have failed.
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AnalogRocks Forum Moderator
Joined: 08 Mar 2006 Posts: 26690 Location: Toronto, Ontario, Canada
TV/Projector: Sony 1252Q, AMPRO 4000G
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Link Posted: Tue Sep 01, 2015 6:33 am Post subject: |
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I had a picture with this one via S-video. I think the input board may be fugged.
I cleaned all the contacts with Caigs. The power and back light will stay on now. So one step closer
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