LCD Panel Garbled, unless I loosen the plug.

[RaddyKewl]

Hello,

I purchased this LCD panel and driver board on eBay for use in my iMac G3 mod. I just tried hooking them up, and my video is garbled. If I pull the video cable out slightly on one edge, the image corrects itself. Does anyone have any idea of what could be causing this, and how to fix it? I'm almost tempted to cut a wire on the edge of the plug that I've pulled out, but I want to see if anyone else has any better suggestions first.

 

Brand: AUO
Model: G150XTN03.0

 

Technical details: http://www.panelook.com/G150XTN03.0_AUO_15_LCM_overview_15340.html

 

LCD Panel Listing: https://www.ebay.com/itm/G150XTN03-0-LCD-Screen-Display-Panel-15-1024-768-Resolution/233329762897

 

Driver Board Listing: https://www.ebay.com/itm/HDMI-VGA-DVI-LCD-Control-panel-For-G150XTN01-0-G150XTN03-0-1024x768-LCD-Screen/372761821568

 

My pics: https://imgur.com/gallery/rS95L98

 

Thank You,
-Cali

[Bombastinator]

“Cut a wire on the edge of a plug I’ve pulled out”

 

yeaaahh... there may be more to this one than is being mentioned

[RaddyKewl]

So with the edge that is loosened, in theory, that pin isn't connected when I get a clear image, so if I cut that wire, I'd get a clear image. But with my limited experience in electronics, that doesn't seem like a good idea... that's why I'm asking for a second opinion.

[Bombastinator]

3 minutes ago, RaddyKewl said:

So with the edge that is loosened, in theory, that pin isn't connected when I get a clear image, so if I cut that wire, I'd get a clear image. But with my limited experience in electronics, that doesn't seem like a good idea... that's why I'm asking for a second opinion.

It’s a lot more likely that there’s something wrong with the pin or the pin connector.  Randomly cutting stuff sounds like a very bad idea to me personally. Pulled out wire sounded a lot more like pulled out wire than a plug loosened on one edge.  It’s real possible that when you loosen the plug you’re causing those wires to make contact rather than breaking contact.

[RandleMcmurphy]

35 minutes ago, RaddyKewl said:

So with the edge that is loosened, in theory, that pin isn't connected when I get a clear image, so if I cut that wire, I'd get a clear image. But with my limited experience in electronics, that doesn't seem like a good idea... that's why I'm asking for a second opinion.

Hi, I haunt the forum, your not nuts btw. Here's what I have dug up.

panel pinout

driver pinout

props for providing lots of info in your post.

 

Theory A: Your wiring harness is configured wrong. It looks like your floating the data select pin when you jimmy the connector. So instead of 8 bit mode the display panel operates in 6 bit mode. (see panel pinout pdf, page 16).

 

Theory B: Your wiring harness has some even/odd channels swapped (see driver pinout, page 6, section CN25).

 

As far as a solution? idk, I would really just have to look at everything, see what goes where. Perhaps someone else with more in depth knowledge could shed some light on things.

 

My initial impression is your display is fine, and your driver is fine. Unless you cooked the driver chip, socks on carpet, that's a no no.

 

Best of luck.

[RandleMcmurphy]

1 hour ago, RaddyKewl said:

So with the edge that is loosened, in theory, that pin isn't connected when I get a clear image, so if I cut that wire, I'd get a clear image. But with my limited experience in electronics, that doesn't seem like a good idea... that's why I'm asking for a second opinion.

So this is fun, it looks like there's conflicting information (page 4 of pdf 'panel pinout').

[RaddyKewl]

Thank you for the reply and the schematics.

 

Looking at the video harness, there doesn't appear to be any wires to pins 19 and 20.

 

On the attached image, I've X'd the pins without wires.

[RaddyKewl]

It looks like the pinout in both sets of schematics match each other.

[RandleMcmurphy]

12 minutes ago, RaddyKewl said:

Thank you for the reply and the schematics.

 

Looking at the video harness, there doesn't appear to be any wires to pins 19 and 20.

 

On the attached image, I've X'd the pins without wires.

Based on the data sheet, I think if you ran a wire from pin 20 to ground, it should fix your problem.

 

The 'old version' states, if pin 20 is a NC, you should be in 6bit mode, where as the new version states if pin 20 is a NC, your in 8 bit mode.

 

The driver board is 8bit only (unless I missed something). By 'Jerry plugging' your connector, I think you NULL-ed the last 2 bits, implying your board thinks its in 6 bit mode? so by forcing pin 20 to ground, you would force the board into 8 bit mode?

 

I'm not 100% sure, I don't mess around with display panels that much, but it would be a good place to start. Grounding pin 20 should be perfectly safe.

[RaddyKewl]

5 minutes ago, RandleMcmurphy said:

Based on the data sheet, I think if you ran a wire from pin 20 to ground, it should fix your problem.

 

The 'old version' states, if pin 20 is a NC, you should be in 6bit mode, where as the new version states if pin 20 is a NC, your in 8 bit mode.

 

The driver board is 8bit only (unless I missed something). By 'Jerry plugging' your connector, I think you NULL-ed the last 2 bits, implying your board thinks its in 6 bit mode? so by forcing pin 20 to ground, you would force the board into 8 bit mode?

 

I'm not 100% sure, I don't mess around with display panels that much, but it would be a good place to start. Grounding pin 20 should be perfectly safe.

So if I got a jumper (like from an old hard drive) and jump pin 20 to 19... that would ground it?

[RaddyKewl]

I see the flaw... that won't work because the connector wouldn't fit.

[RandleMcmurphy]

5 minutes ago, RaddyKewl said:

So if I got a jumper (like from an old hard drive) and jump pin 20 to 19... that would ground it?

Umm, In the most scientific way possible, I would cram a wire in the vacant spot of the connector where pin 20 is, then connect the other end of that wire to another ground. Strictly for testing.

Spoiler

 

[RaddyKewl]

I'll have to dig around and find some wire... Maybe an old IDE cable or a phone wire. It'll probably be tomorrow before I can continue working on it.

[RaddyKewl]

Thank you for your help.

[RandleMcmurphy]

1 minute ago, RaddyKewl said:

Thank you for your help.

your welcome, in a pinch a bread tie works. Grounding pin 20 should immediately fix your panel, if that was in fact the problem.

 

Best of luck, let me know how things turn out.

[RaddyKewl]

It doesn't seem to be working. I tried using a bread tie to bridge pin 20 to 13. I tried it on the driver board and on the LCD. Perhaps I'm not getting the wire in well enough to make a good connection.

[RandleMcmurphy]

12 hours ago, RaddyKewl said:

It doesn't seem to be working. I tried using a bread tie to bridge pin 20 to 13. I tried it on the driver board and on the LCD. Perhaps I'm not getting the wire in well enough to make a good connection.

Did you remove the 'insulation' from the bread tie? Once everything is bridged, try cycling power, the mode select might be part of the display panels boot sequence. If that doesn't work, assume the panel is in 8 bit mode, which could means there is something messed up with something else, probably Rin4 +-.

 

That's really all the advice I have, as a last resort, you could always snip the wires connected to pins 17 & 18. See if that 'fixes' it. Depending on the mode, you might be truncating the display color bits if you remove 17 & 18.

[RandleMcmurphy]

This also might help. User_s_guide_of_M.NT68676.2A_controller_board_V1.1.pdf

 

I guess there's an auto mode?

[RaddyKewl]

Yes, I stripped the insulation. I bridged it without power then turned it on... just in case I was to short something else out.

 

I'll attempt the Auto Mode, but even the driver board menus come up distorted even with no source.

[RaddyKewl]

On 1/25/2020 at 11:27 AM, RandleMcmurphy said:

This also might help. User_s_guide_of_M.NT68676.2A_controller_board_V1.1.pdf

 

I guess there's an auto mode?

So I followed the directions in that user guide. It didn't work exactly as the directions stated, but I was able to get into factory mode, and changed the LVDS value from 1 to 0, and that fixed the screen, and removed the garbled mess. Thank you very much.