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VGA Problem Revisited

by CemAygun / December 7, 2008 7:49 AM PST

Well, I bougth a LA32A550 Samsung LCD TV, and like many people I cannot use it with any of my notebooks through the VGA. I have 2 different notebooks, (AMD and Intel) with two different graphics chipsets. None of them can be detected as an input through VGA with any of the cables I tried, although both of them detects the tv.

I know there is an output because I can see it perfectly on a regular monitor, with all the cables. I tried all the tutorials (switching tv off etc.) but they don't work for me. PC input is always grayed out...

Searching around on the net for days, I came to conclusion that you need some sort of special cable. I don't think it is possible to find where I live, but I can build it. So any suggestions, or even better the specs of the cable I need so that I can use the TV as I intended to?

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Update the BIOS?
by Samsung_HD_Tech Samsung staff / December 7, 2008 8:45 AM PST
In reply to: VGA Problem Revisited

Have you updated the BIOS?

It sounds completely unrelated - but it makes a difference.

Keep me posted.


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Which BIOS? :)
by CemAygun / December 7, 2008 12:23 PM PST
In reply to: Update the BIOS?

Well if we are talking about notebook bioses, both are up to date. But if it is the TV bios, the LA series don't have that option, I don't know why. Their LN versions has a different menu with the SW update option.

I still suspect the cable. The problem is its impossible to find a full set cable here. They all have the basic pins (RGBHV) It's even hard to find a cable with full set of wires in it Sad If I knew which pins are needed by the TV, I can modify my cable and get it out of the equation.

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by Samsung_HD_Tech Samsung staff / December 7, 2008 1:58 PM PST
In reply to: Which BIOS? :)

I was referring to the computer BIOS. Heh.. I should have specificed that. Wink

You checked the website for both of them and they have the newest release? I hate to sound redundant, but I just wanted to verify.


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Definetely sure :)
by CemAygun / December 7, 2008 2:25 PM PST
In reply to: Computer

Yep. I am also an active member for one of them's forum (MSI Wind)So everything is as up to date as it can be. I am still suspecting the cable. Only if I could find which pins the TV needs, then I would be able to fix the cable. I cut open one of the cables to make sure. As I thought it uses 5 pins only (plus ground on the casing)In some of the forums people suggested that the TV needs one / or some of the other pins to be detect the connection. I need to find out which because its almost impossible to find a 15 wire cable and connect them all...

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by Samsung_HD_Tech Samsung staff / December 7, 2008 2:50 PM PST
In reply to: Definetely sure :)

Okay, the next issue would be the cable.

If you hook the cable up, turn on the television first and then boot the computer. If you right click > Properties > Settings, are you able to detect the panel as a secondary monitor?

Also, does the screen flash when you do a VGA out Control+f* key on your laptop?

It may be the cable, but that would definitely be a consideration if you suspect that might be the cause.


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Yep it is detected :)
by CemAygun / December 7, 2008 5:45 PM PST
In reply to: Excellent...

Yes XP detects the tv and enables the option to extend the desktop onto it. It does detect it as generic monitor though, it cannot detect the brand, model etc. It even detects the removal or reconnection of the cable from tv; xp successfully gives the device plugged/unplugged sound every time...

The refresh rate is set to 60Hz, and I know it is enabling the VGA out properly because if I take out the cable from tv and put it to a samsung lcd (pc monitor) I get the picture perfectly...

Actually the problem I have, like many others seems to be the automatic signal detection routine on the tv. Some people reported having the vga working even though it is not detected. Older models have the option to turn on PC connection, whether there is a signal or not. These people can use the connection. But with this batch, it does not let you turn the connection on if it cannot detect a signal. Some people also put on a device that can be detected, enable the PC connection, then remove the cable and plug in the device they really want to use...

I also met a few posts claiming that putting the VGA cable other way around solved their problem. This is strange because the cable is supposed to be directionless. The connections are the same on both ends, no cross connections etc...

As a result, I am really having a hard time justifying what is happening here. In the end, this is a very very old technology which Samsung already has(and no funny comments about the "new 1080p HD technology" please, it has been around and available for almost 20 years, just search for Silicon Graphics Indigo). All their PC monitors run without a single problem on common computers with common cables. And if they believe they need a cable with uncommon specs/connections etc, they should just supply it. It does not have to be free, but it should be available.

Anyway thanks a lot for all your efforts. If someone points out which pins are actually required, maybe we can solve the mystery Happy

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by CemAygun / December 11, 2008 6:36 AM PST
In reply to: Yep it is detected :)

Well, in the end one of the cables I bought worked! Strangely enough, it is one of the cheaper ones. I will have a detailed check on pins to "pin out" the extra connections Happy The cable does not look much thicker so I believe it only has 1 or 2 more wires connected which makes the difference. I'll post the pins as soon as I test so that people will have the information Samsung inexplicably withholds, and they will be able to check a cable before buying to make sure that it will work...

By the way, the way windows detects the monitor (the tv) also changed. It detects it as a plug&play monitor now (instead of a generic monitor) and only shows the supported modes. So I suspect pins 11 and 12, the monitor id pins make the difference. But I will be able to tell for sure after testing.

As a first impression, I was delighted by the sharpness and clarity of the picture (especially the text) but devastated as much by the lack of color and contrast on default settings. Especially the black looks really "grey", washed out...I will try to fix this by fine tuning but it seems that it might not be fruitful, as most of the picture tuning options that are present for HDMI are not present on pc input. Another strange thing I noticed is the lack of "just scan" option which is especially intended for pc usage (1 to 1 pixel mapping) but it is understandable if that only works through digital inputs (HDMI)

Anyway, I'll keep posted for anyone interested...

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Same problem
by bugracan.balcik / December 11, 2008 6:38 AM PST
In reply to: Yep it is detected :)

I'm having the totally same problem on LE46A956.

I recently updated the Firmware of the Television and I tried it with three Notebooks.

When I connect these three Notebooks with same cable to Samsung 2232BW 22" or LG 37LP1R-ZE 37" it works fine.

If you will find any solution, I will appreciate if you will keep me updated.

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Will test ASAP
by CemAygun / December 14, 2008 8:05 AM PST
In reply to: Same problem

Well, my multimeter went dead on me, and I could not check the cable yet because I am waiting for the new meter to arrive. But I am almost sure that it is just an extra wire, and not the cable quality etc. I can only prove it when I am able to check the working cable though.

All the nonworking cables had the same 5 pin only connection, as this is enough for a regular PC LCD to work. And they did not work with the tv.

My other findings are that almost all image processing options are disabled through VGA. This is why the image is dull and pale. This is somewhat understandable as VGA input was intended to turn TV into a PC monitor and it is more accurate when working with photos etc. But lack of just scan mode is crazy, as I can have it at the same resolution (1080p) via component connection from my Xbox360. 1:1 pixel mapping is the exact thing you need when you connect to a pc...The overscan was not so bad thogh and I could use my PC almost perfectly, with little loss on the top (the start menu, taskbar was visible)Maybe even that can be fine tuned.

As far as I can see, Samsung does not want to bother with analogue connections any more, and pushes the consumers to digital inputs (HDMI). Because to use the features that they advertise, you definitely need the digital connection...

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samsung monitors/TVs and vga cable
by budwich / December 18, 2008 8:25 AM PST
In reply to: Will test ASAP

I have a similar problem connecting to a samsung hd tv. I found that the none working cable doesn't have any ground pins connected in the cable (pins 6,7,8,10,11) while a working cable has all of those. With the "bad cable" just connected to the TV (no PC connected to the other end), the "PC source" is grey out. With a "good vga cable" connected to the TV (no PC connected to the other end), the "PC source" is "brighten" and can be selected. Upon selection, the TV responses with "no signal detected"... as expected because there is no PC connected at that time... connecting one ultimately shows everything OK... great. But for the other cable (bad one), if you try to select the "greyed out" PC source, the TV response still with "no cable connected" with or without a PC on the other end. It would appear that the samsung "stuff" is a little "particular" to types of cable... having said that, I would expect cables to have some ground pin continuity in them from end to end.

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samsung and vga cables
by budwich / December 18, 2008 8:38 AM PST

Based on a "hint" from a few posts back, I just went back and checked the "non-working" vga cable and sure enough, it only has continuity (for grounds I guess) on the metal casing of the connector ends... and no other "ground pins connections" are provided. So it appears that samsung's implementation (at least on some) wants / needs some other source of ground returns in the cabling.

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Yes, exactly
by CemAygun / December 18, 2008 5:31 PM PST
In reply to: samsung and vga cables

Well, all the non working cables I checked were 6 wire only. They all have the ground on the outer casing and they have the regular Red, Green, Blue, Horizontal and Vertical Sync pins. There are multiple ground pins on the standard VGA connector. On non working cables non of them are connected...

The working cable seems to have connection on ALL pins, plus the casing. So unfortunately I was not able to pinpoint a "magic" pin. I was counting on the monitor ID pin(s) as only with the working cable the TV is recognized and windows automatically detects the supported modes.

I also found out something strange. I noticed that the cable used on the "good cable" was not much thicker than the one used in non-working ones. So I thought there is no chance that this cable can hold 15(+1) wires. Considering that cable cost me only 5$ (so there should be a trick somewhere), I started cross-checking the pins. I saw that some pins are short circuited. The ones I was able to discover was all ground pins. Like the return pins for R,G & B. But they were not short circuited with the casing ground. So I believe this cable cuts corners by using the same wire for some ground pins.

The bottom line is; if you are going to buy it, test all pins to be safe. If you want to build it yourself, the first option is using a full wire set cable. But this has it's disadvantages as the cable would be thick, hard and heavy, putting too much pressure on the connectors of your TV and laptop. The second option is cutting corners like the cable I have does, but the problem is I really don't know which grounds are short circuited (share the wire) and which ones are not. My multimeter still has not arrived and I borrowed a very bad one to do the checking, so if you are gonna do this, do it at your own risk...

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But the "non-working" cable works with others monitors...???
by budwich / December 21, 2008 1:17 AM PST
In reply to: Yes, exactly

From what I can figure is that the nonworking cable (no ground pins connected even to the casing) works with a couple other things in the house, dell monitor and optoma projector.... so their (other monitors) "in board" design must make use of the casing continuity that exists in the "non-working" cable to "grab" a ground return for the rest of the "stuff". In your example, just one "ground return" is needed to cause this "goodness"... and it has to show up in the cable pins themselves as opposed to expecting the "inboard" design to accommodate it (ie. couple the casing to signal ground returns). Ultimately, I think its a bad design by cable manufacturers to use case grounds as signal ground returns... which may couple in all sort of noise into your circuit.

BUT there is also more to the story than that... as I mentioned, because the "good" cable that has all pins "properly connected" works differently than another "good looking" cable that I have that has all pins connected but no pin 9 (physically missing in the connector)... The samsung TV can't detect this "good looking" cable either.... yet because this cable is an extension cable (ie. male end and female on the other), I can add on my good working cable and the TV "detects" the combination (again without a PC at the end) while if I use my "nonworking" cable in the combination (good looking plus non-working), the TV will not detect it, something very strange and not meeting the "eye".

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samsung and vga cables
by budwich / December 21, 2008 7:58 AM PST
In reply to: Yes, exactly

well I spent a bit working thru this... basically I performed a "doctor kildare" on one end of my "non-working" cable... split the casing to expose the wires... ugly but that's all I had around. I then ran a wire from pins 6,7,8 to the casing... in essence, connecting all the rgb grounds (that had no connection wires) together with the casing (which was wired end-to-end). the cable still didn't work. I rechecked my working cable and found that pin 10 (sync ground) was also "casing connected". Re-did my wiring to also include pin 10 in the multiple ground pins to casing connection and viola, the cable is now recognized by the Samsung set. IF you make up a little "doggle" with a female and male connector (then you would have to play doctor), it can be used to make a non-working cable work with samsung. Basically, pins 1,2,3 (red green blue signals) are run straight across along with 13 and 14 (sync h , v signals). Then at the male connector (assuming it is mating with your samsung monitor), connect /multiple pins 6, 7,8, 10 (signal grounds) to case of the male connectors. Run a connection from one casing to the other. That's it. Plug the male "doggle" into your monitor and plug the female end into your cable and voila. Hope it helps.

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How about windows recognition?
by CemAygun / December 27, 2008 7:36 PM PST
In reply to: VGA Problem Revisited

Well, thanks a lot for totally solving the case Happy But I would like to ask something else also. How does your windows recognize Samsung TV with the "hacked to work" cable? Because with the bad cables, maybe because I cannot turn on the PC mode, windows recognizes the TV as "default monitor" and enables output on it (although I can never see it as TV does not recognize the PC)

With the good cable, the TV is recognized as "Plug & Play Monitor", and all the supported modes are listed correctly. So I assume there is some other wire going through with the good cable, but I am not sure...

And by the way, if I am not mistaken PC can also put the monitor into sleep mode.(or it just disables the signal and TV goes into sleep mode automatically, I really don't know)

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samsung and VGA cable
by budwich / February 2, 2009 1:16 PM PST

Sorry I thought that this thread was "dead" and also I was / am on holidays... Happy so my answer to your query may not be exact as I don't have access to my setup and won't for a ~month.

Anyways, just prior to leaving, I got a dell mini9 and hooked it up to the TV with the "adjusted" cable... works fine.

Back to your question about windows, basically, for the mini9 (which is the last thing I saw / remember), windows automatically set the resolution at 800X600 but I am not sure why per se as the display on the mini9 is 1024X600 but the 800X600 seemed more "appropriate"/ normal for a terminal / monitor. Probably somethng to do with defaults (PC) in the samsung design. If I remember right with my higher resolution laptop (gateway 15in), the display seemed to want some resolution that was not supported (error displayed - "mode not supported"). I can't recall what it was trying to select from the laptop side but I think it was some form of xxxx X 7xx. If I recall correctly, I could "force" the higher resolution (1xxx X 1080 and I may have some of that wrong) by selections from windows. However, that aspect on the TV was stretched (wider than I expected) so I wasn't sure what I was getting although the status connection label on the TV did indicate that resolution (IIRC). There is some "funnies" as my son tried his MAC laptop with a "good cable" and display was shifted right and the aspect was "unusual". Sorry, I can't be more accurate... but if you are still interested, I will retry things once I get back home.

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Plug-and-Play Video With Intel Graphic Chipsets
by Gene Cook / January 26, 2009 1:27 AM PST
In reply to: VGA Problem Revisited

I'm a product manager for a company that makes AV switches and AV distribution equipment. I found this thread trying to solve a problem where a desktop PC with an Intel 82945G Express Chipset could not access the native display resolution (1366x768) on a Samsung 400PX display _using our company's_ VGA signal extender.

Here's my take on this thread -- if your VGA cable doesn't correctly pass the DDC signal on pin 12 you may not be able to display a high definition signal from your computer to your monitor.

On a related note, when you use our VGA signal extender, it also doesn't pass the signal on pin 12, causing the same problems that one sees when using a "bad" VGA cable.

Here's a link on the Intel site that has some suggestions:

Has anyone out there experienced problems with Intel Graphics Chipsets and HD displays? Has anyone tried the suggestions from the Intel site above?

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by Samsung_HD_Tech Samsung staff / January 26, 2009 11:23 AM PST

Mr. Cook,

Thank you for jumping in on this.

Many of the BIOS updates reassigns pin 12 to do just that, particularly on one brand of computers. I'd be interested to know if that information might help your situaton as well. Even an extender should be able to pass an active Pin-12.

Obviously I can't explain how to reassign these pin numbers but manufacturers are catching on. I'll read up a little more, but wanted to thank you for your initial contribution.

Hooking up laptops and computers to PCs continues to be frustrating for many of our members. It could be the pin structure, it could be resolution, it could be that the compuer isn't sending the signal out via the external VGA... there are a lot of factors in the equation and it seems that every one of those solutions helps one person, and not the other.

Keep me posted, and welcome to the forum!


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Yes, a quality cable makes a difference
by zipityzap / January 27, 2009 3:42 AM PST
In reply to: VGA Problem Revisited

I've heard of many cases where the "pc input" mode on Samsung TVs are "greyed out." Your HDTV may only let you select modes that are being detected. When shopping for a cable, search for a cable that has specifically been tested for PC to TV applications and comes with a money-back guarantee.

I have sucessfully used both a VGA and HDMI cable on my 32" Samsung HDTV. Contrary to what others have said, both cables provide excellent picture quality:

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samsung and vga cables
by budwich / February 2, 2009 1:38 PM PST

Actually, from my "testing", what you hook to the TV (at the other end of the cable) has nothing to do with it at all! With a "good cable" plugged into the TV and NO device plugged into the other end, the TV readily "detects" something and "instantly lights" up the previously greyed out PC optioned input. Without that "detection characteristic", no amount of "mode signalling" is ever going to work since the TV "thinks" you have no cable connected to the input.... so I don't believe, at least in this thread posting, that pin 12 at the PC or resolution mode is involved.... it is some kind of "layer 1 physical protocol / idiosyncrocy" with samsung at least.

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samsung and vga
by budwich / February 16, 2009 3:37 AM PST
In reply to: samsung and vga cables

Probably need to put some additional comments around the grounding. The grounding can come from the "far end" (ie. the connected computer). It appears that some implementations / "handshaking" on some computers (maybe dell) causing the output on the computer to "connect / switch" the grounds together. YMMV with this form of operation from what I can see.

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Ground Pin Problem?
by TODRI / February 26, 2009 9:30 AM PST
In reply to: samsung and vga

budwich - you are one of the few people who seem to understand this problem. I have a Samsung LN-T4061F. I was able to connect a Lenovo PC via a VGA cable no problem. However, I just got a new 13" Macbook, purchased the 29" mini display to VGA adapter and have no luck getting the display on the tv. The Macbook recognizes the Samsung, and the Samsung "hiccups" when I change the display settings on the Macbook (the screen on the Samsung jumps a tiny bit), but I can't get it to work.

So do you think it's still a grounded pin issue even though my VGA cable works fine with the PC?

Also, have you found out anything more? Any VGA cable recs? I'm not much of a MacGyver when it comes to messing with cables.

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mirror mode?
by zipityzap / February 26, 2009 9:48 AM PST
In reply to: Ground Pin Problem?

Did you enable your "mirror mode?"

Setting up Laptop (Mac):

Set your desktop resolution to either 800x600 or 1024x768 and enable "Mirror" mode.

Click on the Apple menu.
Select "System Preferences."
Click on "Display."

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Mirror Mode
by TODRI / February 26, 2009 10:41 AM PST
In reply to: mirror mode?

Thanks for the suggestion. I tried that before, but then tried it again with your specific resolution recs and it didn't work. Interesting thing I realized though: when just the VGA cable is attached to the tv, I cannot access the PC input from the Samsung menu->input display (it's greyed out). However, once I attach the mini display to VGA adapter to the VGA cable (BEFORE I attach it to the Macbook), the tv lights up the PC option in the input section of the menu and I can choose the PC input. Once I choose the PC input like this, a dialog box says "searching for signal". Once I hook the mini display into the Macbook, a new message appears on the tv and says "check signal cable". The fact the tv recognized the mini display to VGA adapter without the Macbook (not to mention the fact that the VGA cable works with my PC) tells me the VGA cable is not the problem and maybe it's the Macbook maybe? Any thoughts?

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No Luck
by TODRI / February 26, 2009 10:53 AM PST
In reply to: Mirror Mode

btw tried every available resolution setting (my Macbook definitely recognizes the tv because it calls it "Samsung" in mirror mode and offers more resolution options), but no luck.

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vga and samsung
by budwich / February 26, 2009 12:53 PM PST
In reply to: Mirror Mode

Well, I think you probably need to verify your adapter. From this post, you indicate that the combination of your cable plus the adapter "lights" the PC mode option on the samsung. That's good. It would appear that you aren't getting signal thru in some form... probably signal level. You probably need to try the combination with a non-samsung tv/monitor (borrow, beg, "steal").

Small question, when you used just your cable and your PC, what was the status of the "pc mode" on the tv (ie. when does it go from "greyed" to "lit")? Do you notice when it changes?

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VGA Samsung and PC works
by TODRI / February 26, 2009 7:43 PM PST
In reply to: vga and samsung

Thanks budwich. I just tried the PC. When the VGA cable is plugged in to the Samsung with no computer, the PC option is greyed out. As soon as I plug in the computer (even before I hit "Fn->F7" to export the signal as you do on a PC), the Samsung recognizes the PC. In other words, before the Samsung is truly getting a signal from the PC (it says "searching for signal") it at least allows me to select "PC" from the input menu. The Samsung knows something is up.

I will try the Macbook and the VGA adapter this morning with the projector I have in my classroom at work which I know works.

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Mini Display Adapter Works
by TODRI / February 26, 2009 9:08 PM PST

The mystery continues. Checked the mini display to VGA adapter with my Macbook on a projector at school and it works fine.

So.... back to suspecting the cable/Samsung compatibility? Even though the VGA cable I have at home works fine with my PC? Ughhh.

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samsung vga and miniadapter
by budwich / February 26, 2009 11:16 PM PST

I just hooked up a macbook pro thru the adapter and my "modified cable". Everything is fine... of course, my samsung tv is not the same model but I just wanted to verify its operation. The other difference in my setup is that for my cable, when it is plugged into the tv, the "pc mode" is "lit" instead of being "greyed". This is without anything attached to the other end. You only get that "state" when your doggle is plugged onto the cable. My cable is very "simple", only 5 pins are connected end to end (IIRC) plus one ground connection (sheath).... of course, all the grounds are connected to that connection.... and no pin 9 (removed). Perhaps, you can check yours with a meter. Of course, we are dealing with different samsung units which could be the ultimately be the problem but since your PC works with it, I would say its a "compatibility" issue and not a "hard fault" especially since the setup works with the projector (good test). One other thing, is that with the mac, my tv picture is "offset" to the right like it is "mis-synced" where as with my PC, the picture is centered. I can only adjust the picture via tv controls a bit but not enough to center the display. Not sure that I have helped much... Sad

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vga, samsung, and mac adapter
by budwich / February 27, 2009 8:05 AM PST

I took a look at the dvi-a spec which shows only rgb pins plus a horizontal sync pin... the only analog ground is the connector casing. Measuring the mac adapter, confirms that those are the only things connected... hence no grounds for the rgb and the casing ground IS NOT connected to any of the ground pins in the vga connector end of the adapter. Soooo, I am not sure why your samsung "detects" the cable with adapter added???? My samsung TV would not detect the "unmodified cable" (ie. without the grounds connected) with the adapter. Possibly, just the "leakage" or "float level" of the signal is enough to "trip" the "greying" but not enough for operation thereafter. My cable is 15 feet long (length might have some bearing) and have no problems as the image is very good. If possible, can you determine what pins on your cable are connected end to end (without the adapter)? Also along a similar manner, with the adapter attached, verying conntinuity end to end (quite easy with a meter and look up of pinouts for dvi-a and vga).... maybe you have a weak pin connection somewhere.

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