Will a long run of VGA cable and/or using a splitter damage VGA card?
October 17, 2013 6:07 AM   Subscribe

We've cooked a video card that was 1) supposed to be at least somewhat high end and 2) was hooked up to a VGA splitter, with one leg going 100' to a monitor. Coincidence, or did we overload/cook the video card?

Disclaimer: I am not the lead decision-maker on how this system was put together. I'm sparing the editorial comments as much as necessary, because in several ways I'd have done this differently.

What have we got? It's a PC with low-end "gaming" video card which has VGA, DVI, and HDMI outputs. I think it was made by NVIDIA; regardless it's a name-brand card we paid about $70 for at Best Buy, not a bargain-basement card. We've put a fairly heavy duty power supply in the PC (500+ Watts). Otherwise, PC is nothing special. Running Win 7.

PC is in back of building.

HDMI cable makes about a 100' run to projector mounted overhead in auditorium.

VGA goes to splitter; one side goes to monitor which is right by PC; other makes 100' VGA cable run to pulpit for second (duplicate) monitor so minister can see Powerpoint presentation mode while audience sees presentation on projector. Display on pulpit monitor is a little fuzzy and a slight scan line "ghost" has been seen sometimes, but it's passable for the purpose intended.

So what's the problem? We'd been running in this mode for about a year when one PC set up this way had the video card die. A replacement video card wouldn't work; we decided (whether accurately or not I don't know) that the power supply didn't have enough power for the card, and the power supply couldn't be upgraded in the PC we had, so we bought another PC with a more standard case and heavier power supply. We had several driver problems with the video card, so we replaced it with the Best Buy aftermarket one.

It died in about 3 months (no VGA output; HDMI still worked), and I've replaced it with a similar aftermarket video card.

Obvious implication is something's happening to the VGA cards. To confirm what seems almost obvious - would a long run of VGA and/or using a splitter add an electrical load to the card that would cause it to have an extremely shortened life?
posted by randomkeystrike to Computers & Internet (10 answers total)
Response by poster: One more clarification: none of the cards have been found to have obviously scorched components. My question begins "We've cooked..." which begs the question.
posted by randomkeystrike at 6:09 AM on October 17, 2013

My first guess would be that your VGA cable itself is physically damaging the VGA socket, and that the damage would happen even if the setup was unpowered. I've had a number of HDMI and VGA cables that deformed the sockets on PCs because they were too heavy or cheaply made.
posted by Jairus at 6:30 AM on October 17, 2013 [1 favorite]

Unlikely. Could be. 100 feet of antenna. Transients from lightning strikes, etc. Is the splitter active or passive? If it's passive, it's presenting a nominal load to the source and the source should not care what happens on the other side of the splitter (with the exception of transients, like lightning, where the gentle rules break down and all bets are off.)

Here is an active VGA extender that ships video via CAT5. You may want to use this type of cable for that distance. Signals are differential and transient robust.

Not sure if VGA specifies length max of cable. It's 15 wires, though. You will have interconductor capacitance issues, signal loss (though not much), reflections. It's installation specific. It would never occur to me to order, build, buy a 100 foot VGA cable. Haven't a clue.

You can continue to guess. You can also get more specific. Do the cards go dead? Or does one VGA color go away. Same color each time? Any Sync signals? I2C activity?

Scope time, bud. Find a tech who can run one and tell you what's dead on the card. Post question again with better detail and you may get a better answer.

Meanwhile, a modality built for distance might save you from having to answer "why" in favor of ruling out one possibility.
posted by FauxScot at 7:08 AM on October 17, 2013 [1 favorite]

$70 could be a bargain-basement card, if it wasn't an older card on clearance. If it's a cheaper card it may have simply failed. Flashy gaming-related box art doesn't change that. Also, you don't need a gaming card, per se. What you really need is two digital outputs, so you can use HDMI for your pulpit leg as well, plus another output (digital or analog) for the display at the CPU. And it sounds like you want to avoid the newest cards, which use DisplayPort and will require adapters for older displays.

I'd suggest this. It's a cheap Radeon by Sapphire. Has an HDMI, DVI and VGA port. You can use a DVI to HDMI cable for either the projector or pulpit display.

It's $24 -- buy two and throw one in the cabinet.

Here's an alternate $30 option from Asus with slightly better specs.
posted by snuffleupagus at 7:11 AM on October 17, 2013 [1 favorite]

Also, if you do want to go the "correct" route, then it would be a workstation video card. Here's a modest $150 option from AMD. It only comes with one DisplayPort adapter, it would seem, so you would likely need to buy a second.
posted by snuffleupagus at 7:17 AM on October 17, 2013 [1 favorite]

Given that its sounds like your current replacement card is still functioning, if it also has VGA, DVI and HDMI outputs, you can stop relying on the VGA port by getting an HDMI matrix switch (often just called a splitter in the 1x2 configuration). Then feed either the projector or switch with a DVI to HDMI cable, and connect the CPU and pulpit displays to the HDMI 1x2 matrix.

Here's a pigtail version from Monoprice, and box type. Both about $32. You may need to use another amplifier or repeater on the way to the pulpit. Here's a $12 offering from Monoprice.
posted by snuffleupagus at 7:32 AM on October 17, 2013 [1 favorite]

If the card is damaged electronically, I'd be looking for ground differentials, or seeing if the projector and computer are on different legs of the building power.
posted by tomierna at 10:14 AM on October 17, 2013 [2 favorites]

Yeah, could be a ground loop, or pickup of damaging transients, although the fact that the HDMI run is fine discourages the latter idea. Could be bad VSWR on the VGA cable, leading to overvoltage at the VGA card which eventually kills the output driver. The computer power supply is not really relevant.

You could always put two video cards in the same computer, if one card doesn't give you the right mix of ports. I think most modern drivers will let you mirror to all displays, though I'm not 100% on that.
posted by Standard Orange at 4:05 PM on October 17, 2013 [1 favorite]

Response by poster: to address some of the questions or to clarify - the card was made by Galaxy, which appears to be an NVIDIA brand. Got it on closeout at Best Buy. I tended to end up with gaming components because it was what I could get locally on the shelf and the thing always seems to fail (or I'm told that it's failed) at a point where I had to try to get it running before a service which was <2>

On the first failure, EVERYTHING died. On the more recent one, only VGA died, and apart from some sputtering moments where it gave display, it was just blank-screening the display.

The splitter - I'm not sure if it's active or passive. It's a box type, rather than a Y-cord type, but I can't remember if it's got a power supply - that's something I'll need to check on. If it's passive, that's occurred to me as likely contributing to the poor image quality, if nothing else. The system only recognizes it as one monitor, so I think it is passive.

Given that the cable runs are in a high part of the building, and the equipment itself is in an attic/loft type space, I think the idea of power, grounding, or VSWR contributing to the problem seems likely, and the drift of the answers is that the 100' run itself doesn't seem likely to be causing a load.

While I hate the idea of climbing around and running more cable, it seems to me at this point that we need to use a VGA repeater, run some Cat 5 cable, and do this VGA run more correctly. And look over the grounding situation more carefully.

Thanks for all your answers!
posted by randomkeystrike at 5:41 PM on October 17, 2013

This HDMI extender is cheap and has the best reviews of the extenders on Amazon. It's especially neat that it's powered off the HDMI! Requires CAT 5e/6 cabling.
posted by wnissen at 6:48 AM on October 18, 2013 [2 favorites]

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