Help with DP to DVI Adapter, can't get signal.

tel1jag

Limp Gawd
Joined
Apr 29, 2002
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136
Hoping someone could give me some ideas as I have been racking my brain on this one and so far nVidia and Asus support have nothing.

Built a PC for my son to run his VR kit (HTC Vive) gave him my current computer parts and rebuilt/upgraded mine.

It's an Intel 6700k, 8GB Corsair, SSD drive and a WD spindle drive. The video is ASUS STRIX-GTX980-DC20C-4GD5. It's got 3 Displayport, 1 HDMI and 1 DVI port. He has 2 older monitors that support DVI and VGA. So, we have 1 monitor in the DVI port and that works fine. His VR is taking up the HDMI port and works fine. However, we can not get the 2nd monitor to work using an adapter from DP to DVI. I first bought a passive one because I thought the card could support DP++ but in CHATTING with nVidia they said I needed an ACTIVE one, so I bought that. However, regardless of which one I use I can't get a signal on the monitor. I know the monitor works because if I switch the actual DVI port to either of them they work fine. I know the DP ports work because I was using 2 of the ports for my monitors (which can go natively to DP) and this is with trying first a passive adapter and then an active one. Reboots, trying to detect the monitor, etc. and it does not see/get a signal from the adapter.

Any thoughts? nVidia and Asus were not able to give me any answers.


Thanks!!!

--Jeff
 
could be a faulty adapter.
I have one and it just works.
 
You will probably keep buying expensive adapters till you doing one that works. Those things are horrible. Better off buying a used DP display.
 
Which adapters have you tried already? I'd like to take a look at the specs on them if you don't mind. The main issue with DP to anything is convincing the DP that the port is in use and the monitor is on, since DP disables the port when a monitor isn't detected. That's likely why they wanted you to have an active adapter (DP Active adapters also come in 2 flavors... Active, and Active Powered. Active is powered by the DP itself, and Active Powered uses an external USB connection for power)
 
Which adapters have you tried already? I'd like to take a look at the specs on them if you don't mind. The main issue with DP to anything is convincing the DP that the port is in use and the monitor is on, since DP disables the port when a monitor isn't detected. That's likely why they wanted you to have an active adapter (DP Active adapters also come in 2 flavors... Active, and Active Powered. Active is powered by the DP itself, and Active Powered uses an external USB connection for power)

Johnathon...thanks for your reply.

The passive one was:
https://www.amazon.com/gp/product/B013PWJKQ4/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

The active one was:
https://www.amazon.com/gp/product/B06W2FZ9MK/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

The active one is not powered. Your response makes a lot of sense on what I am seeing. I wonder why anyone would buy the non-powered active or passive (other than the mistake I made, then) or how all these people on the first one have given it high ratings...very strange.

If you feel a powered active would fix this, I'll buy one I guess, but at $100 or so...seems like buying a Dell (like the U2415) or Acer monitor or something than only becomes another 100 to 150 more?

Your thoughts Johnathon?

--Jeff
 
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In all honesty, I'd probably go with the monitor over the adapter. Like Kyle said, these adapters are all pretty iffy in terms of functionality, especially in the long term. The new monitor would probably also give you better picture quality and will last much longer than an older monitor+DP adapter.

The U2415 is also cool because it has DP Daisy Chaining, so if your son ends up liking the monitor and the other one dies/etc. you can buy a second one and connect them together without having to worry about extra ports on the video card in the future. I actually use 2 of these for my work monitors daisy chained together at 2k resolution and it's great. Much easier cable management as well when you do that.
 
In all honesty, I'd probably go with the monitor over the adapter. Like Kyle said, these adapters are all pretty iffy in terms of functionality, especially in the long term. The new monitor would probably also give you better picture quality and will last much longer than an older monitor+DP adapter.

The U2415 is also cool because it has DP Daisy Chaining, so if your son ends up liking the monitor and the other one dies/etc. you can buy a second one and connect them together without having to worry about extra ports on the video card in the future. I actually use 2 of these for my work monitors daisy chained together at 2k resolution and it's great. Much easier cable management as well when you do that.



Thanks. I was thinking about your comment about the DP port not sensing enough power draw and turns off...is there a way through settings to tell it not to turn off? I am still totally confused how those units could have gotten good feedback on Amazon so far unless other cards do a better job not turning off those ports? The motherboard is a Sabertooth X99 and pretty configurable.

--Jeff
 
Thanks. I was thinking about your comment about the DP port not sensing enough power draw and turns off...is there a way through settings to tell it not to turn off? I am still totally confused how those units could have gotten good feedback on Amazon so far unless other cards do a better job not turning off those ports? The motherboard is a Sabertooth X99 and pretty configurable.

--Jeff

None that I'm aware of on any board I've seen. I have a similar issue in that I run a dual monitor setup and prefer my taskbar not be on the "primary" monitor. Unfortunately, every time I turn my monitors off, the "main" taskbar is moved to the primary monitor again because the monitors are DisplayPort. There are ways to disable the detection, but not for the GeForce series of graphics cards. You'd have to have a Quadro workstation card to get those settings, and even then they're monitor dependent and would fix my issue, but not yours. (This is how nVidia sells workstation cards, they offer more robust software with additional settings in the control panel that would actually benefit everyone, but that we can't have!)

And to speak to the other reviewers having success: There may be a couple of explanations to that.
  1. Paid reviewers are a serious problem on Amazon. People get a code to buy the product cheap/free in exchange for reviews that paint the product in a good light.
  2. Their specific setups allowed for it to work. Though I'm not really sure in what scenario it would work, unless some graphics cards send out a different signal type over the DP to try to talk to converted monitors, which would be weird.. So, in your specific setup it isn't working because the signal that the monitor exists isn't getting sent to the graphics card. Really, it's actually more of an issue of the data that's getting sent isn't the "correct" data. HDMI and DVI used TMDS and DisplayPort does not, it actually uses packets like ethernet does to send the data to the monitor. The cheap adapters move the data to the correct pins, but they don't de-packet the data so that the two devices can talk to each other in the same language. The expensive adapters include a chip that converts the packets to TMDS for transmission to the monitor. That being said, none of those expensive adapters seem to do it well, which is what Kyle was speaking to. They all suffer issues with handling power cycles and such of the monitor, and sometimes have to be unplugged and plugged back in to get them to work again. It's super annoying and not really worth the hassle.
 
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If you decide to try more converters this one is a good one to try: http://www.aten.com/global/en/products/professional-audiovideo/converters/vc965/

That company makes high end KVMs, and low end ones too. They're one of the few brands whose KVMs aren't flaky. Seems like they know their way around the sticky details of display interfaces.


Thanks BecauseScience, however, given what Kyle and Johnathon have said and explained and my experiences of using both a passive and then an active (but not powered) adapter, I'm guessing that one won't work with my setup either. Whether it's the GTX980's specs or the Dell monitor, I have a feeling I am going to see the same result (which is nothing). There was nothing on that page text or diagram-wise that leads me to believe they can help me in my situation. If there was somewhere on there that said "we can do the problematic nvidia 9 series or those PIA dell monitors" (obviously it wouldn't have had to be too specific, but something that showed some experience in what seems to be a complex series of signals) then I think I would have gone one more round. Now I think I am sold on fixing this utilizing a DP monitor.

However, I do appreciate the suggestion...thanks for that.

--Jeff
 
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