Home Theater Forum and Systems banner

Help - DVI signal from PC gets dropped by TV

6497 Views 36 Replies 4 Participants Last post by  Otto
Hi there,

I have a problem with my HTPC video signal. The connection goes like this:

ATI Radeon x600 DVI output --> MonoPrice 3x1 HDMI Switch --> Panasonic Plasma

From the video card to the switch, I'm using a DVI to DVI cable with a DVI to HDMI adapter at the switch end. From the switch to the TV I'm using an HDMI to HDMI cable.

I'm also switching a Denon DVD player and Dish Network DVR through the the MonoPrice HDMI switch, and they have no problems.

In general, the PC works OK -- I can use the TV as a monitor, watch DVDs, etc. However, sometimes when I turn on the TV and select the PC as the input, I will get no picture from the PC. I have to go to another PC in the house to remotely shutdown the HTPC. Once it comes back on, everything is fine between the PC and the TV. All connections are good, proper inputs are selected, etc. It's just that after a while (I don't know what "a while" really is, but let's just say a few hours).

If everything is working, I am able to switch between the Dish Network signal and the PC, so it's not just a matter of switching to a different input and not being able to go back to the PC.

Any ideas? I'm not an HDMI/DVI expert, so I'm not sure what the problem is. I think there's some handshaking going on at each connection point, so I'm not sure what the point of failure is. Is it the PC, the switch or the TV?

I've ordered a new HDMI video card, as recommended here. The ATI I have now has been problematic, and ATI drivers are the worst I've seen. I've heard good things about the GeForce stuff, so hopefully it will help. It should arrive today or tomorrow.

So, any ideas on what could be the problem?

1 - 20 of 37 Posts
It sounds like a handshake issue. Have you tried turning on the PC before turning on the TV?
Hi Mike,

If I have the TV on, and then turn on the PC, it's fine. The PC then remains on 24/7. At that time, I can then switch back and forth between Dish/PC/DVD and all is OK.

The problem arises later in the day. Suppose I want to come home and watch something on the PC tonight -- that's when I have to reboot the PC. I don't even think that it has to be switched away from the PC. But when I come back in the evening it just won't display to the TV.
""sometimes when I turn on the TV and select the PC as the input, I will get no picture from the PC""

Otto, If the TV is on and working with the dish or DVD, turn off the TV before you select the PC. If the problem is caused by the TV handshake, that should be a solution. I have the same issue with a Sony Bravia.
Yeah, I've done that too. For example, the PC is selected at the HDMI switch, and the TV has "HDMI 1" as its input (the input to the TV itself never changes; I only use the one HDMI cable to the TV). Then, when I turn the TV on, still nothing.

In fact, I could do something like this: watch PC on Monday night. Turn off the TV when I'm done, but the PC stays on. Come back on Tuesday night and turn on TV (PC is still on and HDMI switch is still on PC). No picture on TV with PC input.

I need to try to continue to narrow in and be 100% sure of these steps, but I'm pretty sure it's accurate in the way I'm describing it. I also plan to remove the switch from the path and see if it fixes the problem. New video card should also be here soon, and I really, really hope that solves the problem.

Thanks for the ideas! Keep 'em coming!
When you say the PC is "on", do you mean no screensaver, no sleep mode and no hibernate?
Right, no screensaver, no sleep, no hibernate. However, we commonly "Remote Desktop" from other PCs (to control audio only) and the screen simply goes blank. I think it also goes blank even if we are not using "Remote Desktop" -- but I'm not 100% on that; I rarely leave it on long enough to go blank. Thinking it over, I guess it's possible that we could consider a blank screen a "screensaver."

Let us know what the results are when you eliminate the HDMI switch. I'm really curious to find out what the problem is here.
Yeah, I'll work to reliably repeat it. If I can get it failing by using some known sequence in, say, one minute or so, then I should be able to narrow it down pretty quickly.
Well, things had gotten A LOT better since installing this video card. I really thought things were fixed, as I had not received a "nothing" screen at all. Then, last night, I get a "nothing" screen. I go through the reboot process remotely, turn the PC off, then power back up. I get the BIOS screen and the "Windows" screen, but as soon as it goes to the main Windows login, it goes black. I can login remotely, and the PC is working fine, but I get nothing at the TV. Ahhhhhhhhhhhhhhhhhhhhh! What an annoyance!

I'll try to figure out what's going on with this card. Still, I'm convinced that the other card (ATI x600) was junk. No surprise: I have always had problem with ATI video cards.
Fixed the GEForce card's output by uninstalling and reinstalling drivers. I got the latest from the website, so hopefully they've gotten than bug taken care of. Actually, I bet it was a lingering part of the ATI drivers that are still out to get me... :devil:
At least things are getting better. Hopefully you'll get it all worked out.
Hi there, Mike P and anyone else who might be able to help!

Still using the XFXForce 7600 GS card with HDMI output. Every once in a while, the video output will just disappear, and then I have to reinstall the drivers before it will work again. Tonight, in an effort to ensure that it's not "something else," I reinstalled Windows XP Media Center and then installed the drivers. I didn't install any other drivers or software. As soon as I switched to "Dish" on my Monoprice switch and then switched back to "PC" the video output no longer worked. The DELL and Windows "splash screens" show up (so I know the switch and cables are working) but once it comes to the time to get a mouse cursor and XP logon, I get nothing.

At this point, I will have to reinstall the drivers again for it to work. Lame.

I have also taken the switch out of the equation, plugging the HDMI cable directly from the video card to the TV.

Now, imagine that I have everything working (drivers installed, display OK, etc.) and the video card is connected directly to the TV (i.e., no Monoprice HDMI switch). If I simply unplug the HDMI connection while the PC is on, it will cause this situation apparently 100% of the time. Yep, if the PC is on and working and I pull the HDMI cable it will cause me to have to reinstall the nVidia drivers before things work again at all.

Also note that once this occurs, I cannot use the DVI or VGA (via DVI to VGA adapter) output of the card. I can't view anything on a regular old VGA CRT. It's like the video card isn't there.

Has anyone ever seen anything like this? It's driving me nuts and really precluding use of my HTPC. I have to reinstall drivers almost every day. Since I just did a fresh install and I didn't enable Remote Desktop, I can't quickly reinstall drivers and reboot from another PC. Think I'll reinstall Windows again rather than drag up an old CRT monitor, enable on-board video, etc.

I will say that XFXForce support has been pretty good, and the last thing that they suggested was a clean install of XP. I've submitted my results (as above) and will see what they say tomorrow...


Please just work!!!!!!!!!!!!!!!!!
See less See more
Since you've narrowed down the possibilities, it sounds to me like this is a video card problem. Any chance of swapping the card out with another one?
I have, I think, the same problem. The specs of my machine are:

Vista Ultimate 32
Intel Core 2 Duo E6750 / 2.66 GHz
2GB PC2-4200 DDR2 DIMM Memory (533) - had on shelf and plan to replace
GeForce 7600GS 256MB HDMI 400M DVI DDR2 PCI Express
Auzentech HDA Digital X-plosion 7.1 DTS Sound Card
Gigabyte GA-P35-DS3L
Zalman HD160B

I have the HTPC and a Comcast HD DVR connected to my AVR-1508 Dennon Receiver with HDMI cables. The Dennon is connected to a 50 inch Panasonic 720p plasma with a single HDMI cable. In theory, I should be able to use the receiver to switch this way. Every time I switch to the HTPC (always on, no sleep, so hibernate, no screen saver, plain blue background with no icons), I get a black screen. I can restart in safe mode, delete the Nvidia driver, restart and re-install the driver and it works fine… until I switch to the Comcast set top box and back to the HTPC… black screen again.
I figure that this was either (1) a hdmi handshake issue (2) the switching function of the Dennon (3) some vista corruption resulting from my ‘tuning’ and configuration attempts. I eliminated #2 by taking the Dennon out of the equation. The issue occurs if the HTPC is plugged directly into the TV.

My next step was to reinstall Vista and see if the problem still exists. Please post what the XFXForce tells you…

See less See more
Hi Andy,

Wow. Someone finally understands my problem. I sent the video card back to XFXForce. They said it tested fine, and they said they swapped my card anyway to help me troubleshoot. I can't verify that since I didn't write down the serial number, but let's just suppose it's true.

Can you do the same thing that I described above? Just have everything running and working, and unplug monitor cable from the video card. I think I described it above, but I've done it with the plasma TV as well as a flat panel analog PC monitor (DVI output -> DVI to VGA adapter -> VGA monitor). Same thing. Everytime I unplug it, I have to reinstall drivers.

The new video card I received from them does the same thing.

I was using Windows MediaCenter, so I thought maybe that was the problem. I installed XP pro and have the same problem. I have tested this with no other hardware in the system, with fresh OS installs and the same thing happens everytime.

So, what remains to be the culprit?

1. Motherboard
2. RAM
3. Hard drive
4. Power supply
5. Processor

I was most suspicious of the motherboard. Last night, I did some research, and I think I've decided to buy the same motherboard you've listed (the Gigabyte). However, before I do that, I'm going to test it on another system to which I have access (Dell Precision 390). I'm assuming it has a PCIx16 slot that I could use. I will see how that behaves.

Another reason that I'm suspicious of the motherboard is that I have problems with the original video card (some ATI junk). It's not as bad as the nVidia, but I do have to sleep->awake or reboot every once in a while. Also, I find the ATI drivers and software to be poor, so that's a constant source of annoyance (e.g., I can't resize my desktop at all right now because CCC won't execute. Never again with ATI for me!).

To find that you are having the same problem with the motherboard I thought I wanted it discouraging.

I think you should also contact XFXForce. Although we have not come to a resolution, I will say that their tech support has been very helpful. My ticket number is 124758, if you want to tell them to reference that. I will PM you the whole thread between them and me, and you can see what they came up with.

If we can resolve this with the video card vendor, that would be great. I will be really bummed if I buy a new motherboard and it's the same thing.

Thanks and good luck!
See less See more
I can restart in safe mode, delete the Nvidia driver, restart and re-install the driver and it works fine
Oh, I forgot to mention that you can probably skip the deleting the nVidia driver. I just reinstall the drivers and it works OK. I can also do this from a Remote Desktop session in order to skip the Safe Mode boot.
Does anyone have a friend that has a different type of HDTV that they might allow you to connect your PC to? IT sure sounds like a handshake issue but maybe it's a brand of TV handshake issue? Who knows how it's wedging the SW/HW config...

For me, I used both the plasma and a regular Dell analog flat panel monitor. Same thing in both cases.
Otto –

I have created a ticket with XFXForce yesterday and referenced this string. I will also try the direct connect / unplug idea, but won’t be home until tomorrow evening… I plan on doing this before and after a fresh Vista install and will post the results.
Thanks for sending the details from your support ticket. I haven’t had the chance to review yet, but will soon.
I don’t think it is any of the other items mentioned… My setup was working fine on my old planar plasma. I was, however, switching back/forth from digital to analog (DVI to RCA) – not digital to digital. Since then, I was trying to get a QAM signal with an Aver card, so I can’t be sure that process didn’t mess things up. I plan to try the direct disconnect on the old planar too… it doesn’t have HDMI… just a single DVI… so I can’t test the digital / digital. I happen to also have a 42” version on the Panasonic (same product family as mine) still in the box. I may try that too. I think that if the same thing doesn’t occur on the planar, it has to be either the handshake with Panasonic or a video driver issue.
The two items that our setups have in common are the Panasonic TV and the card. My TV is model TH-50PC77U… what is yours?
Otto, PM me your email. I don’t have enough posts on this site to get PM privs yet.
See less See more
1 - 20 of 37 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.