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4 HDTVs flickering using PC-to-TV connection

Tags:
  • TV
  • PCS
  • Connection
  • LED Monitor
Last response: in Graphics & Displays
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September 16, 2014 10:09:45 AM

Hi everyone,

I have 4 LED TVs connected to 4 PCs experiencing flickering and sometimes total loss of display for a minute or two. Also, at all times, if you look closely you can see parts of the display jittering around. I have been troubleshooting for weeks with no success. Here's the setup:

3 Sharp 42" LED TVs (LC-42LB150U) connected to 3 Dell Optiplex 740 PCs.
Each PC has an AMD Radeon HD 5450 PCI-E video card installed, because onboard graphics didn't cut it. We'll call these DISPLAYPCs #1-3.

1 Samsung 60" LED TV (Series 6 | 6003) connected to an HP Pavilion Slimline s5610y, using onboard graphics. We'll call this DISPLAYPC #4.

All PCs are located in an office about 100ft away from the TVs. Each PC connects to its own TV using VGA baluns which allow me to run video through CAT5. In other words, there's a VGA balun at each TV and PC, and about 100ft of CAT5 between them.

The baluns are made by MCM Electronics (model 50-10250) and according to their specs, should have no problem displaying over 100ft at the current resolutions.


Here are the PC resolutions:

DISPLAYPCs #1-3: 1280x800
DISPLAYPC #4: 1280x720

The TV resolutions are:

DISPLAYPCs #1-3: 1440x900
DISPLAYPC #4: 1360x768

I found that these resolution settings give me the best accuracy in terms of covering the whole TV screen instead of partial area with black bars on the sides. Hopefully I'm not complicating things too much with this info, but I want to give as much detail as possible so that there are no surprises for you guys later on.

The display properties on DISPLAYPCs 1-3 only allow one refresh rate for the TVs: 60Hz
The display properties on DISPLAYPC 4 allow 50, 59, or 60Hz. I just now noticed this one having multiple options, so I haven't gotten around to tinkering with those yet.

Refresh rate is what I'm going to focus on next. I may try a program I read about called Powerstrip to see if that helps, but in the meantime, any insight or help troubleshooting this would be much appreciated!



More about : hdtvs flickering connection

September 16, 2014 11:04:58 AM

Run all those tvs on native resolution.
Make sure all cables are firmly attached.
Reinstall graphics drivers.
If all tvs all flicker then maybe problem with tvs so try it on a monitor.
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September 25, 2014 10:04:28 AM

Setting the resolutions as close as possible to each other from PC to software to TV has eliminated the jittery-ness of images, which is a plus, but I'm still experiencing flickering from time to time. They'll just start tweaking out, the picture going in and out for about 30 seconds, all at the same time. The power to the TV seems to stay on the whole time while this happens.

Connections are firmly attached, new graphics drivers, all good.

This setup is in a restaurant and I'm beginning to think maybe something between the PCs and TVs interferes with the signal. Is that possible? Could this be a power issue with the electrical circuit the TVs or PCs run on? I'm not seeing anything unusual show up in Event Viewer on the PCs about video.

I'm not an electrician but I'd like to be able to tell for sure if this is some kind of power issue, or if it actually is a tech issue. Because so far the disgruntled owner believes I'm responsible, and I'm doing everything I can to fix it, with no success.

Update: I've connected a 450W power supply to one of the first 3 display PCs, instead of the 250W they come with. This time when the screens flickered, the 450W display stayed on the whole time, though it still had a few black lines pop up. Does anyone know if putting the outlets on their own dedicated electrical circuit would stop this from happening, or do I need to buy new PCs with more power built in? I think it would be more cost efficient if we could put the PCs all on their own circuit, but I'd hate to have the owner waste money on that if it doesn't help.

Maybe I'll just buy a higher power PSU and hook that up until one of the TVs runs steady with no lines whatsoever.

Thank you.
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September 25, 2014 10:53:57 AM

One more thing...

Since these displays work 95% of the time, could an uninterruptible power supply hooked up to the PCs make up for the power cutting back every now and then? Or would I need more powerful power supplies for each PC?
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September 26, 2014 12:48:37 AM

Ok so recently i was also using a VGA cable and same thing happened!.
So let me tell you.
VGA is old school cable which has analog signal and it has bad quality. You need a really high end cable aswell. Even if there is a little twist to cable it might not send signal for about 3-5 seconds( happens to me and i guess same is happening to you).
So either use display port , DVi cable , or HDMI. They have digital signal and quality of cable does not matter. Stay Away from VGA!!.

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