| Author |
Message |
Elaine Benes
Joined: 25 Apr 2006
Posts: 1416
|
| Posted: Tue Sep 09, 2008 6:14 pm Post subject: |
|
|
| Satanier wrote: |
Do you see the greyscale pattern at the bottom of the test image I posted? What are those vertical lines on the left side of the squares? Thats the vertical white line issue I was talking about. |
I can only guess...sorry...looks like cable reflection perhaps, or video noise from some other source... Are you using a 75ohm cable from your source, or a 50ohm one ? Often, the VGA to 5BNC cables you get from ebay are 50ohm, not 75ohm. I'm not sure if that would even cause that though... I've seen similar noise when using an Extron interface...
I'm just guessing its video noise though...
|
|
| Back to top |
|
 |
Elaine Benes
Joined: 25 Apr 2006
Posts: 1416
|
| Posted: Tue Sep 09, 2008 6:15 pm Post subject: |
|
|
| dropzone7 wrote: | | Holy crap! You guys pulled an all-nighter with this I see. |
Huh ? Last day of my vacation, I was in bed a bit earlier than normal actually...
|
|
| Back to top |
|
|
dropzone7
Joined: 12 Jun 2007
Posts: 1069
Location: Charlotte, NC
|
| Posted: Tue Sep 09, 2008 6:17 pm Post subject: |
|
|
Geez...good to know! 24hr. chat support. 
_________________
"Coffee is for Closers."
|
|
| Back to top |
|
|
Satanier
Joined: 25 Aug 2008
Posts: 185
|
| Posted: Tue Sep 09, 2008 6:22 pm Post subject: |
|
|
| dropzone7 wrote: | | Geez...good to know! 24hr. chat support. |
He helped me through the whole process, right when I had given up all hope he saved me! Very nice guy.
|
|
| Back to top |
|
|
dropzone7
Joined: 12 Jun 2007
Posts: 1069
Location: Charlotte, NC
|
| Posted: Tue Sep 09, 2008 6:24 pm Post subject: |
|
|
| Satanier wrote: | | dropzone7 wrote: | | Geez...good to know! 24hr. chat support. |
He helped me through the whole process, right when I had given up all hope he saved me! Very nice guy. |
Yeah, he helped me a lot as well but you must be a much faster study than me because you got most of it done in one night! I would gladly trade my nights of headaches and frustration for your one night of "convergence nightmares"! 
_________________
"Coffee is for Closers."
|
|
| Back to top |
|
|
Satanier
Joined: 25 Aug 2008
Posts: 185
|
| Posted: Tue Sep 09, 2008 6:24 pm Post subject: |
|
|
| Elaine Benes wrote: | | Satanier wrote: |
Do you see the greyscale pattern at the bottom of the test image I posted? What are those vertical lines on the left side of the squares? Thats the vertical white line issue I was talking about. |
I can only guess...sorry...looks like cable reflection perhaps, or video noise from some other source... Are you using a 75ohm cable from your source, or a 50ohm one ? Often, the VGA to 5BNC cables you get from ebay are 50ohm, not 75ohm. I'm not sure if that would even cause that though... I've seen similar noise when using an Extron interface...
I'm just guessing its video noise though... |
http://www.monoprice.com/products/product.asp?c_id=102&cp_id=10203&cs_id=1020304&p_id=567&seq=1&format=2#description
^^^^^ That's the cable I'm using, but I have two pretty thin VGA extenders on it to get to my computer in the other room.
When I get a chance I'll look into it. I just hope nothings broken inside the PJ, I also see the lines on the far left side and somewhat on the right during all white field. I don't notice it in movies so if it's not hurting anything I don't really mind.
|
|
| Back to top |
|
|
dropzone7
Joined: 12 Jun 2007
Posts: 1069
Location: Charlotte, NC
|
| Posted: Tue Sep 09, 2008 6:39 pm Post subject: |
|
|
Although I'm not currently using it, I have used that exact same cable before with no issues. I would say it's more likely to be the VGA extenders or something to do with your HTPC. Try taking the computer in the same room as the projector and take the extenders out of the chain.
_________________
"Coffee is for Closers."
|
|
| Back to top |
|
|
Elaine Benes
Joined: 25 Apr 2006
Posts: 1416
|
| Posted: Tue Sep 09, 2008 6:42 pm Post subject: |
|
|
Your video chain is only as good as the weakest link. You can have a $10,000. cable, but if you connect it to a $.10 "extender" from Rat Shack, THAT is the part which determines the quality of your video chain...
That breakout cable from Monoprice is "ok" quality wise, but its got 50ohm computer BNC's on it instead of the 75ohm connectors you want for this application.
Personally, I wouldn't worry too too much about it, I'd bet its caused by the cables...
IMHO, there doesn't appear to be anything at all wrong with the operation of your newly acquired projector, relax and enjoy it...
|
|
| Back to top |
|
|
kschmit2
Joined: 09 Mar 2006
Posts: 1141
Location: Heidelberg, Germany
|
| Posted: Wed Sep 10, 2008 7:17 am Post subject: |
|
|
the faint white lines on the left should be raster ringing. Try to increase the back porches.
Standard BNC connectors (those with a dielectric) are always 50 Ohm. They are intended for RF applications (2 to 4 GHz), and thus an impedence mismatch will have virtually no effect in video applications with their relatively low frequencies.
Your PJ should have 50 Ohm connectors (like pretty much any CRT or digital PJ).
What you have to make sure though is that your cables are actually 75 Ohm coax.
|
|
| Back to top |
|
|
Satanier
Joined: 25 Aug 2008
Posts: 185
|
| Posted: Wed Sep 10, 2008 7:18 pm Post subject: |
|
|
| kschmit2 wrote: | the faint white lines on the left should be raster ringing. Try to increase the back porches.
Standard BNC connectors (those with a dielectric) are always 50 Ohm. They are intended for RF applications (2 to 4 GHz), and thus an impedence mismatch will have virtually no effect in video applications with their relatively low frequencies.
Your PJ should have 50 Ohm connectors (like pretty much any CRT or digital PJ).
What you have to make sure though is that your cables are actually 75 Ohm coax. |
Raster ringing... hmm Well I'm using a standard 1920x1080 resoltion from the windows desktop properties, using dual monitors, sending that resoltion to the projector. I guess I would have to create a custom resolution in my nvidia control panel to adjust the porches, and I was having lots of problems with that. I would also have to redo my setup if I changed resolutions, correct? Is there any risk just leaving it as is if its not bothering me in movies?
|
|
| Back to top |
|
|
Elaine Benes
Joined: 25 Apr 2006
Posts: 1416
|
| Posted: Thu Sep 11, 2008 12:25 am Post subject: |
|
|
No, nothing wrong with leaving it alone if it doesn't bother you...
Getting rid of those two vga extenders will likely clear them up though...
|
|
| Back to top |
|
|
|
|
