# ASK DBSTalk: 921 losing sync with tv



## steveo (Jan 31, 2004)

I just turned on my 921. I had a model 6000 connected to philips 46pp9302 with a vga/rgb cable. I am using the same cable with a DVI-A-M to VGA HDDB15-F adapter. The picture is fine when the 921 is outputing 480p but when I switch to 1080i the TV loses sync, I get picture roll and or distorted images. The TV status indicates 1080i format. The TV also has a composite, Y Pr Pb, input that works fine in either 480p or 1080i. The model 6000 setup worked fine, any ideas on what is different with the 921 setup?


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## Mark Lamutt (Mar 24, 2002)

steveo - I'm not clear what your connection is from your post, probably because I'm not familiar with your conversion. What's DVI-A-M? Are there settings on your converter that can be tweaked? The 921 DVI port puts out a digital signal if it detects a digital device connected, and it puts out an analog signal if an analog device is connected. IE when I connected a VGA monitor to my 921 with a DVI to VGA dongle converter, I was viewing an analog signal out through the DVI port. 

Bottom line is I suspect your converter is not liking the DVI output of the 921.


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## steveo (Jan 31, 2004)

Mark, I'm sorrry. The DVI-A-M to VGA HDDB15-F adapter is just a hardware adapter to connect the analog signal on the DVI connector to a 15 pin VGA connector, sounds similar to your dongle. I have the adapter on the back of the 921 and the VGA cable connected to it. Again it is a hardwire connection that works for 480p but not 1080i. Both modes work when connected tothe 6000.

Here is a link to a similar product.
http://www.pccables.com/cgi-bin/ord...no=00676&search=DVI&rsite=pccables.com&rcode=

The manual for my TV shows the following VGA input definition:
G/Y: 1.0Vp-p, 75 ohms (compatible with sync on green)
R/Pr: 700 mVp-p, 75 ohms
B/Pb: 700 mVp-p, 75 ohms
H: 3 Vp-p +-1.0V, 1Kohm (when using seperate H and V sync)
V: 3 Vp-p +-1.0V, 1Kohm (when using seperate H and V sync)
Thanks.


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## Mark Lamutt (Mar 24, 2002)

Yeah, that looks similar to what I tested with. Obviously your television doesn't like the signal that's coming out of the connector. I don't know enough about it to give you a good reason why, though.


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## kmcnamara (Jan 30, 2004)

It sounds like you're connecting your 921 like I am. I am using a DVI-A adapter to connect my 921 to a VGA/RGB cable. I also got the picture roll you're talking about when I first turned on my 921. But after about 30 seconds, it synced and has been fine ever since.

Are the blue and orange (HD and SD) lights both on? If so, press the HD button on the remote to switch to HD only mode. See if that helps.


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## steveo (Jan 31, 2004)

kmcnamara said:


> It sounds like you're connecting your 921 like I am. I am using a DVI-A adapter to connect my 921 to a VGA/RGB cable. I also got the picture roll you're talking about when I first turned on my 921. But after about 30 seconds, it synced and has been fine ever since.
> 
> Are the blue and orange (HD and SD) lights both on? If so, press the HD button on the remote to switch to HD only mode. See if that helps.


It looks like my problem is horizontal & vertical sync, or lack there of. On some video content the picture is discernable, you can tell what is there. But with other video content the picture is totally messed up. I'm not sure if the signal levels are different on the 921 vs. the 6000? I would like to use my Y Pb Pr inputs for my progressive scan DVD player and use the RGB input for the 921.


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## kmcnamara (Jan 30, 2004)

By the way, that adapter you're using has the same exact pin-outs that mine has. Weird that you're having the problem.


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## steveo (Jan 31, 2004)

kmcnamara said:


> By the way, that adapter you're using has the same exact pin-outs that mine has. Weird that you're having the problem.


I did try connecting a 17" Samsung computer monitor to the 921 using the same DVI to VGA adapter and it works fine. The monitor has a pendant VGA cable.
Two things come to mind:
First, are the sync signal levels different on the 921 and 6000?

Second are there better quality VGA vables that I can try to connect up to my tv? 
Thanks for any suggestions.


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## wcswett (Jan 7, 2003)

Mark Lamutt said:


> The 921 DVI port puts out a digital signal if it detects a digital device connected, and it puts out an analog signal if an analog device is connected.


Mark, will the 921 put out both a Y Pb Pr and a DVI signal at the same time? I hooked mine up with both cables and I get a Y Pb Pr signal for about a second, then that goes away and I get DVI. I'm wondering if the 921 detects the digital connection and turns off the analog.

--- WCS


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## steveo (Jan 31, 2004)

wcswett said:


> Mark, will the 921 put out both a Y Pb Pr and a DVI signal at the same time? I hooked mine up with both cables and I get a Y Pb Pr signal for about a second, then that goes away and I get DVI. I'm wondering if the 921 detects the digital connection and turns off the analog.
> 
> --- WCS


 am only using the analog portion of the DVI when using the DVI to VGA adapter. I do get both Y Pb Pr and DVI analog signals at the same time. My tv set does not lock, sync, on the VGA signal. It did when connected to the 6000.
Thanks


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## Mark Lamutt (Mar 24, 2002)

wcswett - The 921 will output DVI analog and component at the same time, but if it detects a digital DVI connection, the component video gets shut off and only the digital DVI is output.

Steveo, it's very possible your dongle converter is not converting the DVI analog signal to an RGB signal that your television recognizes. I may be very wrong here (and if so, I'm sure I will be corrected) but I don't think that a DVI analog signal is the same as an RGB analog signal. There was no coversion involved when you were using your 6000. There is now a conversion involved with the 921. DVI analog converted to RGB worked for me when I connected a VGA monitor, but monitors are much more flexible with input frequencies than televisions are.


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## kmcnamara (Jan 30, 2004)

Mark Lamutt said:


> Steveo, it's very possible your dongle converter is not converting the DVI analog signal to an RGB signal that your television recognizes. I may be very wrong here (and if so, I'm sure I will be corrected) but I don't think that a DVI analog signal is the same as an RGB analog signal. There was no coversion involved when you were using your 6000. There is now a conversion involved with the 921. DVI analog converted to RGB worked for me when I connected a VGA monitor, but monitors are much more flexible with input frequencies than televisions are.


My 921 is connected to a Sony 1272 CRT front projector via RGB (using the same adapter Steveo is using). My projector can handle just about any frequency thrown at it which is perhaps why it works (even though it took several seconds to sync up the first time I turned on the 921). This seems to indicate that there is something slightly different about the way the 921 RGB outputs vs. the 6000.


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## steveo (Jan 31, 2004)

kmcnamara said:


> My 921 is connected to a Sony 1272 CRT front projector via RGB (using the same adapter Steveo is using). My projector can handle just about any frequency thrown at it which is perhaps why it works (even though it took several seconds to sync up the first time I turned on the 921). This seems to indicate that there is something slightly different about the way the 921 RGB outputs vs. the 6000.


I have the DVI to VGA adapter on the back of the 921 and I am using a inexpensive (~10') VGA 15 pin male to 15 pin male cable. This is the same cable I used with the 6000. I would invest in a more expensive VGA or DVI cable and new adapter if I thought it would help. I am not sure if the analog signal levels of the RGB on the VGA and DVI are the same, or if the horizontal and verticle sync have the same level and or drive capability.


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## steveo (Jan 31, 2004)

As I previously stated, the TV will kind of lock on a picture using the DVI/VGA adapter depending upon video content. I recorded the Zenith test patern off of HDNet and did some testing. When using the color bar picture the tv will lock on most of the picture, on the botom of the screen there is some text etc., and the picture "tears" in that area. This is using a inexpensive 10' VGA cable. I replaced it with an expensive shielded 15' VGA cable and used the same test pattern and the TV would not lock on the picture at all. I have to believe it has to do with the Horizontal/Vertical Sync signal coming from the 921. It is either marginal in signal level or has limited drive capability. It maybe that my Philips TV requires a higher level than others? As stated before, the Philips TV worked fine with model 6000 using the same inexpensive 10' VGA cable. I may try to find a 3-4' cable to try.
Still looking for advice.


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## paulcdavis (Jan 22, 2004)

I have a sync problem with the component outputs of the 921 connected to a Hitachi 32 UDX 10sa 4:3 HDTV. 480p displays fine, but if I switch to 1080i it will periodically lose Horizontal sync and the picture becomes scrambled for awhile until it syncs again.
I thought it was my TV since I don't have another source of 1080i signals to test with, but now I'm not so sure. Maybe there is a problem with the 921 Horizontal sync and some monitors.

Steveo: Will your Phillips sync at 1080i using the component connections?


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## steveo (Jan 31, 2004)

paulcdavis said:


> I have a sync problem with the component outputs of the 921 connected to a Hitachi 32 UDX 10sa 4:3 HDTV. 480p displays fine, but if I switch to 1080i it will periodically lose Horizontal sync and the picture becomes scrambled for awhile until it syncs again.
> I thought it was my TV since I don't have another source of 1080i signals to test with, but now I'm not so sure. Maybe there is a problem with the 921 Horizontal sync and some monitors.
> 
> Steveo: Will your Phillips sync at 1080i using the component connections?


My Philips TV will sync fine with the Y Pb Pr inputs, and it will sync with the 921 DVI output set to 480p, but when it is switched to 1080i it loses sync. As stated earlier the same TV and VGA cable worked fine with the 6000.


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## wcswett (Jan 7, 2003)

Mark Lamutt said:


> wcswett - The 921 will output DVI analog and component at the same time, but if it detects a digital DVI connection, the component video gets shut off and only the digital DVI is output.


Thanks! My television is digital DVI, so that explains that nuisance. 

--- WCS


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