Hi there. I thought I would post this hoping that perhaps soeone has had the problem before and came up with a solution. Here goes. My Moto cable box has a DVI connection which I run to my Panny Plasma via a cable that has an HDMI connection on the other end. Basically a DVI to HDMI conversion cable. This setup has worked flawlessly for about 8 months now. I switched to the DVI connection and found that the picture is superior to the component connection, particularly on SD channels.

Ok, my problem started about 6 weeks ago. When switching from an HD channel to an SD channel, the color goes wacky and the picture goes purple and bright green. I'm thinking that it is some sort of handshake issue that does not go well. When I turn everything off and back on, the picture goes back to normal. Also if I switch back to an HD channel, the picture goes back to normal.

The cable tech has been out and switched cable boxes which did not fix the problem. They are recomending an HDMI equipped cable box that costs $10 more a month which I find unacceptable.

Are there any suggestions or experiences that you guys have that I might employ before I buy a new cable to see if that is the issue ?

Thanks

I think a new cable is a waste of money.

I think a new cable is a waste of money.

So you think the issue is with the cable box ? If that's that case I'm wondering why the heck it just started doing this out of the blue. Any ideas other that what I've mentioned ?

it's possible that they pushed new firmware out to the cable box that is causing it to not play nice anymore...

I'd bet it's something like that too. The cable is passing the signal. It's the two devices that are acting up when you switch resolutions. I hate HDMI/HDCP. My gripes are well documented. Perhaps I'd be okay with the physical cable if stuff actually worked all the time.

it's possible that they pushed new firmware out to the cable box that is causing it to not play nice anymore...

Exactly what I said to the cable tech and he agreed that it very well may be the case. If that's the case, the relacement box with DVI must have been on the same FW release snce it did the same thing.

CSR just called to inform me that I am on his special attention pile (then he changed and said LIST). He thinks it may take a month to get an HDMI box to me that does not have the DVR function that costs an extra $10/mo.

EGAD Charlie Brown ! I just want the fraganackle thing to WORK !!

I'd try looking at another angle here. This sounds like a colorspace problem, and I recall somebody writing to me with just the same problem once upon a time--I do not recall whether he managed to resolve it.

HDMI supports Y/Pb/Pr or RGB colorspace (yes, there's also xvYCC, but that's not likely to be involved here). DVI generally supports only RGB (though the DVI standard is strangely implemented sometimes, so who knows?). If you get colorspaces mixed up, so that a Y/Pb/Pr signal is being interpreted as RGB, it makes for a very green picture with some other funky coloration. It could be that your cable box and your display are, for some reason, getting mixed up on colorspace. The other person who asked me about this very problem had the same situation: it shifted when moving from a high-def to a standard-def channel.

Look in your device menus, particularly on the cable box but also on the TV. Can you select the colorspace settings? If so, try setting everything to RGB on both ends. My suspicion would be that something wacky like this is going on: when the box receives a digital channel, it gets colorspace instruction from the underlying signal, and renders the picture correctly, but when it goes to its own analog tuner and has to create a digital signal from an analog source, its own internal circuit generates a Y/Pb/Pr signal (yeah, DVI's not supposed to do that, but I'm guessing here that something isn't wholly kosher). Your TV very likely realizes it's getting a DVI signal in, and assumes the colorspace will always be RGB, and so it takes that Y/Pb/Pr and renders it as though it were RGB, making the weird picture you see.

Anyhow: it could of course be something else entirely, but it sure sounds like colorspace to me, and I'd look at that before looking for anything else as the cause. Good luck--I know how frustrating these things can be!

Kurt
Blue Jeans Cable (http://www.bluejeanscable.com/store/hdmi-cables/index.htm)

P.S. -- Going back to the last question in your first message: it's very hard to imagine how this could be caused by the cable unless there's something wrong such as very high capacitance on the DDC channel, and that's likely only if the cable is quite long (i.e., at least 30 feet, probably longer).

thanks for that kurt... i never even thought about a colorspace conflict... :o

I think it's a weird handshake problem, perhaps causing confusion at the display with regards to colorspace as Kurt mentions.

How is your cable box setup, it sounds like this only happens when you move between HD and SD channels, is the output resolution for SD channels set differently than HD such that the TV has to re-sync to a new resolution every time?

Instead, try putting the cable box in stretch mode for SD channels, so everything is output at the same HD resolution (1080i probably?) and this should keep the signals coming out of the cable box at the same 1080i all the time, thus no re-syncing every time you move between SD/HD channels.

This is a simple, and free solution. ;)

There was a recent firmware update to several CATV suppliers (Firmware is from Mystro) that has created a number of issues when going between HD-SD.
In the past with most firmware (ex: Aptiva or Pace-Pioneer) you could set the STB to a single rez output, with the Mystro firmware the STB wants to default to the native rez of the channel (typically 480i). Many displays do not like to see 480i on HDMI and this will cause conflicts (and DDC timeouts).
The Moto box in general are known to be an issue, particularly whem it comes to the DDC feeds.
The first thing that I would try is to set the STB to a single fixed (native to the display) rez, this should resolve your problem.