Weird picture issues

[kemik]

I have my DM800 in my A/V rack in my cellar of my house connected to a HDMI matrix switch and have a 5m cable running into one lounge and a 10m cable going into another lounge area

Over the 5m cable I have perfect picture no matter whether SD or HD, however on my 10m cable I see shades of green on black part of the screen and shades of pink on white parts of the screen occasionally and its starting to drive me mad. As I'm not use whether its channel related or not or cable related even as I also have my Sky HD box plugged into the matrix switch and if I use that over the 5m or 10m cable the picture is perfect.

Naturally one would suspect the longer cable but I'm not convinced it is the cable and the biggest problem is that I can't easily replace the 10m cable now that the floor has been put down, etc otherwise I would have been able to eliminate that quite quickly.

Any one seen the same or have any suggestions? I've seen inline boosters been mentioned in various threads might they help?

Thanks

[Giga]

try 10m cable with DM800 without the switch and see if that is ok?
are you using 1080i on both boxes or 1080p on DM800 if that is possible? Bandwith for 1080p could be to small? HDMI spec should be 1.3.

[kemik]

Can't really try without the switch as I don't have a way of connecting the 10m HDMI cable to the DVI-HDMI DM cable :-( but don't think its the matrix switch as the Sly HD box also goes through same cable and uses the switch and thats fine

Its set as 720p as the DM800 only supports up to 1080i. Therefore due to the better picture with progressive scan as opposed interlace I choose to run 720p

[Giga]

Might be the combination, just going over the limit? DVI-HDMI DM + HDMI matrix switch + 10m HDMI cable?Can you borrow somewhere a HDMI Coupler / HDMI Joiner 1.3? and see if that works?
http://www.tvcables.co.uk/images/items/hdmi-coupler.jpg

[kemik]

but surely that would also screw up my Sly HD box too which is my point I think the cable is a red herring possibly

[kebien]

Not sure what you want the response to be.
The fact that you have to troubleshoot to find what is wrong,involve you changing some stuff,either by buying them or ask a friend for other cable,or move the dm800 closer,or whatever is.
There is no way someone can give you the exact solution for your problem.
So,this are the options,all involve you expending some money on gadgets:
Get a new and better 10 m cable,most probably the cause of your problem.
The dm800 might be delivering lower signal in HDMI than your skybox.

next option involve you to test each item in the link using some equipment you might have handy.

[kemik]

Well one of the things I was really trying to ascertain whether anyone else had ever seen the pink on white or green on black issues and if they had what did they find caused the issue

[Giga]

those would indicate a signal break up:
you have to find out by excluding possible cause.
DM800: find another DVI source: friends, ...
dvi to hdmi cable: find another one: friends, ...
switch (find another one or leave it out)
...