Purple picture - hdmi lead fault?

[startingout]

I'm coming to the end putting a small cinema room together with a Benq 7700 pj, Denon 3806 amp, 1920 dvd and kef 2002.2 speakers. Just the screen to make and it should be finished. However being unable to wait I've been watching on an emulsioned wall and been very happy with the result. Recently though the picture has turned purple - not a purple tint but really purple. This has been an intermittant problem as often it goes back to normal. All connections are ok and have tried a new lead between projector and amp(hdmi). This seems to have cured the problem but I can't be sure as it's so intermittent. I really hope that the lead isn't the problem as it's chased into a concrete floor, plastered walls, under carpets upstairs etc. etc. The replacement is looped across the room! Has anyone experienced this kind of problem or have any ideas on what I can do to work out exactly whats wrong?
Cheers.

[bsuttie]

I'm afraid it does sound like a cable problem as HDMI carries red green and blue separately. It sounds like there's a problem with one of the green signal wires.

Check the cable carefully wherever you do have access, may be something as simple as a carpet staple partially through the cable causing an intermittent short (speaking from experience here).

If that's not it, try wiggling the ends with the projector on and see if you can get the signal back, breaks are frequently near the plugs.

If it is a break you may get away with putting a new end on the cable if you're happy with a soldering iron (and a magnifying glass!)

regards

Brian

[neilneil]

I thought HDMI was a digital signal. Why does it need to separate into components?


-Neil

[bsuttie]

It is a digital signal but because of the very high data rates involved it uses four balanced pairs, for RGB and clock (or option of YCbCr and clock)

I suspect that trying to put everything down one wire (or pair of wires) isn't practical at the data rates and frequencies involved.

regards

Brian

[startingout]

Thanks for this. I was really careful not to have any 90 degree bends etc when routing the cable so it seems more likely that any breaks are at the connectors. Is it really feasible to attack these with a soldering iron, and if so do you know if you can buy new connectors to fit hdmi cable??

Sorry its taken a while to respond but I don't get to log on very often. Thanks again,

Jeremy