SA8300HD flickering picture with HDMI cables but not component cables??

Hello all....

Thanks in advance for any help.

My system is the following: Scientific Atlantic 8300 HD Cable Box, Panasonic TH-50PHD8UK monitor, a Sony HD DVD player, and a Yamaha RX-V2600 receiver.

Until very recently I was using good component cables for all connections and never had any problems.

But I switched to HDMI cables for all connections and now Im having a big problem watching both HD and non HD tv channels. I should note that I dont seem to be having any picture problems when watching a DVD.

For some reason, when I turn on my SA 8300 HD cable box, the HD channels are totally black, no picture or no sound, for about a half hour!!?? Finally after some time, like a half hour, finally I get a picture???

So while Im waiting for the HD channels to come in, I of course watch the non HD channels but there are numerous lines across the screen and the picture randomly flashes on and off. Basically a very bad picture.

I called Comcast, and they said they dont really support HDMI cables and told me to switch back to component cables. I can do that but there must be something wrong here right??? Ive tried to find other posts that address this problem but none seemed thatr similar.

After the half hour, I can finally watch the HD channels but they often flicker in and out - even when Im just using the menu guide or something.

Any ideas??? Please help!!

HDMI is an evolving standard and you often hear stories of problems.My own set will accept video from HD-DVD player over HDMI but will not accept video from my Bluray player or cable box.Component seems to be more stable and always seem to work. I wonder if the fact that my tv is a Toshiba has anything to do with it only accepting signal from a Toshiba player.

bill

make sure the components are out of sa box while using hdmi.
also on remote press red menu button twice and make sure settings to hdmi and the setting is to auto format out then exit and turn off box hold down guide and info buttons on front of box and follow advanced set up.you only want to pick outputs your tv can handle 1080i 720 try not to use the 2 480p's in middle 2 on bottom are best usually.
also it sounds like your picture is tiling do you get little blocks across screen?if so you have a problem with the higher freq.coming thru coax make sure the conx,cable and splits are good not going thru a vcr or power strip first if uncomfortable with hook ups you will need someone out there for service.