connecting HP 2311x display to new macbook pro Retina - no output on external screen
I have a brand new MacBook Pro 15 in. with Retina display. I also have a HP 2311x monitor. When I plug in the HDMI cable, the external monitor says "check video cable" and the preferences "arrangement" thinks there is a display - even recognizes the type - but the external display just wont display anything but the "check video cable" box. I spent 2 hours on with apple yesterday, they had me do all sorts of resets and stuff - but no luck. The HDMi cable works when connecting a pc to the screen. When connected to by macbook, the screen on the macbook likes to flash black and its annoying. I have gotten really used to working with two screens.... and apple's suggestion was to buy a thunderbolt cable and try that. As it is, with this new macbook I have to buy a bunch of cables, I really don't want to buy another one when I am not sure that will work. Darn things are expensive when you are buying 4 connectors at once (ethernet connector since the speed via wireless is noticably slower; magsafe to magsafe2 converter; thunderbolt for my printer; and a connector for the monitor at home which doesn't have an hdmi port).
Any other suggestions before adding another to that list? Since Apple seems to be out of ideas... any info would be appreciated.
MacBook Pro with Retina display, iOS 7.0.3