Why is only 1 of the 3 HDMI connections working. Only port 2 seem to be working. I've switched HDMI cables and the problem persists.

try connecting your blue ray player to HDMI 1.
A) If it works there, then you know the port on the TV is OK & the problem is with either your HDMI cable or your cable box.
B)If it still doesn't work then you may have a problem with the port on your MAIN PCB. if it's a new TV your warranty will cover that as long as the input connector is not physically broken.

have you tried resetting your cable box? you can do this usually by either holding its power button in until all 3 lights light up, or by unplugging it from power , wait @ 30 seconds & plug back in .

It would seem either a setting at the ps3 or the set is not right.

Good idea to check all inputs and setup again--if something like a DVD works on rear input issue is with the PS3.

Make sure you are on right input. On your remote press input until you are on the right one.

Normally you will see this when connecting to a television that only accepts 640X480 resolution. You may be able to increase from that slightly after getting 640X480 working.
When you've made all the cable connections right-click on the desktop, then choose PROPERTIES from the bottom of the list.
A small window will appear with a few tabs on the top choose the last one, SETTINGS.
Click on the screen shown on this tab with a numeral 2 shown. On the middle-left you'll see a slider showing large and smaller at each end, bring it down to 640X480, then hit apply
A pop-up will appear asking you to confirm that this size is working, click yes if when it does.
Try increasing the resolution by a notch to see if the next size up works with your TV. If you see the Invalid Format on your TV again, you've gone higher than this particular input on your TV will accept.
To get a higher resolution signal you made need to switch to a different cable type, try DVI or HDMI. Either of the two should work more automatically than the VGA cable you are now trying.
If your computer only has a DVI port and the TV has an HDMI port you can get a cable that has DVI at one end and HDMI at the other by clicking here:

If it's the first time using your PS3, use the composite cables that came with it. Turn on the PS3 go to video settings and switch the input to HDMI. After you've switched to HDMI, turn the PS3 off and connect your HDMI cable, go back to video settings and change the resolution to 1080p. If this isn't the first time you've used HDMI for your PS3, make sure your T.V. is on the correct input. If the T.V. is on the correct input, try switching the HDMI cable to a different input. If that doesn't work try using a different HDMI cable, testing different HDMI connections if you're still getting the black screen. If none of those work then it's probably a problem with the PS3, but just to make sure try plugging something else with HDMI to see if that works. If another HDMI device works, then it's your PS3, if it doesn't then it could be a problem with your HDMI connections on the T.V.

If you just bought the PS3 use your composite cables that came with the system. Turn the PS3 on and go to the video settings, set up video input to HDMI. After you've done that plug your HDMI back into your PS3 and try turning it on. If that works go back to video settings and change the resolution to 1080p. If that doesn't work make sure your T.V. is on the same input that the HDMI cable is plugged in. If it is and still doesn't work try switching to a different HDMI port. If switching to a different HDMI port doesn't work try a new HDMI cable. If the new HDMI cable doesn't work then there is a problem with the port on the PS3 which would require a repair.

sounds to me like a bad HDMI cable. Just replace it.
If HDMI still wont show, move to another HDMI port. But based on having to hold HDMI cable with hand to steady the connection, it is either a bad HDMI cable, or a bad HDMI port on the receiver. Good luck

My best bet would be a port issue - see if another device will work plugged into that port. (Some HDTVs have a HDMI port strictly for Service and nothing else but a Technicians specified cable will work in this port, look at the Manual) Check to see if your TV is set to the same port as your connecting to. One will be HDMI 1, next HDMI 2 and so on, the input button on remote should switch from port to port, make sure port setting on TV is same as #port your connected to.

when you switch the ps3 on if you hold down the power button for more than 4 seconds it runs the display setup. and sets the ps3 to run in the best possible option