HDMI connection on TV acting up - No Signal on input #3 Mystery

[kach22i]

I have a less than a year old Panasonic Plasma TC-P60ST50.

About a month ago the HDMI connection on my laptop computer to the TV was acting up, I had to angle and tension the cable just right to get it to work, but it worked. Often a wiggle on the computer connection or a reconnect on the computer end solved the issue.

Then a couple of weeks ago I could not get it to work, no matter how much I fussed with it.

I just gave up, decided that I'd give it a rest. I figured the computer HDMI connection just wore out from the roughly four times a week plug in and out routine. However, I always got (and still get) that bleep sound which said it knew I had just put the HDMI cable on or pulled it off.

Last week I got a new HDMI cable, but it's a short 6-footer. I decided to plug it into input #3 on the TV and connect it to my laptop, and it worked.

Then felling lucky, I reconnected my original long HDMI cable back to the TV, and connected it to the computer, and that worked too. I watched several episodes of a TV series off the computer using the TV as a monitor.

I conclude that my problems must have been the connection to the TV.

This morning (the next morning) I hook up my computer to the TV, select the Input for computer #3 HDMI Input, and get the same old "No Signal" TV screen pop up.

I just did a TV software update, and tried swapping HDMI cable again, but to no avail, it's still not working.

I still get that audio confirmation or bleep sound which says I just put it on or pulled it off from the computer (computer makes the sound).

I'm about to order some swivel type HDMI connector jacks which will allow me to access the currently unused Input #1 which is too close to other inputs to be of use right now. However by-passing Input #3 is not really solving the issue - just avoiding it. HDMI Input #2 is my Blu-Ray player and has never given me a problem.

This problem defies by ability to diagnose it, I'm just too close to the problem.

Any ideas on what the solution is?

 

[kach22i]

I just ordered a $25 HDMI cable signal tester, some spare cables, extra elbow connectors and jumpers.

I'll get to the bottom of this sooner or later.

I did try my wife's computer tonight as I did last night (forgot to mention), still nothing.

EDIT: 11/28/2013
The more I think about it, the more I'm convinced that an Windows XP laptop graphics card is not set up to regularly send an HDMI signal down a 50-foot cable. I suspect the receiving end on the TV was overtaxed and that HDMI port got fried as a result.

My new cable will be 16.5 feet long, and snake under the couch (hello kitty-yea my cat chews wires), not though the basement as with the 50-footer I'm now abandoning.

I watched several TV episodes on line last night and also this morning using the previously unused TV HDMI Port-1 with the temporary 6-foot HDMI jumper from TV to laptop computer - no problems.

EDIT 12/04/2013
The 16.5 foot HDMI cable provides an incredible picture, using the original Port-3 on the back of the TV.

I suggest anyone attempting to use a 50-foot HDMI consider using one of those signal repeaters or another method.

My cable tester is on back-order, will find out if the 50-foot cable is bad later on.