MBP only restarts after rest

Question

Folks,
I'm re-posting this here from another thread in the hope that I'll get a better response. It's a compilation of my observations to date.
Situation:
My MBP has begun to refuse to start on first attempt. This AM it started fine. I then shut it down & tried again a few minutes later. Nothing. Would not restart.
I removed the battery/mag-safe & held the power button down for 5 seconds. I also cleared the PRAM. Yesterday I tried holding the power button down while inserting the power cord. It started. Today I could not replicate this. However, after about 10 tries it finally turned on. Battery is fully charged.
Once booted it runs perfectly. Yesterday, just in case, I made an image of both my Mac & BootCamp partitions. No problem.
This has me stumped. Bad power switch? Loose power switch connection? I'm perfectly willing to fix this myself if somebody can point me in the right direction.
Update:
I went to my local Apple Store & spoke with one of their techs. Very professional.
He suggested I replace the upper case. I can do that.
However, after I came home I had a thought (rare enough), so I tried a little experiment. I discovered that, if I leave the machine off for 18 minutes or more, it starts just fine. Every time.
Could this be a temperature/heat related matter? And, if so, what could the heat be affecting??
Update #2:
I haven't heard a word from anyone as to the possible cause of this phenomenon; except to try installing a new $300 upper case.
I'm becoming concerned that I may have no choice but to ship this rig back to Apple. I'd hate to do that. I don't want to be without it for the weeks it would take to maybe find the problem & maybe fix it. I'll fix it myself, if only I can isolate the culprit.
So, here's what I've done since the last entry:
1.) I timed how long it takes for it to "recover" so that it will power up after being shut down. It was between 18 & 20 minutes.
2.) I ran Tech Tool Pro 4. It passed every test, including memory.
3.) CPU temp at rest is somewhere around low 40's to mid 50's Celsius. That's about 5 degrees higher than my new iMac at work, but this is a Core Duo MBP & they tend to run warm.
4.) I ran Software Update last night. It updated and rebooted fine. But, that didn't involve using the power button.
My next test will be to see if it will do a hard shut down immediately after boot; before the unit has had a chance to get hot. But, hopefully someone will have a suggestion in the meantime.
Update #3:
This AM I pressed the power button & started the boot process. I then, after about 15 second pressed & held the button down to see if it would power down. It did.
I then rebooted & allowed it to fully load. Then, after about 2 minutes, I tried a hard shutdown. No go.
Therefore, it would seem that either heat, or some "full" electrical charge (?) is preventing the power button shutdown or startup after it has been allowed to completely boot.
After about 20 minutes, after the heat or charge has dissipated, it works just fine.
If I have to send this machine to Apple so be it. But, my growing concern is that this problem is so obscure that I might be without my computer for a considerable period of time.
At this point any and all comments are more than welcome. I'm desperate.
Thanks,
Jack

Answer 1

S.U. &/or anyone else,
O.K., I'm back to square one.
History:
1.) I discovered that my MBP would only restart after a rest period of somewhere around 20 minutes. I assumed a heat/power button issue. My local Apple Store tech suggested that upper case needed replacement.
2.) On a whim If discovered that if I pressed the TYGH keys fairly hard the machine would restart immediately, without the waiting period mentioned in #1 above. Since the keyboard cable to logic board connector is right under these keys I assumed that the connector was loose. I ordered some Kapton tape and planned to reseat the keyboard connector and retape it more securely.
3.) While waiting for the tape to arrive I kept using the TYGH key combo if I needed a fast resart. But, after 2-3 days of doing this I noticed that it didn't always immediately work; that I would need to repeat the process. Then after the machine booted I noticed that some keys began to refuse to work. If I pressed randomly around the board eventually they would come to life, but not always stay alive. It seemed to be getting worse, so to prevent further damage I retired the MBP & grabbed my old iBook G3.
4.) The tape arrived. Yesterday I opened the case, examine the keyboard cable plug & logic board socket under a magnifier. Both looked undamaged. I then reseated the connector and taped it down securely. Everything looked perfect.
5.) I reassembled the machine, slowly & carefully. I then pushed the power button. Nothing. So, I tried the TYGH combo. The machine started. But, many keys refused to work.
So, here is where it stands. I'm going to assume that I have a keyboard or keyboard cable malfunction; not a power button problem.
Question: I'll get a keyboard from iFixit & install myself if the general consensus is that the keyboard is the problem. But, does the keyboard come with the cable? I see no reason to replace the upper case, since it doesn't come with the keyboard, only the power button & trackpad. and, that doesn't seem to be the problem.
Any further suggestion in this situation are more than welcome.