Mini suddenly cuts / switches off

Question

Hi,
I own a Mac Mini (1,42GHz, 1Gig ram) and recently it's done some strange things. While working it suddenly switched off. It was like somebody just cut the power. I pushed the button to turn it on again and the led would only appear for about 1s before the mini cut off again. When waiting for about an hour leaving it switched off it worked again, but only for a few minutes. My first guess was a problem with the overal power (bad contact or something) so I tried the mini in another plug and in another house, but the problems continued. I couldn't run the hardware test since it kept cutting off before it could complete any test.
Then I decided to visit the local Apple store (not a 'real' one as it's a shame they don't exist in Brussels, but a certified reseller). I wanted to ask them if they could try it with a different power supply as that might be the issue. However, since I bought the mini from the online Apple store and not their store they weren't allowed to test it unless I brought it in officially, paid them, would pay them more if they couldn't find anything and they would send it to Apple for repair.
So I decided to call Apple first and they had never heard of the problem. I reset the PMU (?), tried some stuff, but nothing worked. They told me to go through the local store to get it sent to them if the problem persisted. So the next day I wanted to reproduce the problem before going to the store to show them right away and the mini worked for about 5 hours straight. It seems the longer I left it switched off, the longer it work afterwards. When waking up from a sleep it crashed again. Then I thought it wouldn't turn on again like it did all the time the day before. However it ran perfectly for 2 whole days. Since the mini is pretty essential for my studies I gave it another try and decided not to bring it in. I was able to run the hardware test which told me everything's ok.
Right now it works pretty well, but it still suddenly cuts off every once in a while (about once a week). Did anyone ever have this problem before or has a hint on how to prevent this from happening? Would it be better to bring it in for repair anyway? My fear is that they'll leave it on for a week, see that it works perfectly and send it back saying there's nothing wrong with it. In case nobody knows what to do I did think it would be a good idea to post the problem here anyway to make it known.
Greetings and sorry for the long story .
Edward.

Answer 1

Only valid entry in Apple's Error Codes List for -127:
-127 = fsDSIntErr /*non-hardware Internal file system error*/
You have probably seen the -93 (or was it 96) and -122 PMU codes, but 127 is a first for anyone it seems, even Google won't find a -127.
The -93/96 remedies were mostly centred around PMU resets.
The -122's were a little bit more involved. A Googled report lists the local Apple Store saying it would need a logic board replacement. The user was a bit miffed when 5 days later his machine is ready to be picked up and only the battery was replaced. It PMU forced shutdown -122 again after arriving home. He bought a conditioning UPS and plugged his Mac into that and so ended the report. No further information available on if it solved the problem or not.
Add to that users shutting down and running DiskWarrior/TechToolPro checks of the hard drives as all the -12x error codes are file system related. However when I grep'd the headers list of CarbonCore for -93 it is a network bridging error, and -96 is a Serial port not powered error, so I have doubts that the PMU is using the standard Mac error codes list.
Apple's own online support database is mysteriously silent on any PMU forced shutdown entries.
Jan J.