Hoping there is a Newbie Answer for this, Mac Expert Needed!!!

Lo Ladies and Gents, first time posting as I am a PC boy. Well a subzero PC overclocker tbh . Anyway I have been given an old Mac G4 533mhz 256mb of ram. Now this thing has some issues and I am at a stand still with it tbh.
I have check lots of stuff, as follows.
1. Checked the ram I installed, I know alittle about ram and know this is not the problem. added another 512mb.
2, Changed the CDRW to a DVDRW, tested with both and tested with nothing installed on the second IDE channel.
3, Removed the CPU and checked for overclocking or anything else.
4, Removed and serviced the PSU, all rails working well.
5, Checked the battery and reset the Pram etc.
6, Checked the inside of the case, fan operation, condition of the cables.
7, Replaced IDE leads etc.

Thats the back ground done, now onto the problem . After loads of testing, I feel I should have posted for help before. This is very weird and i cannot find a solution to the problem, I hope it is a newbie mistake. I have installed OS9, OSX 10.3.2 and OSX 10.4 Tiger, al the same.

The problem is that when I have the case open the system works like a dream, as I type now I am running on my Mac with the side down. If I put the side up the system starts to crash constantly. if I put it up now say within 5minutes it will crash, it will panic or lock. Now coming from a frozen PC CPU back ground, I would say a heat problem. On testing for this I found the system was hotter open than closed. I also checked the GFX and it's very hot with the side down and cooler with the side up. tbh I would expect this to be the case.
So my question whats wrong with the system, I can only guess that maybe the pressure from the PSU's connector when closed is causing a problem. maybe a dry joint on the mainboard.
Anyway please help, however small please post it

Cheers

Look carefully with a magnifying glass at the traces on the MB. Could be loose solder joint on a chip, component, etc, or a hairline crack. Most likely a lose or cracked solder joint. Cracks can be particularly difficult to find. Failing to find anything visually, you may want to use a reflow tip (hot air) if you have one, over some areas that may be receiving stress when you close the door.

ed724

ed724 said:

Look carefully with a magnifying glass at the traces on the MB. Could be loose solder joint on a chip, component, etc, or a hairline crack. Most likely a lose or cracked solder joint. Cracks can be particulary difficult to find. Failing to find anything visually, you may want to use a reflow tip (hot air) if you have one, over some areas that may be receiving stress when you close the door.

ed724

Click to expand...

Yes i very much feel this is the only option left
Thankyou for your reply, helps to confirm my thoughts.

Cheers