PS3 got a brick but nothing seems to help

Hello,

some background - i already downgraded about 10 ps3's and everything went fine until this time... the problematic ps3 is a slim ps3(JTP-001 board) that came with 3.50 from the factory. i started the NOR dump and everything went fine... i checked the dump and everything seems ok(after all the checks in HxD. i have also done two more dumps just in case ill need them). then i installed the downgrade patch and again, everything went fine but when i reassembled the ps3 with the HDD in it the ps3 didnt turned on... i press the power button and then all i get is just one beep, red light turns into green(so far so good), but 3-5 seconds later the ps3 just cuts his own power off with no beeps no red light no nothing... then i press the power button again and i hear one beep and the red lights returns and i can turn the ps3 on again for few more seconds :(
i know its not the power supply(checked with a working one... no luck). i saw some posts about soldering the TRISTATE point to the SBE on the E3 flat cable still no luck... i tried soldering the tristate to a 3.3v on the board(i can post some pics if it may help) but always the same resault...

does anyone have any clue what i might do wrong?! is there any chance that this issue is hardware related??
any ideas on what can i do to keep the ps3 running long enough for me to rewrite the original dump so i can see if the ps3 is still among us?? :)

any help would be much appreciated!!

thanks again!!
Hzur.