I just chipped a 39001 NTSC V7 (Bios 070, GH022) with a Ubicom chip, programmed with the ICE 091F2. I tried CDR (i didnt have any dvd game at hand by then), and they worked fine, so I decided to close the PS2 and get ready to go...but, something must have shorted somewhere, because the tray ejected once but would not close (the blue led blinked).
I opened the machine again, closed the tray by hand (when it was turned off, error?), checked the cables...everything seemed fine...but, the discs (two CDR ripped games and the mediaplayer) all showed the RSOD. All the disc where IMATION...I thought, what about the brand...then I tried an audio CD branded IMATION (burned in the same computer than the games) and it was read perfectly....I tried a DVD movie, it worked fine...Collin MCRae 3 DVD Backup, RSOD...
But here comes the strangest thing...I discovered that if I put the PS2 upside down, all the games I have in CDR (PS2 & PSX) work fine...!!!
So, even though the unit is brand new (1 week old), I checked the white cog, azimuth, everything. The same situation remained...upside down is ok, even vertical position up to a degree of 70 is ok too, but any other fails...I removed all the cabling, checked fuses, reinstalled cables, changed chip, danced to the gods, changed software in the chip...
Finally I discovered an odd behavior in the laser head...when the PS2 is upside down, and you reset the unit, the red laser (DVD) flashes just a moment (half second or so), and then it switches to infrared to read the CD (this is ok, i think)...but when I put the unit in its normal position, the red light doesn't turn off until the browser menu appears, and after a little while the red laser turns off, and then the RSOD appears...the disc spins everytime (so i thinks this has nothing to do with the rotating motor).
I took one of the chips I tried in this machine, and installed it in another V7 (exact same model), it worked fine with everything I throwed at it.
Is it possible that something can cause the magic chip to force the PS2 to read in DVD mode when a CD is inserted? I don't think so, but... And why doesn't it happen when the PS2 is upside down? Also, backup DVDs don't work at all...My best guess is that the modchip can't find the sync bytes it searches for before applying the patch, the reason for this is unknown to me (perhaps it takes too long to read the CD, or there is some error correction involved because something is underperfoming)
The only thing left to try is swapping the drive with the one from another unit, to determine if the problem is in the mobo or in the laser...
Short of display the Nintendo logo, I don't know a weirdest scenario.
Thanks for any help or suggestion.