I have come accross a very weird problem. I initially attempted to install a modbo 745 on a V9 PS2. The PS2 would boot fine and I could enable/disable the chip but the DVD drive would not spin or read anything (I did the ROmeo fix). So I removed the chip and it worked fine so I though it was the chip.
I placed a Matrix Infinity and again it would boot fine, I could enable/disable and I could even access the Matrix settings and change stuff. But when I booted to the PS2 dash ther controller would no longer respond and it would not read disks. Also with the Matrix chip installed I would get no sound at all from the PS2 during boot up. When I remove the chip the PS2 worked fine.
I then tried a DuoGT, it would act the same as the Modbo.
So I redid the wiring and the same problem. So I said forget it and closed it back up..