I installed a DMS3 on my V.7 PS2. The PS2 would load but it wouldn't read backup or original games. I went back and resoldered wires R-W and at the same time I had to resolder Q because I accidentily pulled it off (not really pulled). I reconnected all the cables and reassembled as much of my PS2 as I need to start it up.
After I powered my PS2 back up, no screen would come on. The power button would turn on and off but there was no light for the DVD tray. Does anyone know which point would effect this?