PS2 screen not coming on.

[koalabear1]

I have a PAL PS2 with a NEO4 installed. It was working brilliantly for 3 months and has all of a sudden died. When I connect the PS2 to my TV I get no image on the screen. I have tried two different TV -->PS2 cables but no luck. I originally had a damaged on/off reset cable but replaced that with a brand new one yesterday. I have gone over the wiring of the modchip with a magnifying glass and no wires etc have come loose. I know that the wiring is correct because it was working fine for three months.
I have been very careful not to squash any wires while Im putting the PS2 together. Both the LEDs on the switch work and the disc tray ejects when selected. Is there anything I can try? Is there a fuse on the power supply board that may of blown. I tested the main 240V fuse and thats ok. Any ideas would be very much appreciated.