MacBook A1342 wont start, no chimes.

I had to replace the keyboard on my A1342 because it stopped working. I took the Unibody apart and replaced the keyboard (not happy that the keyboard ribbon is far enough into the connector - any tips on locating it securely would be appreciated.) Now it wont start. There is power to the logic board, Magsafe glows green, ( and orange when charging), HDD spins as does the fan, and there is output at the USB slot. I tested the power at the two power pads, The left hand pad reads 0, the right reads 3.37 V. I have seen on here that 3.4V is required to start the machine. Could this be my problem and if so how do I correct it. I am using the correct power charger for the machine (60W).

I have also tried shorting the power pads without the keyboard ribbon in place and it still doesnt turn on.

This is turning into a bit of a project for me and any assistance would be much appreciated. I am relatively new to electronics at this level but am enjoying the learning journey.

Many Thanks