when you put q3 back on make sure its not shorting to the back plate check it with a multi meter , and test q3 make sure its not faulty , check for crackes solder on the header pins and the connectors, check the reset board that will give you problems just unplug it , check the 12v br too , and last of all you have to do the ground mods for all the boards adding new grounding wires to all boards ,and do the ground mod on the connector between the driver board and mpu board adding a extra ground wire on that connector, once you iron out these problems your machine will work like gold .

sounds like your back in business good luck