I recently bought a Back to the Future and had to replace a few diodes on the power supply board. Now that the diodes are replaced when I turn the game on it seems to reset over and over. Doc says "Back to the Future" and it will reset, then it may make it to the point where things start coming up on the display then it resets again. There is no real pattern for when it resets. Sometimes it will make it further than others.

Any ideas?

Well this is odd. The machine is working fine now. Is there some sort of battery that need to be charged initially? The machine had sat for quite a while before I bought it.