Dreamcast repair video seems a bit iffy

http://www.youtube.com/watch?feature=endscreen&NR=1&v=Bxuf9BnUxjE

This guy talks for 40 minutes about dreamcast repair and makes some good points
However, at 37 minutes or so he says that the capacitance is fine as long as it's equal to or more than the capacitance of the original but the voltage has to be spot on, I was always taught that the capacitance had to be the same and the voltage could be equal to or higher than.

So what would be the effects of using a capacitor with a capacitance which is too high?

 

Depends on the circuit. Voltage can be equal or greater but capacitance has to be spot on for most things. For video it won't destroy anything but it will produce a picture that may not be desirable.

 

Since the impedance of a capacitor is 1/(i \omega C), I guess C would be important for analogous stuff working at a fixed frequency or if used in a filter. However if it's used as a charge holding device, the voltage applied should be sufficient to deliver the right current for a long enough time.

 

Voltage is the max the cap can accept, it can be higher without issue. The voltage in the circuit will be the same, so the voltage the cap is getting is the same, regardless if you put in a higher rated one.

Capacitance should be the same value. The video is incorrect if it says different

 

Yeah that's exactly what I thought, so that guy is using a 330uf cap to replace the great big 47uf cap on the dreamcast power supply board, I can't imagine that would be a good idea

 

This is why you dont trust everything on the internet and is why I get anal about technical points being accurate. Someone can say something here thats incorrect, then next thing you know theres a youtube video and everyones doing it wrong.