Okay, this setup is makeshift so that might just be the problem. Right now I have the picopsu wired to the dreamcast but whenever I plug it in, the dreamcast's light flickers and at the same time I see a red light flash on the picopsu. I am using a universal adapter to power the picopsu and the adapter is outputting 12V and 300 mA. Can anyone tell me what the problem might be?
Nevermind, the problem lied within the universal adapter. I'm assuming too many amps. Although I am wondering, how many amps will the picopsu take as well as the dreamcast itself.
Your universal adapter is not powerful enough. The Dreamcast needs well over 300 mA. I have tried it with a 12v 500ma power supply and it didn't work. You need one that outputs at least 1 amp. That's enough to make sure it runs no problem. The dreamcast will only use as much amps as it needs so using a power supply that outputs 1 amp the dreamcast will only draw what it needs. You may even be able to get your screen running on the same power adapter if the screen is LED modded. So just use a higher rated power adapter to power everything.
That should probably be updated as the Dreamcast definitely doesn't draw 3+ amps. Family guy ran his Dreamcast with a non LED modded screen for 70 minutes on a 2400 mah battery. If what was said in that link was true then his set up should have lasted for 30 minutes or so.
Thanks for the info guys. I found a 12V 2A adapter to an external HD and it worked perfectly. And yes I believe Werd is correct on the amperage. If 2A is enough, I'm sure 3.5A is far over the necessary amount.