Can I do this connection ??

[MrPoPo]

Hi group !!

I want to plug a Dreamcast into my Arcade Machine.
Can I damage any component if I do this ??

[grafixmonkey]

What, you're wanting to switch power between the DC and the PC?  If I were adding a switch like that, I would use a double pole switch and switch both contacts.  Otherwise you might have the live wire still connected to the PC or DC, and just eliminate the neutral wire.  

You can get one switch that will switch both contacts at once, that's better.  And don't forget to connect the ground wire to both, I believe nasty things can happen to a PC gradually over time if the ground wire isn't connected.  (gradual buildup of static electricity in silicon substrates is what I think happens, as well as any static electricity that goes into the case wall having to spark into something that matters instead of sparking to ground.)

[grafixmonkey]

By the way, why are you doing this?  unless you're running DOS you shouldn't be offing the power to the PC without shutting down, and you'll have to switch something anyway so you might as well switch the dreamcast.

Also, I think you mistakenly made the VGA line run into the IPAC.  Two things...  I think I remember hearing posts about using diodes to make the double-connection to DC and IPAC work properly.  And, if you simply plug your VGA output cables into a Y-adapter without a switch to switch between them, that could be bad.  No problem if only one is on at any given time, but you might experience image quality loss of some kind, and if both are ever on at the same time you'd have two line-drivers trying to drive the same line at the same time (can be bad for the line-drivers).

[MrPoPo]

Tank you.

Can you remember where you read the posts about double-connection to DC and IPAC ??

[grafixmonkey]

on this forum somewhere.   frequently too...
but sorry, do the search yourself...