Time for an upgrade! My previous ATX bench supply was without me knowing it causing all sorts of video issues. After identifying the problem, it was time to get a new one, and I've picked up a Cooler Master MasterWatt 650W. ATX power for arcade is just fine, but using an old beat-up recycled thing may not be ideal unless you have a way to verify that is's working ok. A multi-meter will not do the trick unfortunately.
You're never going to need 650W, but the nice thing is that even with ~5A on the 5V rail, which is about as much as you will ever see - it stays quiet with no fan activity. Also nice with this one is that it doesn't have a ton of cables/connectors attached, and that the 24pin cable is a little longer than normal. The ad for it says 16AWG, which turned out to be bogus - the 24pin is plain 18AWG.
Scope time
This was the root cause of issues I had with the old one, ripple about 0.17V when loaded ~ 4A:
This is the cooler master, with a ripple of about 30mv, or 0.03V which is really good:
For reference, same setup with my linear Rigol DP831 fancy lab supply:
You're never going to need 650W, but the nice thing is that even with ~5A on the 5V rail, which is about as much as you will ever see - it stays quiet with no fan activity. Also nice with this one is that it doesn't have a ton of cables/connectors attached, and that the 24pin cable is a little longer than normal. The ad for it says 16AWG, which turned out to be bogus - the 24pin is plain 18AWG.
Scope time
This was the root cause of issues I had with the old one, ripple about 0.17V when loaded ~ 4A:
This is the cooler master, with a ripple of about 30mv, or 0.03V which is really good:
For reference, same setup with my linear Rigol DP831 fancy lab supply: