All you need is to connect those connectors to the power switch. I guess the old one has four because all the power from the PSU needs to run through the switch, and by dividing the current in two pairs of wires/contacts there is a lower risk of those wires getting overloaded. Just connect them to oposing contacts and it should be fine.

Disconnect old AT PSU first from mains plug, then you can safely disconnect the four wires going to the switch (blue,white, etc).
Then connect the ATX adapter green/black to any two that work, you cannot break it. Based on the video I guess the pins with blue and white that are side by side on the foreground, or the other two (black/brown? I can't see) on the background. Leave other two disconnected. If you have a multimeter, you can check which two are connected together when switch is on. The switch is supposed to connect ATX supply black (ground) and green (PSU_ON) wires together to turn the ATX supply on.

alexanrs wrote:

I guess the old one has four because all the power from the PSU needs to run through the switch, and by dividing the current in two pairs of wires/contacts there is a lower risk of those wires getting overloaded.

No, it's to prevent you to get killed by electricity. Actually same current flows in both halves of the switch, but in opposite directions. In some parts of the world, your mains plug can be either way in the socket so which wire is live (has lethal AC voltage) and which wire is neutral (zero voltage) is unknown, so you have to switch both wires before it is safe. Compare this to common light switch in your living room which only switches one wire. The electrician has to make sure the switch cuts the live wire, so that when you turn the switch off, it is safe to change the light bulb. If the switch accidentally cuts the neutral wire instead, and you change the light bulb and accidentally touch the lethal AC voltage and something else that is grounded, you get a shock.

Thanks you guys, I do feel silly now actually, I just spent an hour with tech support figuring it out. (You guys were faster!) Why didn't I get an email for the replies?

Anyway, I'm currently trying to disconnect the blade connectors, but they're really gripping, I'd guess from having 120V in them for 20 years. Any tips for disconnecting them without hurting myself or anything? I got the rear wires off, just not the AC wires so far.

Oh, and while I'm at it, doing all this reminded me of an old joke. (Stop me if you've heard this!)

Why are the AC wires brown and blue? Touch them or connect them wrong and YOU will be! (I've actually heard stories of peoples' houses being completely shorted from connecting the switch wrong.)

Jepael wrote:

No, it's to prevent you to get killed by electricity. Actually same current flows in both halves of the switch, but in opposite directions. In some parts of the world, your mains plug can be either way in the socket so which wire is live (has lethal AC voltage) and which wire is neutral (zero voltage) is unknown, so you have to switch both wires before it is safe. Compare this to common light switch in your living room which only switches one wire. The electrician has to make sure the switch cuts the live wire, so that when you turn the switch off, it is safe to change the light bulb. If the switch accidentally cuts the neutral wire instead, and you change the light bulb and accidentally touch the lethal AC voltage and something else that is grounded, you get a shock.

Here where I live there is no such a thing as a neutral wire. Both are 127V DC (delayed 120º from each other, thus the voltage between them is ~220V), so both are live wires. I guess this would make even more sense in this case.

georgeqgreg wrote:

Thanks you guys, I do feel silly now actually, I just spent an hour with tech support figuring it out. (You guys were faster!) Why didn't I get an email for the replies?

You don't get e-mails for replies automatically. You'll have to check "notify me when a reply is posted" to get them, and I never checked if that works.

I have notifications for replies enabled, so I guess they're broken.

Anyway, here in Canada (we use the same system as US) we have a neutral wire. Also our electrical system is one of the dumbest in the world. There's almost no safety features or anything. Anyway, I'm getting real tired trying to yank the AC wires out. Any tips?

Ok, only the blue wire is still connected. I swear, it looks rusted or something.

OK OK I JU?ST PRIED IT OUT WITH A FLATHEAD SCREWDRIVER. (Kids, don't try this at home.)

Addendum to me never getting an email for this topic. THANKS GMAIL. http://imgur.com/T45aKUL

OMG GMAIL IS SMART!
Btw, did everything work okay with the ATX PSU?

So far, so good. I've had Windows 95, Windows 3.1, and DOS 6.22 in various states of working. Might make another topic with my remarks on the system as a whole.