DC PSU Pins

[Beak]

On the DC PSU board, where are the PSU pins?

I realize it's a simple thing, but I don't know which way is up when it comes to electronics.

[Hobie-wan]

There's the translucent block with 6 pins that stick up through from mobo underneath in the bottom left. You should see 5v and 12v printed on the board around it.

[Beak]

Thanks a lot.

So if I were putting another LED (3.3v) in my Dreamcast, I would attach the positive to the 1st pin and the negative to the 3rd, right?

How would I attach those wires? I've never done this before.

[Hobie-wan]

Well, I believe pin 1 is 5 volts, so if its a 3.3 volt led you're going to burn it out. You could perhaps piggyback off the power led that's already there if its lower voltage like that. I'd check for led mods online. Surely someone's done a DC or even any other console would help you get a better idea how to set it up.

[hailrazer]

The Dreamcast PSU has a 3.3v line on it. It is pin #1.

http://mc.pp.se/dc/psu.html

[ClaymoreClay]

By a "3.3V" LED I am assuming you mean a blue LED that has a voltage drop of 3.3 volts running at 20mA. If this is true then you need to hook up the LED to a voltage source that is greater than its voltage drop. 5 volts will work fine. You must also hook up a current limiting resistor in series with the LED. I will upload a schematic. The resistor needs to be 85 ohms. The two nearest standard values are 82 and 91 ohms. The resistor needs to be 1/4 watt. I haven't looked at a DC power supply before so I'm not sure what is the best way to hook this up. If you have a picture I may be able help. If want see how I calculated this just ask and I will post my math. The negative pin on the LED is attached to the resistor which is attached to negative power supply pin. The positive pin of the LED is attached to the positive power supply pin. I recommend getting the resistor from radio shack. Shipping will cost too much if you buy it on line.

[Beak]

Okay, so I should be attaching it to the 5 volt pin?

The only thing I could find on the internet about DC LED mods was this: http://www.youtube.com/watch?v=emDj0pRw7w8 (make sure to mute the sound, it's kind of annoying).

Unless I'm daft, which is likely, this guy doesn't seem to be using any extra resistor.



This is about the only picture I could find on the webs. I'd post a picture of mine, but I don't have a working camera. Hope this helps.

[ClaymoreClay]

About the resistor, most people can get away without using it because they hook it up to a low voltage. Since the voltage is so low after the voltage drop the contact resistance from hooking it up is enough to act like a resistor. But with 5 volts you will most likely burn out the LED if you do not have a current limiting resistor. You can try it without the resistor on the 3.3 voltage but it may not be enough since the LED's voltage drop is around 3.3v. If the 3.3v doesn't work then try the 5 volt on the supply (with the resistor).

Moving on to hooking the LED up, from the picture you posted Beak it looks like the pins on the power supply are something like Molex connectors. The only thing I can think of that wouldn't involve spicing the wires is to put the wire directly in the plastic crimp that plugs into the Power supply board. You could use tape to hold it together.
Hope this helps.

[Beak]

Okay! I will try that once I get all the parts I need. Thanks everyone.

[Niode]

ClaymoreClay, if you didn't know the pins on the power supply that provide power to the rest of the board (the ones that I think beak is referring to) is the row right at the top of the picture in the previous post. It's 4 pins that come from the motherboard and slide right through the PSU board. That picture is actually upside down, if you look inside a DC with the controller ports facing you, the pins are at the front of the console.

You can actually see the pins better in this pic:



They're in the top left of the image in front of the 3 ceramic caps.