Thread: External usb 2.0 DVD ROM

Originally Posted by SpecialK

Hi, im wondering how to hook up the power to a external dvd rom that i put in my, lets say glove box, and i want to run the usb 2 to my mobo with the computer in the trunk. I have a pw70 power supply. How does this work?

You will need to supply 5VDC and 12VDC to the DVD ROM and 5V to the IDE to USB2.0 convertor board in the enclosure. The external enclosure will most likely have an internal AC to DC power supply. I removed the AC supply and supplied 5VDC & 12VDC with two switching regulators (12V: TI PT5071, 5V: TI PT6212) however you can tap 5V & 12V from your PW70. 5V is the red wire(s) and 12V is yellow. I also installed a switch so I can remove power to the DVD rom when not in use. Make sure the PW70 can supply enough current on the 12V rail for the harddrive and the DVD rom...I use a PW60 and when I run both from the PW60 12V rail it has problems, that is why I used the external regulators.

An alternative for those less electronically inclined (like me) would be to take a regular 4 pin molex Y power cable. They're cheap and readily available (even radio Shack has them). You usually use them for adding another power connector onto your PC power supply when you have too many devices. Know what I mean?

Anyway, cut one of the ends off the Y. Not too close to the molex, as you're gonna need a little wire. Go half way between the connectors to be safe. Strip the ends of the four wires on both pieces. Using wire nuts, patch in lengths of wire so that it will reach from your PC to the drive. Try to use wire that is the same gage as the Y cable, and be careful to tie the same color wires together. Run the wires (probably the hardest part) and wire-nut the end that you cut off back on the far end. Basically making a Y cable with one very long end. The short end you can patch between the power supply and an existing device (like your hard drive) and the long end will run to your optical drive.

When you wire together the optical drive end, be sure to put an additional 2 wires on the 5v and matching ground. You can wire these two to the IDE/USB converter for power.

Now you have regulated power to your optical drive without having to mess with more power regulators/inverters and all that stuff. Also it's modular. If you change power supplies or drives all you have to do is unplug the Y cable and reconnect it to the new device.