You are in luck. This old style power supply (PS) is much simpler to make work and generally the case is larger so you have more room to work. Plug in the power supply and turn it on. The fan should be running. Use your VOM and identify the correct color pair of wires for +12 volts. This is fairly easy. Pick a set of wires that ends in a plug with only 4 wires. This probably went to a disk drive (either hard disk or floppy). There will be 2 center wires the same color (probably black) and the outside wires will be different colors (perhaps yellow and red). Use the VOM with one probe in a center wire and one probe in an outside wire. What you will find is that the center wires equate to a negative post on a battery and the outside wires are the positive posts. With enough trial and error you can identify most of the colors. Ones that I have seen are:

Yellow +12 volts

Black Common

Red +5 volts

Orange -5 volts

Blue -12 volts

White Power good .

There will be a lot of +12 volt wires, a lot of +5 volt wires, an awful lot of "Common" wires and only one or two -12 volt or -5 volt wires. Normally there is only one "Power Good" wire.

Now that you know which color is +12 volts and which is "Common" all you need to do is "design" your box. Since we plan to use this power supply as a substitute for a car battery I envision it with "Positive" and "Negative" posts, just like a battery. Pick two locations on the PS case that will allow your charger to be clipped onto without shorting out, and that you can run several wires to the inside of the PS case to those locations. Go to the local hardware store and get:

2 rubber grommets (1/4 inch center holes is fine)

2 #10 machine bolts 1 1/2 inches long (these should go through the grommets without problem)

4 nuts for the bolts

4 flat washers for the bolts

4 large (probably 1/4 inch by 2 inch diameter) nylon (or other insulating) washers with small (1/4 inch) holes in center

Now back at the shop. If you happen to have some Red Zagi tape and some Black Zagi tape then cover one side of a Nylon washer with Red and one side of another Nylon washer with Black. Trim the tape from the uncovered side with a sharp knife. Drill a 5/16 hole at each of your chosen locations. Put a rubber grommet in each hole. Next cut 3 or 4 of the +12 volt wires to length to reach the first hole. Solder these wires to the bolt (near the head). "Ring terminals" are an excellent option rather than soldering directly to the bolt but either route will work. Put a nut on the bolt and tighten it against the soldered wires. Put a metal flat washer on the bolt. Next put one of the nylon washers on the bolt. Shove the bolt through the grommet. If necessary you can trim the nylon washer a bit if it conflicts with something but leave enough of the nylon washer to be sure the wires do not contact the PS case. Put another nylon washer (the Red one if you covered one with Zagi tape) on the bolt. Put another metal flat washer on the bolt. Put another nut on the bolt and tighten it up. You now should have "Positive" battery post that is fully insulated from the PS case.

Next cut 3 or 4 of the "Common" wires to length to reach the second hole. Repeat the same process you did with the plus 12 volt wires this time using "Common" wires. Use the Black Nylon washer on this one if you covered one with Zagi tape. You now have the "Negative" post for your new PS. Now all that is left is to cut off the excess wires such that they will not short out. Put the cover back on the power supply and mark the posts as "Positive" and "Negative". You are done.

This power supply (PS) is a bit more complicated than the older ones and requires a bit more work. Not only that they tend to be smaller and there is less room to work inside the PS box.

Plug in the power supply and turn it on. The fan may be running or it may just start and then stop. Generally the following colors will identify specific functions - generally:

Yellow +12 volts

Black Common

Red +5 volts

Orange Power good

Blue -12 volts

White -5 volts

Green or Grey Power Supply – On (PS-on)

Note: "PS-on" may not exist. If it exists it will be part of the double rowed plug that went to the motherboard of the PC.

If the fan is not running consistently turn the power off and temporarily connect "Power Good" to a +5 volt line. This should cause the fan to run consistently when the PS is turned on. If the fan is still not running you should look for the "PS-on" line and connect it to a "Common" line. The PS-on line is in fact a switch to turn on (or off) the PS. Use your VOM and identify the correct color pair of wires for +12 volts. This is fairly easy. Pick a set of wires that ends in a plug with only 4 wires. This probably went to a disk drive (either hard disk or floppy). There will be 2 center wires the same color (probably black) and the outside wires will be different colors (perhaps yellow and red). Use the VOM with one probe in a center wire and one probe in an outside wire. What you will find is that the center wires equate to a negative post on a battery and the outside wires are the positive posts. With enough trial and error you can identify most of the colors. There will be a lot of +12 volt wires, a lot of +5 volt wires, an awful lot of "Common" wires and only one or two -12 volt or -5 volt wires. Normally there is only one "Power Good" and one PS-on wire.

Make the connection from "Power Good" to +5 volts a permanent connection (solder it with a bit of heat shrink).

Now that you know which color is +12 volts and which is "Common" , next you need to "design" your box. Since we plan to use this power supply as a substitute for a car battery I envision it with "Positive" and "Negative" posts, just like a battery. Pick two locations on the PS case that will allow your charger to be clipped onto without shorting out, and that you can run several wires to the inside of the PS case to those locations.

You may wish to move the PS power switch into the case if it is an "umbilical" cord type switch. I normally choose to move it into the hole that the "umbilical" cord comes out of the PS case through. This process is just a matter of unsoldering the wires, shortening them and re-soldering them. Be sure to solder the right same colored wires back onto the same lugs on the switch. You will probably need to drill a couple of mounting holes in the PS case to hold the switch and mount the switch using these holes and a screw through each.

Go to the local hardware store and get:

2 rubber grommets (1/4 inch center holes is fine)

2 #10 machine bolts 1 1/2 inches long (these should go through the grommets without problem)

4 nuts for the bolts

4 flat washers for the bolts

4 large (probably 1/4 inch by 2 inch diameter) nylon (or other insulating) washers with small (1/4 inch) holes in center

A 12 volt automotive light with a socket and wires (I use a small clearance type light with amber lens). A #1154 or #1156 bulb also works well.

Now back at the shop. If you happen to have some Red Zagi tape and some Black Zagi tape then cover one side of a Nylon washer with Red and one side of another Nylon washer with Black. Trim the tape from the uncovered side with a sharp knife. Drill a 5/16 hole at each of your chosen locations. Put a rubber grommet in each hole. Next cut 3 or 4 of the +12 volt wires to length to reach the first hole. Solder these wires to the bolt (near the head). "Ring terminals" are an excellent option rather than soldering directly to the bolt but either route will work. Put a nut on the bolt and tighten it against the soldered wires. Put a metal flat washer on the bolt. Next put one of the nylon washers on the bolt. Shove the bolt through the grommet. . If necessary you can trim the nylon washer a bit if it conflicts with something inside the PS case but leave enough of the nylon washer to be sure the wires do not contact the PS case. Put another nylon washer on the bolt (use the Red Nylon washer if you covered one with Zagi tape). Put another metal flat washer on the bolt. Put another nut on the bolt and tighten it up. You now should have "Positive" battery post that is fully insulated from the PS case.

NNext cut 3 or 4 of the "Common" wires to length to reach the second hole. Repeat the same process you did with the plus 12 volt wires this time using "Common" wires. Use the Black Nylon washer on this one if you covered one with Zagi tape. You now have the "Negative" post for your new PS.