I have noticed that all ribbon cables are marked down one edge with a red band. I have been examining all of my computers, both mac and PC, and it seems that there is a convention to the way they must be attached, both on the board and on the device they power. so far I seem to deduce that the red edge always seems to face towards the inside of the machine and also face the plug where the power supply wires go into the device as well.
is this correct? for that matter, it appears that the four-wire power plugs, ( those having one yellow, 2 black in the center, and one red), always orient so that the red is to the interior of the machine, and the yellow is oriented to the outside, nearer the 'skin'. am I grasping the right idea? what does the red band down the edge of a ribbon cable stand for? is that 'positive'? is there a notation on the logic board or the the back of the device that I should look for, that indicates which side the red band should be on when it plug in? what should it say? I did notice that there are not actualy 40 pins on the ribbon: there are 39, and one blank space. I matched up the missing pin with the filled in space, and figured that was the clue to the right way to plug it in. if my belief (that red always goes towards the center and yellow always goes toward the outside) is correct, then does the same hold true when plugging the other end of the ribbon cable onto the logic board?? should the red band always orient on the logic board to be on the side more to the center?? I only see the missing pin and filled hole, to go by, at this point. Ya see,... I took my kid's PC apart today, yup, uh huh-- completely, down to the frame, and carefully reassembled it, piece by piece over into the case of the beautiful 486 tower with the 300 watt power supply. I took out the motherboard with the 486 and began again with my kid's Dad's 6x86. board, and recreated it in a bigger case. I made diagrams and studies as I went, to be sure I got everything connected back up the way it should be. But I missed that one detail. I took the ribbon cables out of their sockets on the board, before I remembered to draw what I saw beforehand. So I need a prompt, as to how to be sure I get the red edges inserted back on the board in the right direction, before i ever try powering up. I feel pretty good about the project so far. Everything is going well. I think I found the cause of its failure to turn on, when we got it in the mail: the bashed- in case translated the impact inside, to the seating of the add-on cards, and jarred them up out of their slots. When I pulled them off the board to await transfer, they gave zero resistance coming out. when I got ready to put them back on the logic board in the new case, they sank much deeper into their slots and grabbed in there, but good. so I don't think they were making contact, before. everything in the old one fits nicely in the new one. i need one bezel snap-in panel for the floppy drive, to make the faceplate look right. will get that tomorrow at the computer fair. Now that I've transferred everything, I find I'l need a longer IDE ribbon cable 40 pin, to reach from the CD rom drive, down to the logic board. the old one stops just millimeters shy of the socket. So I'll get one of those. Turns out I need a new floppie ribbon too. I found out the edge caught on something sharp, god-knows-when, and severed the outermost wire. So I'll take *that* with me to the fair and get an identical one, too. A question about grounding: the add-on cards fit more tightly in the new case, and in some places, it looks as if the collars around the dongles touch or rub against the cutouts in the back, where you screw them to the case. is this going to be a problem, with grounding or making good contact, etc? mystery question,-- for those of you who know how to connect the main power supply lines to a PC board: out from the powerbox come two sets of wires: one bundle forms groups all of four wires each, each rope colored red- black- black- yellow. Then there's another group, with 5 wires to a rope, two of them-- with differing collections of colors. one has three red and two black. the other has black, white, yellow and blue. I *do* know that "black always goes down the center".( noticed that earlier). the mystery is: when I plug these into the logic board, to give it its powersupply, which way do the bank of them face? i know enough to set them side by side with black in the center, but they plug onto the board, on a formation of pins, that looks like a single file of columns in front of a single high wall. the pins are big ,thick tongues of contact metal, compared to the skinny little pins you see on Hard drives or floppies or LED's. There is a plastic snap tab, or tongue, on one side only ,of each of the two 5-wire power cord ends, that I can see go on the logic board. Problem is, I can't figure out whether to turn those tabs towards the high side of the socket, the 'wall' side--or whether they face the low side, and snap in. anybody know what I'm talking about, here? I need to know, so I don't fry the board. the old power supply was 250 watts. the one in this box is 300 watts. Should that hurt anything if I have connected it up right? I think it's 300 watts because this case had a 486 motherboard in it that was set up for 7 long cards and 3 short ones, and I think it was configured to be able to handle all those slots filled in, if desired. the machine I am transferring over into it had fewer cards set on it: that 250 watt supply was driving -a 1 gig Hard drive -a floppy drive -a CD ROM drive -the 686 motherboard -a cooling fan and heatsink on the chip -a modem card -a 2 USB port card [for a webcam] -a video card -a sound card -a printer port -a mouse -the keyboard -a DB-25 female dongle [for--??] -a zip drive -a game port -and has three more slots that could be filled in the future. are there any other specs I should be looking for, on the power supply to be sure that these components can use this 300 watt power supply as well as they used the old 250 watt one? the old one was set at 115 volts [for american]. this one is set at 110 volts [for american] anybody got answers, before the fair dawns tomorrow?? janet -- Vintage Macs is sponsored by <http://lowendmac.com/> and... 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