-ct- Posted May 28, 2003 Share Posted May 28, 2003 so anyway, i have this idea for a modi want to put 4 micro-atx boards in a single atx case (ok, it's an old vectra 500 that i can hack up)there's space for 3 cdroms, and a floppyso i'll have space for 4 laptop drives and a cdromthe problem i am coming into right away is powerthere's not enough space for 4 atx psushere's how it's layed out:the board is vertical on the LEFT side of the case, with a riser card horizontal for isa/pci slots (the 4 new boards would go vertical as if they were the expansion cards, but that whole system will be removed of course)the hdd cage (space for 2 3.5") is right below the riser card, which is bolted to a metal "shelf", and the power supply is below the hdd cage the space for the cdroms and the floppy is in front of the hdd cage and psuso - there's space for ONE full sized atx psu in therehow can i, or CAN i - split the power supply to power all 4 boards, drives, and cdrom?i have plenty of molex conectors of the right type, but i need to know if this is something that CAN be done before i go and start hacking awayin a related question - how can i share the single cdrom between all 4 boards? this sounds like a bit trickier problem than simple poweri'm almost sure i can't do that, and 4 laptop cdrom drives would be better, but the whole point of this excercise is to NOT spend any more $ than i have to4 boards, 4 cpu, and 4 sticks of ram ($500 or so) are needed to complete this missioneverything else is in stockideas anyone? Quote Link to comment Share on other sites More sharing options...
greengeek Posted May 28, 2003 Share Posted May 28, 2003 Why are you doing this?Is it going to be one big computer with four motherboards and CPUs?You'd need four video cards unless the boards have on board video. Even though they are all in the one case, you are really going to have four computers which means four operating systems.Keep you out of mischief anyway. Good luck with it. Quote Link to comment Share on other sites More sharing options...
ChrisP Posted May 28, 2003 Share Posted May 28, 2003 Some more info is needed...For example, do you intend to attempt to run more than one mobo at a time? Any connection scheme short of using a "selector switch" would likely cause more problems than you want, as each of the individual feeds from the PSU would end up feeding multiple parallel circuits.Modern power supplies are designed with a couple of important factors in mind (among others, of course): maximum current to be drawn on the various outputs, and minimum current to be drawn on the various outputs. The maximum current to be provided by a given supply must be at least equal to the maximum current required by the various circuits to be powered by that supply. That much is pretty self-evident, right? The minimum current is another story. Most modern switching power supplies require a certain minimum current draw (i.e. load) on (usually) one of its outputs -- normally the +5VDC output -- in order for the supply to successfully start. In many cases, this "start-up load" is provided by way of a resistor inside the PSU. The value of this resistor is selected to provide for adequate starting load when the external load connected to the PSU is what would be found with the range of devices normally found in a PC.Did you ever have an experience wherein a given PSU would work fine in one PC, but would not even seem to be able to start another system? This is often caused by the external load on startup. In a DC circuit, two resistances taken in parallel will have the net effect of reducing the overall circuit resistance. For example, two 100 ohm resistors connected in parallel will have an effective resistance of 50 ohms. The formula for this is known as "the product over the sum" -- RTOTAL = (R1 x R2) / (R1 + R2). Using this formula and the two 100 ohms resistors mentioned above, (100 x 100) / (100 + 100) = 10000 / 200 = 50 ohms.OK -- here's where it can get interesting. Better switching supplies used in PC's will shut down if the current draw is too high, and they won't start up if the current draw is too low! Did you ever notice what happens if you misconnect the power connector to a floppy drive? With a quality PSU, it will immediately sense the over-current condition and shut down. Of course, a PSU that is of lesser quality may just deliver current into that dead short until the PSU dies.Connecting multiple mainboards in parallel to a single PSU will drastically alter the startup current draw (startup load). Using a switching scheme that isolates the individual output lines is possible, but then the power supply should have its AC input removed when making the "board selection" via any switch scheme. This is because of the fact that ATX boards draw current from ATX supplies whenever the AC input is available. Switching the supply to the mainboards with the AC input active would be similar to unplugging and reconnecting the ATX mainboard power connector with power applied -- hardly a recommended action.There's really a lot more to consider in this endeavor -- I just touched briefly on a couple of considerations that popped into mind. Quote Link to comment Share on other sites More sharing options...
-ct- Posted May 29, 2003 Author Share Posted May 29, 2003 great info, chrisp :)quite detailed as far as it goes and i'm sure that i can find out what i need from thereso, in effect, the short answer is "no 4 boards on one psu"does anyone have ideas about an atx psu that is 1/4 the size of a standard one, so i can fit 4 of them in a space the size of a normal one? it doesn't have to be 550watts, just enough to run a board/cpu and a laptop drivei have seen some 180w micro-atx psus, but they are still a bit too big to fit in the space availablegreengeek - thats exactly what i want to do, have 4 pc's running in the same boxthey all have onboard vid and the cpus are onboard as well (fanless, no heatsink - think the new via boards will do fine)as for WHY, well, just like eddy said "because it's there" ;)on the second Q: is there a way to split 1 cdrom between 4 systems? Quote Link to comment Share on other sites More sharing options...
greengeek Posted May 30, 2003 Share Posted May 30, 2003 You'd need some sort of custom made IDE cable to use one CD drive on four motherboards, one end to plug into the CD and four ends for the motherboards. Quote Link to comment Share on other sites More sharing options...
pro-surfer Posted May 30, 2003 Share Posted May 30, 2003 Case modding is funThis is interesting for certain.There are switch-able cable connectors for IDE cables – you will need that for sure as ‘greengeek’ mentions. I have only seen a 2-way switch but if you are doing all this yourself just find a pin-out diagram & get busy with a soldering iron & the best rotary type switch that meets the needs.I don’t have the sights bookmarked but I would ask Mr. Google to find you parts & supplies for mini form factor comps like “shuttle†They have miniaturized everything. I think that will be your route to the psu crisis. Here are some sights to get you moving along:http://www.mini-itx.com/http://www.via.com.tw/en/VInternet/mini_itx.jsphttp://www.pcguide.com/ref/case/formATX-c.htmlhttp://www.accessmicro.com/minipc/index.phtmlJust a few suggestions Quote Link to comment Share on other sites More sharing options...
Marsden11 Posted May 30, 2003 Share Posted May 30, 2003 Why not look at 1U power supplies from 1U rack mount cases? They are pricey! Quote Link to comment Share on other sites More sharing options...
muckshifter Posted May 30, 2003 Share Posted May 30, 2003 Why do you have to fit the PSU inside the case? Quote Link to comment Share on other sites More sharing options...
FuzzButt Posted May 30, 2003 Share Posted May 30, 2003 True the 1u Power Supplies are smaller abd seems any part that is for industrial PC's is much more expensive.Why not set your sights a bit lower? 2 complete systems in 1 box would be where I would start if I have that much time to kill. It would be much easier place to start.Of course I would not be doing this unless it was going to be worth my while. I would surely have top notch components inside. Even with my massive Lian-Li PC71 case I don't have room for a complete second system except for another power supply.Maybe a few pictures might help us imagine what it is that you are tying to do. These sound like some serious mod's that might be beyond the scope of possibilities.Chris Quote Link to comment Share on other sites More sharing options...
-ct- Posted June 1, 2003 Author Share Posted June 1, 2003 it started life as a novell server for a restaraunt, now it's minethe 1st image is the pc itself, many of you will recognize it :)the 2nd and 3rd show the insides imagine instead of where the PCI/ISA cards are, there would be mainboardsthe current mobo and riser card removed of course and the back end of the case from the riser card up severly hacked, probably just cut off completely and rebuilt from scratchi LIKE this case, it's KEWL how the door goes in and up/down, but the system is just not gonna cut it so i wanna keep the case and remake it into a superserver and paint itprobably add a few windows and lights Quote Link to comment Share on other sites More sharing options...
FuzzButt Posted June 1, 2003 Share Posted June 1, 2003 Interesting.That case is basically the same size as my full tower Lian-Li case. I have see larger HP cases that would have much more room in them for what you want to do. For instance the HP LHII that I work on almost daily is much bigger than the Vectra case. As is the other PC that we use the HP LC2000. The LHII's case is nearly double the width of your vectra anbd just about as tall. It has room for 2 power supplies or 3 if you remove a fan. There is room for 6 plug-in style SCSI hard drives and 3 external bay's. The LC2000 differs as it is more than 10 inchehs deeper but not as wide and is all PCI based. Either way I see what it is you are trying to do to that case. I would just try to 2 system approach and leave it at that. Much less complicated and it is still way up on the cool factor. What would be more fun is to take a large custom case and modify it to take 4 babyATX or Flex ATX boards and go that route. kind of like taking 4 of those little Shuttle PC's and stuffing them into 1 case. That way with the use of a KVM you could be running WinXP, Win2K, Win98SE and Linux all at the same time in the same case. A few years ago I interviewed at a up and comming Long Distance Phone company. I saw something odd in the processing room. There was 8 Compaq ProLiant servers all connected together for a distributed processing job. At the time I thought that was quite cool. Seeing as how PC currently have as much processing as 8 Pentium Pro's at 166MHz had at that time. You know the company I used to work for had a perfect PC I always wonder what happened to it after we were bought. There was an 8 or 16 processor (8 were active) AS/400 that was just awsume. I wish I had pictures of it. It was 36" tall and 42"deep and 48" wide. It sure would have been cool to look inside. I know the storage array was interesting. We had to replace a spool drive that weighed more than 100 lbs.Oh well my wifey is calling for dinner.Chris Quote Link to comment Share on other sites More sharing options...
-ct- Posted June 2, 2003 Author Share Posted June 2, 2003 Interesting.That case is basically the same size... (yada yada yada (...What would be more fun is to take a large custom case and modify it to take 4 babyATX or Flex ATX boards and go that route. kind of like taking 4 of those little Shuttle PC's and stuffing them into 1 case. That way with the use of a KVM you could be running WinXP, Win2K, Win98SE and Linux all at the same time in the same case. ....Christhe case really isn't any bigger than a standard midtower atx case, but it's the configuration of the interior that puts the limits oni have at least 3 FULLtower cases available (about 2'4" tall) and i can fit at least 8 microatx systems in any of them, but i want to use THIS caseit looks far better and is in better shape tooexactly what i want to do! babyatx are too big with all the extra uneeded slots, 4 microatx boards (flex, shuttle, etc) will fit in this easy, (and maybe 5 if i use via boards -they have no heatsinks) and a 4 port kvm can fit in there, taking the space of the 2 lower cdrom spaces (or upper one and floppy bay - who needs a floppy these days anyway?)getting 4 complete systems in this case is the way i wanna do it, the only major question is POWER to the boardsso - how do i get power to 4 boards in the same space as a standard atx psu, without spending mind-boggling amounts of $?all i need is 4 boards and power, everything else is on-hand alreadybudget is $500 total and not a dime over that Quote Link to comment Share on other sites More sharing options...
Marsden11 Posted June 2, 2003 Share Posted June 2, 2003 so - how do i get power to 4 boards in the same space as a standard atx psu, without spending mind-boggling amounts of $?Basically your not! That is the reality. You would need to start and design a PS from the ground up to power 4 ATX motherboards or micro boards for that matter. Cram 4 boards in that tiny case and how will you deal with all the heat?Sounds like you want a "blade server." There is a reason they are expensive...Think it through... you will need to hook up 4 mice, keyboards, monitors. That is a bit much so you go with a KVM... there is an extra cost. So what you really want is a "headless" setup. Access to all 4 machines is via IP so you'll need boards with intergrated LAN... remember you will not have room for cards... Quote Link to comment Share on other sites More sharing options...
-ct- Posted June 2, 2003 Author Share Posted June 2, 2003 and just how many microatx boards DON'T come with onboard lan/sound/vid/etc?the heat on via's boards is practially non-existant, they don't even have heatsinksshuttle's boards use standard sinks/fans and there's enough space to stack 4 boards plus hsf eachand, there is plenty of space for a few case fans to be added in there - not a problem, so we're back to power :(i won't be needing to add cards of any kind, as the boards are going to have everything needed onboardheadless setup might not be a bad idea - it would save space in my shop and i could put the unit in the showroom as a working display Quote Link to comment Share on other sites More sharing options...
Marsden11 Posted June 3, 2003 Share Posted June 3, 2003 And the micro-ATX boards are usually placed in tiny enclosures to allow for easier heat transfer to the outside of the case. So you are going to have 4 boards with CPUs in a single enclosure with 4 hard drives and a bunch of CD-drives. You figure a couple of case fans will do the trick. OKHave you looked at a 1U rack mount case and observed how they deal with air flow? There is usually 1 or 2 high powered fans blowing cool air through a duct that covers the CPU/CPUs. The other one or two fans blows cool air over the hard drive/s and power supply. They are usually loud as ****. But you feel that a couple of case fans will be enough... I think all they will do is blow the hot air around.You have solved the problem of cards... Quote Link to comment Share on other sites More sharing options...
-ct- Posted June 3, 2003 Author Share Posted June 3, 2003 1 cdrom (still trying to figure a way to share it between 4 systems), 4 laptop hard drives and there's plenty of space to add fans for airflow through the case, not to mention the windows (with fans) that i'll be addingspace for the mobo, cdrom, and drives just isn't an issuespace to put enough power supply(s) IS Quote Link to comment Share on other sites More sharing options...
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