VOGONS


First post, by BitWrangler

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Hi folks,

Things are coming together for a later "DOS" but extending into early 9x capabilities build. Apologies to anyone actually named Dustin btw. In some respects, this is a "dream rig" in that since I first started messing with PCs in the 90s, I've always wanted to put a machine into a small enclosure... abusing non-specialist parts to do so. The mini-ITX stuff doesn't interest me much for instance, because there's not much effort, goes together like lego. However, should I find something that I think "Hey, I wonder if I can cram an ITX board in that...." then maybe ITX will be the new shiny.

It felt like a good time to do this as I found I have a lot of boards.... and a lot of cases... but far more boards than cases, and I don't wanna give up the "good" cases to lower power, less than full width boards, or the old cases to stuff outside their era, when there's gonna be boards of their age looking for a home. So I remembered my old ambition "stuff a PC into a biscuit tin". Now your regular squareish (3lb?) biscuit (cookie) tin of the Rover, Crawfords or Peak Freans variety is just exactly the wrong size for an mATX, it's also exactly the wrong size for the baby AT board I want to use this time around, so you might accuse me of making the entire premise a bit of a crock, when I tell you it's gonna use a slightly larger footprint tin that had chocolates in it. It's also more of a crock that I deem this a bit too shallow for my purposes and therefore I'm gonna extend it to approx biscuit tin like height, maybe 4 inches, 100mm or somewhere near there.

So the tin is about 230mm square while the board is 220mm square, acres of space. (Bear in mind if looking for a tin for a motherboard, they have rounded corners while motherboards do not, unless you wanna get busy with the side cutters and hope they didn't sneak an important line round the outside of the mounting holes) Now the tins of my youth were somewhat sturdy, and this alas is rather ummm tinny.. that is to say thin and flexible, so I'm not sure if when I put mounting posts to the bottom and screw in the board, whether the tin is supporting the board or vice versa. We may be needing extra structure at some point. One really cool vision I had was to use a small offbrand 90s boombox as the entire front panel, (Gutted to just the fascia and speakers maybe using the amp if it was easy to hook in) however, the one I had I thought was small was too big for this, thought it was smaller until I dug it out, and the other possibility dimly remembered because I dunno how I got it and never used it, turned out to be a lopsided mono unit, 2/3 of a boom or something. I can't help thinking that there was a small radio only one around somewhere that might fit the bill, but unless it's exact location suddenly pops into my head, I am proceeding in another direction. I found a plastic part, maybe off an old fridge that has a handle recess that looks like it would cut out nice for a floppy drive, and it's the right width.

I am probably going to raise the lid up on some long standoffs, I believe there are suitable ones around somewhere. Ideally I'd like to be able to stand a 14" LCD on top of this when done, not sure if it's going to need an X across the top inside, or whatever additional material to hold one or not. For closing the gap at sides and back, I'm still undecided, it might depend on which direction the cooling system has to take, possibly it will be a mesh, possibly it will be a panel of some kind. I did think of heatgunning all the components off a scrap board, and using the board, or possibly using some copper clad PCB material I've got plenty of and allowing it to go to a steampunky patina. I thought possibly peel and stick woodgrain over something expedient and ugly, but no, this is a high class build dammit 😉 so backup plan is some real fake imitation marble formica. (Not that counterfeit stuff you see these days)

Okay, shut up BitWrangler stop all the arse-thetical claptrap and tell us the specs. What else to use but the the premier board of it's type, the fastest most high end board that I happen to have in the junk pile and that measures exactly 220mm square with onboard everything, but the mighty M748LMRT... I can tell you are thrilled. I have two, a 1.3A with LAN and a 1.5 without. Not sure which the winner is, do I really want the LAN? Is the 1.5 gonna run a better CPU more betterer? I know DOS machines aren't much of a speed contest but with the SiS graphics dragging butt a bit I want something that pushes a little hard to compensate. Now theoretically I can get a celly 700 working on one of these... in slotket... but I'd rather use the socket.. so hoping a socket mod works. Also theoretically, I could stick in a celly 400 and crank it up to 600... but that would be a tad warm. Yes, you guessed it, I'm just gonna use the onboard sound as well as the onboard graphics. Then a stick of RAM, not sure I need more than 128, might need to watch the power budget because the PSU ain't gonna be large. Thinking 20GB laptop drive and floppy is enough storage. Still pondering the CD question. Possibly I might have the ambition to wire up an adapter for a laptop optical drive.

Cooling is gonna be some wider flatter sink, of which I have some different choices, or I might go for an end blown one if the blower I found starts and runs reliably on 5V, or I guess 7V and is not loud. Got one sink that might manage "passive" cooling if there's a cross draft, which I guess needs a case fan.

Still juggling ideas a bit, will have to see what parts fall into place as things get going.

2017: Basement full of ancient PC stuff, starting to go through it. 2021: Still starting, heh, many setbacks. So what's this BitWrangler guy's deal ??? >>> Taming the pile, specs to target?

Reply 1 of 11, by Caluser2000

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ITS DUSTiN TIMEE!!!! Yee HaAAAw!

There's a glitch in the matrix.
A founding member of the 286 appreciation society.
Apparently 32-bit is dead and nobody likes P4s.
Of course, as always, I'm open to correction...😉

Reply 2 of 11, by BitWrangler

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So here's some beginnings...

Got the mobo thrown precisely into the tin for the pic, the panel to the left I'm thinking of making the front panel out of. To the right there is an old disused docking station, that I'm thinking of robbing of it's section of ports there and wiring all those to headers, instead of taking apart all the headers on card brackets and mounting those. Then down below that we have the real fake imitation marble formica (Genuine article!) that I might be using for side panels. IDK if you can see the outside of the tin is kinda gold, so might actually tie in well.

(Gah, dunno what makes it decide which way round to post the pic, mentally rotate 90 deg anticlockwise, it was all the right way up in my editors.)

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2017: Basement full of ancient PC stuff, starting to go through it. 2021: Still starting, heh, many setbacks. So what's this BitWrangler guy's deal ??? >>> Taming the pile, specs to target?

Reply 3 of 11, by BitWrangler

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PSU only seems to fit in one place... this is with the keyboard connector to the rear. Ignore the green board on the I/O strip, that would come off. I'd be okay with the I/O on the side, but it's got the VGA at the front and the PS/2 mouse at the back which is just wrong. Maybe I want the kb coming out the front, the I/O on the left, then ps/2 is forward and vga to rear, and the PSU will flip over and the wire won't be across the center of the board. However, this puts the CPU more under the floppy, which means a heatsink rethink maybe... unless it still has a cm or so above a low profile fan. Got a slightly shorter sink, but that would need more fan methinks, so might not save height.

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2017: Basement full of ancient PC stuff, starting to go through it. 2021: Still starting, heh, many setbacks. So what's this BitWrangler guy's deal ??? >>> Taming the pile, specs to target?

Reply 5 of 11, by BitWrangler

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Thanks. Current one is 65*80*170 approx, so possibly not worth a purchase for the 30mm in length saving, which isn't really the dimension where it would matter much.

I used to have something about 30mm deep and 120mm square, think it had AT connector, think it was around 120W. Problem with that one is, I can't even remember if it came to this house or not, or whether it was discarded 1, 2 or 3 moves ago. That was probably by Asetec or HiPro who seem to do all the strange ones.

2017: Basement full of ancient PC stuff, starting to go through it. 2021: Still starting, heh, many setbacks. So what's this BitWrangler guy's deal ??? >>> Taming the pile, specs to target?

Reply 6 of 11, by BitWrangler

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Been playing some more three dimensional Tetris.... I've gone cold on having the ports on the side, it keeps it from slotting into space on a shelf between other systems etc and staying usable. Ideally the sides should be completely clean. It looks however, that if I want an optical drive though, that that is the only place to put one. But having the optical blocked in doesn't stop you using the computer at all, like having the vga and ps/2 ports cut off would. Optical started to feel more necessary when I remembered that all the DVD players in the house have issues and there's nothing I can hook up to a TV if I want to watch DVDs... unless I build this like that. One has a VGA port, or the SiS chipset might work with a VGA TV convertor published online. However, in the interests of getting anything at all done on this any time soon, the optical might have to be a retrofit, at least as far as having it hooked up goes, as I am unsure whether I want to build or buy interface.

According to calculations from specs, it seems that a mendocino celeron would want upwards of 8 Amps out of the 5 gvolts with assumed 70% conversion loss, whereas the coppermine 700 CC0 stepping would want a mere 5. So 25W for that, 10W for chipset, 5W each of 3 drives... about 50W of heat I need to dump. I hope a 60mm fan pushing and the PSU pulling will do that, because that's about all there is room for. Back panel I will have PSU out one side, i/o strip sawn in half and stacked in the middle, 60mm fan the other side.

Floppy barely fits alongside the PSU and might obstruct fan slightly, which I think I can get away with for 2 reasons, i) it's sucking and fans tend to suck from the middle and blow out the tips, kinda work half in centrifugal mode. So flow restriction is probably less than the percent of area covered on outer parts of fan. ii) Only running PSU at about a quarter capacity it seems so it should cope. Hope the PSU will start though, floppy, laptop drives only seem to be pulling on 5v, as it seems the board will be, so barely anything on 12, and I've got several ATX 2.0 where I need an old HDD plugged in to draw an amp on 12V so they'll fire up when I'm using mainly 5V. Didn't check this one yet.

Might be wanting to hunt through my entire lot of floppies for the shortest one. Know I had one or two that were nearly square. Winner at the moment is the ALPS faceless horror. This ain't all bad, because it will fit right to the top of the front panel and then have slot and buttonhole cut out. Whereas drive with faceplate would have to sit 5mm lower, which gets in the way more inside. Lot to get on front panel too, power and reset buttons, blinkenlights, front USB, front audio (and game probably) and possibly laptop speakers. I have an urge to have built in basic noise throwers. Having speakers clutter up the desk seems so unnecessary most of the time, they get in the way and fall over, you either get big speakers that don't do that, or forget the whole idea. Probably then I want a tiny audio amp and a volume knob. I might take the cones out of a stupid set of "walkman" speakers, that have triangular cases, and those stupid things are always falling all over, useless design.

CPU sink may be a bit overkill if it's only gonna be 15W and is okay up to 80c. Will look at my smaller ones. I want something that pushes air out the side though because mosfets are right there. Need a thick or copper insert base though because there's no heatspreader on a coppermine.

2017: Basement full of ancient PC stuff, starting to go through it. 2021: Still starting, heh, many setbacks. So what's this BitWrangler guy's deal ??? >>> Taming the pile, specs to target?

Reply 7 of 11, by BitWrangler

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Found a formula that says, CFM = (3.16 x Watts) / temperature delta in F so if I pick a 50 F temperature delta which is about 35C then bare minimum CFM is 3.16 coz the 50s cancel, that's STP sealevel though, so Trailer Park Boys "Worst case Ontario" would prolly need about 5CFM .. so I'll try for about 10 for a Bill Gates "ought to be enough for anyone"

My gut feels on sinks aren't well calibrated to celerons, so I looked up K6-2s and it uses/radiates less than a 350, so whereas I was thinking double the speed, double the sink, I can use one I'd feel happy using on a K6-2-350 I guess.

2017: Basement full of ancient PC stuff, starting to go through it. 2021: Still starting, heh, many setbacks. So what's this BitWrangler guy's deal ??? >>> Taming the pile, specs to target?

Reply 8 of 11, by BitWrangler

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I have 3 60mm fans to hand, two that look too weak and one that looks too loud, and they're all stickerless, so no looking up specs. ( I just want a "normal" one dammit, about 10mm, not 5, 7 or 15) So I "went shopping" in my basement for 60mms, didn't got none where I looked. However, I spot a box "misc PSU" yah, and they were very misc. So it seems I am not good at measuring things in my head that I last saw 15 years ago... the "120mm square 30mm deep" PSU is there, apart from it is 125*165*45 and puts out a whole 55W, only 7A on the 5V and the 3.3V has to come out of that too because this is AT not ATX (Board has dual power sockets in case that wasn't clear and I didn't mention it.) So that one looks like a candidate for my <486sx in a biscuit tin build. The other is a more promising 13A on 5V and 70*105*155... it miiiight be an alternative to the TFX unit. Will play around tomorrow.

Edit: Just thunk, once upon a time, I got a Volcano 7 with a thermal speed control harness, whatever happened to that??? Could use the harness to tame the fat looking 60mm which prolly pushes 30cfm at a scream. (I know I could drop the volts on it, but it's hard to know your CFM and whether it has a speck of pressure to do any real shoving once you get off the spec sheet, at least with a thermistor it would ramp up speed if it was running too slow to keep things cool)

2017: Basement full of ancient PC stuff, starting to go through it. 2021: Still starting, heh, many setbacks. So what's this BitWrangler guy's deal ??? >>> Taming the pile, specs to target?

Reply 9 of 11, by BitWrangler

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I went to bed and I was thinking "I bet ppl are wondering why I don't just plug the fan in the system fan header and let it control it"... well, several reasons, first being this one is a 2 wire fan with a molex on it... second being that this board is from the era of system/temp management "almost working some of the time" and that's not just PC Chips, took BIOS programmers, motherboard makers, and system integrators a couple of years to get it right.... third being that this is a very crowded system, can't see where the board temperature sensors are, and there's a high possibility they will get trapped in a hot zone or a cool zone with poor circulation, so will not respond in the desirable way.

2017: Basement full of ancient PC stuff, starting to go through it. 2021: Still starting, heh, many setbacks. So what's this BitWrangler guy's deal ??? >>> Taming the pile, specs to target?

Reply 10 of 11, by Caluser2000

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I'd imagine if it gets too hot Dustin will end up in the dust bin.

There's a glitch in the matrix.
A founding member of the 286 appreciation society.
Apparently 32-bit is dead and nobody likes P4s.
Of course, as always, I'm open to correction...😉

Reply 11 of 11, by BitWrangler

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Scored low on that session of 3D Tetris, I didn't think that PSU would help much and it won't. If it was all I had I could make it work with a whole new set of compromises, just a bit of a pity, as it became apparent I'm not using much of the potential of the TFX unit, so woulda been good to save that for a build that needed more of it. However, TFX supplies seem to turn up cheapish in surplus, so I could get another one later if I think of something I really wanna do with it.

Heh, there's some real clowns on classified platforms these days, just checked locally to see if anyone had any fans that I was happier about than my "stock". Some dude was selling a P4 heatsink "Brand New!" and in pic you could see the thing was caked with dust. Yup, I believe ya buddy. 🤣 Though I checked up on one of the "too slim" fans and it's supposed to do 31cfm at 4800 RPM, so that's a screamer I think, I'll put power to it, see what I think, seems fans are a "can't judge book by it's cover" thing because I saw another fan that looks like the "too fat" one, that was said to be a 2200 RPM "barely audible" one, hah.

2017: Basement full of ancient PC stuff, starting to go through it. 2021: Still starting, heh, many setbacks. So what's this BitWrangler guy's deal ??? >>> Taming the pile, specs to target?