DIY PC case

[tadka]

I’ve now have everything I need to finish this case. I think. Still haven’t decided how/where I am going to fit the the fan. But I should be able to have it all working once it’s assembled.

There is only one thing that is bugging me – the grounding. In the end I decided all components are going to be attached directly to the wood. The only contact they are going to have between each other are the cables. PSU to the motherboard, PSU to the video card, video card to the motherboard and so on. I tried googling but there are many conflicting answers and as electricity is not my thing I can’t work out what is the right answer.

Do you guys think I should run a wire between the PSU and all the screws that will be holding the motherboard and the video card attached to the side of that plywood? Or is that unnecessary? I can’t quite understand why circuits would need grounding. But like I said, electricity is not my thing. ?

[The Duke]

Many people build bespoke DIY cases and I’ve ne er heard one speak of grounding. Your psu will ground it all anyway, and I’m amiming you have a breaker box in you elecy cuboard. So all will be fine.

[Ed P]

+1 for Duke’s reply – check at Toms Hardware for more detail.

As a total diversion from the subject the biggest problems occur when parts of the mobo are properly grounded to the case but others are not – then you can get all sorts of little problems that are a real pig to sort out.(Mainly really carp sound).

[Richard]

+1 for Ed and Steve, the PSU will be grounded by the mains connection. There used to be concern about different parts not having a common earth reference point that could lead to hum and other sound issues. I never was able to confirm that this was a theoretical or real world concern.

If external components, e.g. the screen are about to send in uncontrolled mains voltages into the PC I suspect you have bigger problems than an unearthed video card! The other issue talked about with non metallic cases is EMR into or out of the PC. Has anyone ever produced a definitive paper confirming or denying this as an issue?

If you have ever run a naked mother board to test its working did you wonder how it was able to work? I have, so my answers should read Yes and No. It just worked OK.

[Dave Rice]

…ever run a naked mother board to test its working did you wonder how it was able to work?

That’s true, done that many times. usually on top of a phone book or similar.

If screwing a mobo direct to something I’d say you need some sort of “stand off” though  to avoid any potential damage to the underside. Expansion cards back plates overhang the bottom of the motherboard too.

That’s why I thought using a motherboard tray would get around all these issues – helping give correct spacing between the mobo, components and their surroundings.

[Ed P]

Probably the easiest way of fixing would be hot glue as Toms Hardware posts make clear that bolts that go right through the work can be a problem.

As a divert the biggest source of EMR used to be switched psus (a la Apple II). This was so bad that Apple was rumoured to recommend to its sales force that the Apple was sat near a Trash 80 as it totally stuffed the Trash 80’s screen. It was also probably responsible for the US bringing in EMR certifications regs.

[tadka]

Alright, I’ve just put this thing together and it’s working. Typing this on it now.

No DVD drive to keep things simple. It can always be connected temporarily if needed. The PSU and the SSDs will be held in place by some double-sided foam-tape.

All that’s left to do is to figure out how to fit a fan, power switch and some sort of mounting bracket to hang it on the wall. I’m thinking a 20cm fan and ideally a replaceable filter in front of it. Will have to do some googling to find something suitable for this purpose.

Here are some pics:

 

[tadka]

Looking for ideas to attach those mesh pieces to the board. Glue as I planned won’t work as they are twisted and wont stay flush with the case. How else can they be fastened in such a way so it won’t look horrible as this is the side that will be facing the room?

Also looking for good ideas how to hang that box on the wall easily.

[Ed P]

Make a frame work around the wire using pieces of picture framing (just looking for the rebated x-section so any rebated wood would do). Liberally hot glue the wire to the frame or staple it, then hot-glue the wooden frame in place. All this was to conceal the staples. Of course if you do not care about appearance just staple it in place.

If you have never used a staple/nail gun do try – it is amazing how quickly you can lash things together e.g. left over wood and plastic sheeting makes a great teepee for the grandchildren!

[tadka]

I like the frame idea. I’ll staple it first then see if it worth the effort putting a frame on it. Though I don’t have a staple gun, bought some U shaped staples and will try hammering them in.

[JayCeeDee]

tadka wrote:

Also looking for good ideas how to hang that box on the wall easily.

 

Try THESE – they’ll mount the box to the wall but make it easily removable if needed in the future for maintenance/upgrades!!?

[Ed P]

It is definitely worth getting a gun, they are not overly expensive and well worth the angst of trying to hammer staples without turning a thumb and finger dark blue!

My personal recommendation would be to go for a hand-gun that handles a reasonable range of staples as you will be surprised the range of jobs that can be covered. However, I am a bodger by nature so keen DIY folk may have better ideas.

[edit] I personally think u-staples are fugly by comparison with flush staples.

[Wheels-Of-Fire]

U staples are mostly used in cable tackers. Should be noted that they increased in width when the industry switched from 4 wire to 3 pair. The old ones will pinch 3 pair. Not good for ADSL.

[tadka]

finished fitting the fan and filter and put it all together but it is not working… the leds are lit but when I press the power button it just gets a little burst of energy to the fans and goes still. any ideas what I could have done wrong? it worked last time I had it all connected. I hope I have not killed it.

[Richard]

Usually this should be down to a slightly displaced part. For example a memory item not properly seated, or the processor or its fan not fully home, etc. just reseat each item piece by piece before going further.

This does assume that you have fully checked for short circuits below the board and for correct connection of e.g. the video adapter, etc., check, check and check again. Even the power connection to the board can give this sort of trouble if it is not fully home in its connector. The all too usual and understandable reaction is ‘Panic, I’ve broken it.’ while usually you were simply tired and missed some careful step along the way.

Good luck with the fault-finding, initially with the power off!

[tadka]

I disconnected everything but ram and cpu. no change. then I removed the motherboard from the plywood and removed the screws going through it. now it is powering up with just ram and cpu. so that seems to indicate that the screws are causing the problem. but I had them in when I did the test last time. the only difference this time I had them pretty tight. any idea why the screws stop it from working? i have washers on both sides of the motherboard. those washers completely cover the round beads around the holes on the motherboard. there are two circles of those beads around each hole, whatever they are. thoughts? should I get some sort of insulating washers to go under the metal washers?

[Ed P]

My initial reaction was distortion – screwing up tight distorted something and causes a moving part to foul something. e.g. a fan gets fouled then blows a soft fuse. The other possibility is the screws are too long and are shorting/grounding something when tightened.

[tadka]

can’t be distortion, it’s all lined up perfectly with perfect spacing. can’t short the screws either, it’s just plywood. when I say tight I mean the washer and nut on both sides of the hole sandwiching the circuit board. I’m ordering some fibre washers for insulation and I won’t tighten the nuts as much. but until then I’ll try running it with the case on its side and the motherboard not attached at all.

[tadka]

It’s working for now. The motherboard is just laying flat in the case not attached at all. The fibre washers should be delivered tomorrow by Amazon. I just hope they are not conductive.

[Ed P]

Are you certain that the mobo cannot be distorted when screws are tightened? It need not be fans that are getting jammed but it could be you are just partially unseating push-in connectors and causing bad contacts.

[Author]

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