Questions about small HTPC with custom case

grahamf

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Jan 9, 2013
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Last year I built a HTPC using a hec 7k09bba case.

it was nice, but now I want to go smaller. But still full featured, at least to the extent that it can do basic gaming.
Unfortunately no such case exists, so I have to make my own. I intend to get an acrylic case lasercut from Ponoko, but first I need to finalize the design. there's three styles I'm currently looking at.

Case 1: graphics card with TFX PSU
This case is designed to hold a low profile video card, and a proper TFX PSU I've found a 7750 GPU and a 350W PSU that work.
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The big white thing represents the general dimensions of the Phanteks fan and heatsink I will be using. All drives will be located underneath the motherboard or gpu, as shown.

Overall dimensions (internal): 2.5" tall, 13.3" wide, 8.2" deep

Components:
Seasonic 350W TFX12V modular PSU
Intel H77 Mini ITX Motherboard
Phanteks PH-TC90LS 45nm tall UFB CPU Cooler
2x4GB Samsung 30nm low-profile DDR3 1600 RAM
2x2TB WD Green 2.5" SATA II drives
Kingston SSDNow V+200 2.5" 240GB SATA III SSD
Intel Core i7-3770
HIS iCooler Radeon HD 7750 1GB 128-bit Video Card
Ideally a slim slot-loading Bluray drive


Case 2: PicoPSU with IGP only (wide version)
With Haswell around the corner, I figure I could possibly do away with discrete graphics and just use integrated graphics, which I estimate (using vague numbers) to be between the Nvidia 640 and AMD 7750 in performance. This won't compete with high end systems, but it should be able to hold it's own for HTPC and light gaming use.

overall dimensions (internal): 2.16" tall, 12.8" wide, 6.97" deep. to be honest I don't think the size difference is worth it, unless the system would never be upgraded to use a GPU or you absolutely need a 3.5" drive. It would, however, be a bit more simpler to build; especially since I'v enever built a custom case before.

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the big white block is the size representation of a Phanteks PH-TC90LS
Hard drives will be upside down to make the cables easier to access
the front 40mm fan is simply to ensure the entire case gets airflow, because the cpu fan will pull air from a large vent directly over top it, then push it out through the right side and the back via the left side.
the bulk of the cables can be stuffed under the optical drive, and the only four cables passing in front of the small fan are a power cable (which gets splitted) and three sata cables. I could take out the 3.5" drive and use two 2.5" drives (SSD/HDD), which would leave room for a wireless NIC. But I doubt I'd want to do that.

This mostly depends on haswell. I could possibly do this with Ivy Bridge, but I don't think Intel HD 4000 is good enough.

Minibox 200W picoPSU
Intel i7-3770
Kingston 240GB SSDNow V+200
Phanteks PH-TC90LS fan + heatsink
WD Green 2TB 2.5" (15mm tall)
Intel H77 Mini ITX Mobo
2x Samsung 4GB DDR3 ram

Case 3: PicoPSU with IGP only (narrow version)

I tried moving the drives below the motherboard, and this is what i got:

Dimensions (internal): 2.9" tall, 7.2" wide, 7.7" deep
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supports one slim optical drive and two 2.5" drives below the motherboard (one 7mm below the ODD, the rear 2.5" can be taller, even the 14mm versions). Air get's sucked in from the top and pushed out through the sides, allowing for very good ventilation. The front fans are kind of superfluous now to think about it.

providing you use a 200W picoPSU, this system can be relatively powerful:
Intel i7-3770
Kingston 240GB SSDNow V+200
Phanteks PH-TC90LS fan + heatsink
WD Green 2TB 2.5" (15mm tall)
Intel H77 Mini ITX Mobo
2x Samsung 4GB DDR3 ram

Any thoughts about these cases?
Thanks.
 
They look well designed. You will have to post pictures if you build...

I ended up using an XBox360 as a WMC Extender because it was small and fit on the home theater shelf better...the WMC HTPC sits in by my main rig.
 

grahamf

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Jan 9, 2013
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I definitely would post pictures. I plan on using a matte black acrylic case with slatted vents.

I've pretty much decided I want to do option 2. it would be somewhat simpler to do, and I've pretty much have how the case would fit together sketched out. But I have to wait for Haswell, ot at least see if the graphics capabilities are up to snuff (which they most likely are, as my minimum is being comparable to my laptop's 620M and I believe it will be better)

For grounding, I don't know how it would be done. I'd be using a picoPSU which uses this power adaptor, and I don't know how to attach grounding to it. I was planning to attach a thin grounding wire to one screw for the odd and drives, and the four corners of the mobo, but I can't really connect it to the motherboard.
 
If you use wires with a connector on the end that will slip on the screw (like a washer that connects to a wire), you can add these to the grounding points (screw holes) on the mobo, attach them to the mounting screws of the power supply, etc....it would be a few more wires, but you could find custom wires and dress them up nicely, perhaps routing them along with the other wires in the case.

Make sure to ground all components to the power supply, and use a circuit tester to verify grounding is good on all components (including hdd, dvd, mobo, ps, and anything else in the case).

I look forward to seeing pics :)

You might want to get a copyright on the plans....and distribute them for a fee....If it looks nice...I would send a few $$$ to get a nice case!
 

grahamf

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Jan 9, 2013
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I still haven't figured out how the hell you ground a PicoPSU. it doesn't seem designed to support a ground point.

The DC adaptor does seem to use a 4-pin DIN connector, but I can't figure out if one of the pins is ground.
But there seems to be one on the socket itself, but I'm not positive:
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That being said, I'm perfectly happy if someone takes these designs and goes with it. I'd definitely buy one premade also. But the precise details such as mounting points and precise sizes I haven't planned yet. if I do make it, then yes I would sell premade cases with the basics (mounting screws, front ports, and switches) preinstalled
 

grahamf

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Jan 9, 2013
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I'm tinkering with a version that has a full sized GPU. I can't say I'm fully happy with it yet, but it supports a Micro ATX board and 1 low profile card. (using ribbon riser cables)
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Width: 17" depth: 10" height: 2.5"

I think I'd definitely do option 2, but first I'm starting to set aside some money for a project computer and I really think I should wait for haswell. I'd be using this for stuff such as Portal, and while my needs aren't too extreme HD 4000 still won't cut it.
 
Grounding should be done to the metal chassis of the power supply (typically where you mount the power supply to the case). You can remove any screw from the power supply to attach the grounding wires.

If you used a metal case, grounding would be accomplished by the case. Most cases are either all metal, or they use a metal chassis with plastic covers.
 

grahamf

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Which works for the cases that have an actual PSU, but options 2 and 3 use a PicoPSU which is nothing more that a PCB board. Like I said I think the power socket seems to have a blade connector which i assume is for grounding, but I'm not positive.
 
The PCB board should have mounting screws that ground the PCB board. That should provide you with the grounding needed.

Standard wiring methods use the black wires for ground, looking at your connector, it appears the socket might have a ground on it...but that would be speculation without disassembling the connector.
 

grahamf

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The only mount point for the PicoPSU is the 24-pin motherboard socket, so it doesn't get grounded that way. Honestly, I'd have to take a look at it in person.
 
I just Googled the PSU - interesting - it should be grounded simply by plugging it into the motherboard. Since the real power conversion (120VAC - 12VDC) happens with an external power adapter, most of the heat generated would happen outside the case. You wouldn't need to have any additional grounding to the power supply.

since the power feeding the HDD, DVD, etc., would be through the molex/SATA power connector - no worries about grounding. I think the only possible issue could be with control panels that plug into the motherboard (i.e. external USB socket, power connectors, led for hdd/mobo, etc). Some use a ground to the mobo, some do not.

 

grahamf

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I want to put a really high end Haswell in it, and leaked slides estimate that it will have a TDP of 80W. eXtreme PSU calculator estimated I need at least 130W with a maximum of 195W (using a green sata, which should be the same as a 2.5" drive)

The PicoPSU I'm planning on using is the 160t version, which is 160W with a peak of 200W (the ac adapter only goes to 197W)

If I end up using a low voltage Haswell it won't be a problem, but otherwise I'm a little worried about overloading the PSU.

And for front ports I plan on just using these three things:
Vandal 22mm green ring switch - for power
Vandal 16mm orange dot switch - for reset and hdd activity
USB 3.0 front ports - for the wireless keyboard and mouse, unless poor reception makes me move it.
 
I personally don't like to push limits of the power supplies. I generally put my calculations together and add 25% to the top.

So at 195W peak, my suggestion would be to look at at least 250W power supply. The only reason I say this, is when you drive the power consumption to the max on a power supply, the voltage regulation can be off.

If you take the "gaming" part out of the equation, you can go a lot lower on HTPC builds. My HTPC that I use is only an Intel Dual Core (6 years old), 4GB RAM - and I can watch/record up to 3 HD programs at once without issues. I only have 1 XBox as an extender on it.

If you are a "light gamer", if you built an HTPC for TV/Video, and used an XBox for gaming, you could definitely cut wattage by using an Intel Corei3-3225 Ivy Bridge - uses 55W and has built in HD Graphics 4000...which would be plenty for HTPC (not so much with gaming)

Limit the ram to either 4GB to save a few more watts. Try using a Seagate Barracuda Green hard drive - they use 44% less power...or even go with an eSATA or USB-3 external hard drive (saves power and heat). Samsung makes DVD drives that consume <0.5W idle, and <5W when running.

You might even want to use an XBox360 for DVD's....and go with an external DVD...

A lot of options to cut down on power consumption. My HTPC uses about 240W in normal operation and about 300W peak - I have a 430W power supply to feed it...



 

grahamf

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The only way to get a 250W PSU is to go to a larger PSU, and even a Mini ITX PSU requires stretching the case more than i want to:

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If I go with a low voltage CPU it'll give me maybe 20W more to work with which should be fine. the PSU calculator estimates normal usage to being like 135W with only peak being 195W (with a 80W CPU), so it may be doable.
 


You can buy SATA to eSata cables cheap, or use USB-3 for faster access, and use external hard drives vs. internal to save a few watts as well. An external HDD would improve air flow and reduce heat within the enclosure as well...It could be hidden away behind something.

Given that this is going in a home theater setup, I would keep the DVD/BluRay internal - just for the appeal.

You have quite a few decisions to make on this :).