Concept Help with a SFF semi-passive build

Goatee

King of Cable Management
Original poster
Jun 22, 2018
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1,512
Hey guys (and gals),

I have a couple of questions I hope you guys can help with. I'm building a semi-passive <6L ultra thin (44mm)) gaming case and I have a couple of things I need some advice on.

1) Controlling a secondary PSU from thin-ITX board.

I have a thin-ITX board. Can I use powering up the motherboard to turn on a secondary power supply (HDPLEX 400W DC-ATX) which will power the GPU?

2) Case mounted screen

I have a small space in the fascia of my case (max size, 102mm x 25.5mm), is anyone aware of a small screen I could use in this space (ideally running off the motherboard LVDS header).



Thanks!
 
Last edited:

Goatee

King of Cable Management
Original poster
Jun 22, 2018
738
1,512
I am nearly finished, just got to figure out where the barrel connector is going.



I also really need to figure out how I can only switch the DC-ATX unit on when the board is drawing power.
 
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chx

Master of Cramming
May 18, 2016
547
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I also really need to figure out how I can only switch the DC-ATX unit on when the board is drawing power.

These boards typically have a plug to power a HDD and then you can just run that to an ADD2PSU? If it's SATA, SATA-Molex adaptes are plentiful.
 

aquelito

King of Cable Management
Piccolo PC
Feb 16, 2016
952
1,122
I am nearly finished, just got to figure out where the barrel connector is going.



I also really need to figure out how I can only switch the DC-ATX unit on when the board is drawing power.

Nice build :) Akasa Galileo ?

What's your CPU TDP ? I guess 35W ?
Your total consumption should be less 200W under synthetic benches.

What you can do is use a single 240W AC Adapter to power both the motherboard and HDPLEX 400W.

- You plug your AC Adapter into the motherboard DC Barrel.
- You use the 2-pin on-board power connector to ouput 19V to your HDPLEX.
- You use a small mosfet switch, connected to a fan header, to switch your HDPLEX ON/OFF.

This is what I do and it works perfectly (courtesy of @QinX).
This is by far the most compact solution for that kind of builds.

I have a Mosfet switch, one 2-pin cable and 240W brick that I do not use :)

- Mosfet switch that triggers the PS_ON function of your HDPLEX (here it's a SF450 but same principle) :


- 2-Pin on-board power connector used to output 19V to an HDPLEX

 
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Goatee

King of Cable Management
Original poster
Jun 22, 2018
738
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The case is a Galileo TU1, I wanted the Galileo TU2 but I got an amazon misprice on the T1 so I will just have to figure out what to put in the gap. Its a great case, like all the Akasa passive cases.



Build is:

Case: Akasa Galileo TU1
CPU: i7-7700T
MB: GIGABYTE MDQ17AI (PCIE 3.0 x4 and PCIE M.2 SSD support)
GPU: GTX1070 Katana
PSU: HDPLEX 400W DC-ATX
Riser: https://www.aliexpress.com/item/BTM...131.html?spm=a2g0s.9042311.0.0.42444c4dSlLa61
Brick: Dell 330W

RAM and SSD are out of my parts bin and will changed at some point.

You are spot on, power consumption is around 190w maxed out.

I really like this approach, really clean. Thanks @aquelito @QinX

- You plug your AC Adapter into the motherboard DC Barrel.
- You use the 2-pin on-board power connector to ouput 19V to your HDPLEX.
- You use a small mosfet switch, connected to a fan header, to switch your HDPLEX ON/OFF.


I can adjust my current setup to make the 2 pin cable to DC-ATX power connection, but whats the spec on the mosfet? Is there a guide on making it? I assume that just replaces the jumper I am currently using on the PS_ON.

Thats really helpful advice! Thanks again,.

@chx I think I will go with the mosfet but the ADD2PSU looks really interesting, thanks for the pointers.
 

aquelito

King of Cable Management
Piccolo PC
Feb 16, 2016
952
1,122

aquelito

King of Cable Management
Piccolo PC
Feb 16, 2016
952
1,122
I may be able to send you the one that's already built and posted above :)
Will let you know quickly if it's available.