Power Supply modding small PSUs?

Starshed

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Oct 20, 2019
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hiya, I'm a bit new and not terribly experienced, especially when it comes to electricity, which is where this comes in -

- I want to get around 400W of power in less than 20mm or so I think, and I was wondering, since all the single 400W units are at least around 25mm, could I use two smaller PSUs and have them work in tandem?

essentially I want to power a Ryzen 5 2600 on a thin-itx board with 16GB of RAM and a 1TB SSD using this PSU and then power an undervolted 5700XT using this other PSU I found on accident, and power them off of one external laptop adapter of some sort. is this possible at all?

(edit: forgot to say, could I reconfigure the cables on the 250W one so that it also has a 6 pin? the 5700XT needs an 8 pin and a 6 pin from what I can tell)
 

Thehack

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20 mm as in for the total psu height?

You do need to be clearer on how you address the size constraints for your psu.

Are you talking about dcdc size? External size? Why only one dimension?
 
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Starshed

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Oct 20, 2019
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20 mm as in for the total psu height?

You do need to be clearer on how you address the size constraints for your psu.

Are you talking about dcdc size? External size? Why only one dimension?
crap, you're right, sorry about that. I'm a bit tired today lol.

yes, what I meant was I'm trying to find a way to get a DC-DC PSU supplying 400W under that height. the other dimensions aren't too limited, it's just the height really that matters, I'm trying to fit it into a very short space that has some room to the sides. apologies for the vagueness there, and thanks for replying!

(edit: internally installed as well, oops)
 

Thehack

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crap, you're right, sorry about that. I'm a bit tired today lol.

yes, what I meant was I'm trying to find a way to get a DC-DC PSU supplying 400W under that height. the other dimensions aren't too limited, it's just the height really that matters, I'm trying to fit it into a very short space that has some room to the sides. apologies for the vagueness there, and thanks for replying!

(edit: internally installed as well, oops)

Have you determined what external acdc you will use? There aren't many 400w options.
 
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Starshed

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Oct 20, 2019
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Have you determined what external acdc you will use? There aren't many 400w options.
tbh, not yet. I did try using Newegg's PSU wattage calculator thing though and it says the wattage is just under 330, so should I go for a lower power acdc? plus I plan to undervolt, so maybe a lower power acdc will work, right?
 

Choidebu

"Banned"
Aug 16, 2017
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Choose your ac-dc first because they have different output voltages. Prominent ones are 12V and 19V. Thehack's unit (the one you linked above) accepts 12V, while laptop adaptors outputs anywhere from 15 to 21V, with 19V being most common.

If your max height is 20mm, then factoring in standoff height of 10mm, we're looking at 30mm of internal height available for your psu.

That's pretty tight. 200W, open frame, 12V output meanwells are 30mm high, 40mm with case.

You can prob use two of those, two of one2 plugin board, sync both with snyc header, and modify one to output pcie power.

@Thehack , aren't you on vacation?
 
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Starshed

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Oct 20, 2019
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Choose your ac-dc first because they have different output voltages. Prominent ones are 12V and 19V. Thehack's unit (the one you linked above) accepts 12V, while laptop adaptors outputs anywhere from 15 to 21V, with 19V being most common.

If your max height is 20mm, then factoring in standoff height of 10mm, we're looking at 30mm of internal height available for your psu.

That's pretty tight. 200W, open frame, 12V output meanwells are 30mm high, 40mm with case.

You can prob use two of those, two of one2 plugin board, sync both with snyc header, and modify one to output pcie power.

@Thehack , aren't you on vacation?
alright, well thanks for the advice! I'll try to figure it out.
 

Thehack

Spatial Philosopher
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Mar 6, 2016
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Choose your ac-dc first because they have different output voltages. Prominent ones are 12V and 19V. Thehack's unit (the one you linked above) accepts 12V, while laptop adaptors outputs anywhere from 15 to 21V, with 19V being most common.

If your max height is 20mm, then factoring in standoff height of 10mm, we're looking at 30mm of internal height available for your psu.

That's pretty tight. 200W, open frame, 12V output meanwells are 30mm high, 40mm with case.

You can prob use two of those, two of one2 plugin board, sync both with snyc header, and modify one to output pcie power.

@Thehack , aren't you on vacation?

I am on vacation; just no shipments!

He is referring to 20mm height just for the dc dc.

You do need to determine a good candidate for the external brick though.
 

Choidebu

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Aug 16, 2017
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He specifically mentioned thin-itx hence the 20-25mm requirement.

Now that I think of it, @Starshed did you do your due dilligence on thin mini itx board you're after? What thin mini itx (assuming that's what you meant by thin-itx) board needs a 24-pin power?

essentially I want to power a Ryzen 5 2600 on a thin-itx board
 
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Starshed

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Oct 20, 2019
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He specifically mentioned thin-itx hence the 20-25mm requirement.

Now that I think of it, @Starshed did you do your due dilligence on thin mini itx board you're after? What thin mini itx (assuming that's what you meant by thin-itx) board needs a 24-pin power?
ohhh wait a minute, does a CPU like that require 24 pin power..?