Modern PSU for the SE/30

[JDW]

There's only one benefit i can think of - it's fanless...

As I said in my earlier post, the Seasonic documentation says it can run fanless if the LOAD is 30% of max.  You gentlemen who use the SEASONIC, can you please confirm this in your SE/30 use cases?  Please explain how that feature works.  Does the fan simply not spin at all when the actual LOAD is only 30% or less than a 100% LOAD?  Or must you connect a wire to get that feature to work?  How does it work?

Thanks.

 

[superjer2000]

There's only one benefit i can think of - it's fanless. I've just replaced the fan in my SE/30 with a nice quiet Noctua one, and it'd be a shame to add another fan for the PSU.

I'm not adverse to keeping the brick outside of the Mac - but I'll assess once it arrives.

Well given how awesome your internal wifi build thread was I'm just excited to read about whatever you do with this PSU. 

 

[Von]

My Seasonic unit that @superjer2000 has arrived and I fiddled with this and got it working today. 

I started by pulling wires from ATX connector using the staple trick to get the molex pin out:



All pins were removed with this method so I didn't need to crimp any new pins.

After getting the dead PSU out, the Seasonic would fit just fine inside the PSU chassis so I tried to figure out how to secure it. First I tried using screws from the Seasonic through existing holes in the chassis:



I tired to do this project without any new holes in the chassis and this didn't allow me to power it the way I planned by bringing a standard 3-prong power cable inside from the switch:



The existing holes were either too far forward for the power cord to do a 180 towards the switch or too far back such that it wouldn't allow the chassis to close.

I then resorted to zip ties to hold Seasonic in place...





I think I went the same route as superjer2000 with all of the wires: 

Normally, this style of power supply is operated by soft-power.  A momentary switch on the computer case issues a latch which the motherboard places on the PS-ON pin of the power supply.  Our SE/30 does not have the circuitry to do this, so we need to force the power supply to be on when the switch is on.  We do this by shorting the PS-ON pin (green wire) to GND (black wire).  After placing the small shunt, the power supply will turn on fully as soon as the power switch is flipped on. 

To handle PS-ON, I just grounded this on on of the unused ground wires coming off of the PSU (black plug on the right above). The stock SE/30 plug is bottom left, the longer +12v yellow with extra wraps is used for sweep...it came from that 4-pin (2 YW & 2 BK) plug that I left attached. These yellow wires are joined at the connection to the PSU.  Same goes for the yellow wire to the hard drive plug...it is shared with the other +12v.

So here is a look at the wire loom packed into the chassis:



To make the connection to the power cord, I went to the local Vetco and got some of these doodads:



The stock connection from the switch to the original PSU uses a 4-pin with of this type with only 2 outer pins.  I soldered power cords hot and neutral to this and then a round termination for ground:



I closed up the chassis and tested voltages and all seemed good.  

Both +12v were at 12.03

Both + 5v were at 5.13

The -12v was 11.98 which seemed close enough...

With this I installed it in the case and promptly attached the PSU plug to the motherboard plug.  After getting that set straight I crossed my fingers, made a few offerings to Ullr, I turned the power on.  I got happy chime then chime of death.  I scratched my head after I walked away for a bit and then realized last I was using this motherboard I was testing RAM and it had bonked because I had 4 1MBs in front and 4 16MBs in back.  I then swapped out to my SE/30 board that will soon be recapped and tried it. While it gave no chime, it did boot...yay!  I then realized the cursor would not move. Ooops...I forgot to plug in the ADB.  After trying again, the machine booted and worked as expected.  I will play around with this more tomorrow after some sleep.

 

[JDW]

The -12v was 11.98 which seemed close enough...

If you meant to say "-11.98v" then, yes, that would be close enough.

Thank you for the excellent photos and explanation.  I'm about to pull the trigger and buy two of those SEASONIC PSU's myself.

 

[Von]

If you meant to say "-11.98v" then, yes, that would be close enough.

Thank you for the excellent photos and explanation.  I'm about to pull the trigger and buy two of those SEASONIC PSU's myself.

Indeed, I did mean -11.98. Seems I can't edit a post after someone has submitted a replay so my error will live on...

 

[JDW]

My Seasonic SSP-250SUB PSU arrived today with absolutely no documentation.  Does anyone have a link to a wiring diagram of the 26-pin Molex connector?

I'm trying to figure out which wire is what.

 

[JDW]

As per the post by joethezombie, I can confirm that you get no output voltage on any wire of the Seasonic SSP-250SUB PSU until you connect the GREEN wire to GROUND (connect GREEN to any BLACK wire).

I of course can measure the voltages of each of the wires in the PSU's wire harness to know their voltage level, but I still would like to know what the output schematic is.  I want to see which voltage output is isolated, and so on.  Do any of you have that info?  I can't find it by Googling it.  But maybe some of you have found something I've overlooked.

Thanks.

 

[superjer2000]

My Seasonic SSP-250SUB PSU arrived today with absolutely no documentation.  Does anyone have a link to a wiring diagram of the 26-pin Molex connector?

I'm trying to figure out which wire is what.

All of the colours follow the ATX standards. Also, if you look at the connector that came with the supply, look at the ATX motherboard ends (which are searchable via google) and you can just follow the lines back to the plug on the PSU. 

Also so if you look at the picture of the cable I made on page 3 of this thread it might help also. I used blue for -12 red for +5 and yellow for +12

I actually just bought two more of these as Newegg is clearing them out for US$32 so I can retrofit my SEs now. 

 

[JDW]

Consider the multitude of red wires coming from that harness.  How do you know which red wire is which in terms of ISOLATION?  Consider the I/O description:

Which wire corresponds to +12V1 versus +12V2, which I assume made distinct in the above chart because they are isolated.  The same is true of +5V and +5Vsb in the above.

 

[superjer2000]

Consider the multitude of red wires coming from that harness.  How do you know which red wire is which in terms of ISOLATION?  Consider the I/O description:



Which wire corresponds to +12V1 versus +12V2, which I assume made distinct in the above chart because they are isolated.  The same is true of +5V and +5Vsb in the above.

Any of the 5v red wires will be fine. The 5vsb is for standby and is a purple,wire you won't use. None of the red wires are isolated. 

Im not sure if there is any 12v isolation either but I took one 12v source from the main ATX connector and the other one from the 4 pin processor connector. Here's an interesting read on multiple 12v rails:

http://www.tomshardware.com/forum/306437-28-single-rail-multiple-rails-eternal-question-answered

 

[Von]

I actually just bought two more of these as Newegg is clearing them out for US$32 so I can retrofit my SEs now. 

My 2nd is arriving tomorrow and will be used in my IIsi.

 

[JDW]

My 2nd is arriving tomorrow and will be used in my IIsi.

Newegg won't ship to me in Japan, so I had to buy from EBAY:

https://www.ebay.com/itm/Seasonic-SSP-250SUB-250W-80-PLUS-Bronze-Flex-ATX-Power-Supply-w-Active-PFC-F0/322465486196

With shipping to Japan I paid $80.  I would have rather had 2 units, but at that price I settled with one.

 

[JDW]

By metering the output wires of my Seasonic SSP-250SUB PSU, I see the following:

• Yellow wires are all +12V, although which rail I do not know.
  
• Orange wires are all +3.3V
  
• Red wires are all +5V
  
• Purple wire is +5V (Vsb?)
  
• Gray wire is +5V (also Vsb?)
  
• Blue wire is -12V (negative with respect to Ground)
  
• Black wires are all (-) Ground.
  
• Green wire must be shorted to (-) Ground for the PSU to operate.
  

 

[JDW]

I left the Seasonic SSP-250SUB PSU connected to AC power with the Green wire Grounded and NO LOAD (because I am merely checking voltages at this stage).  After 1 hour I came back and it was very hot to the touch.  Not too hot to keep my hand on it, but uncomfortably hot.  The fan was not spinning, and no surprise because it says the fan won't spin if the load is very low (which is NO LOAD in my test case).  So it would seem the fan isn't temperature controlled, so if you leave it in a NO LOAD or very small Load situation, its internal fan will never turn on and it will get quite hot.  This is something to ponder when using it inside an SE/30.

 

[superjer2000]

I left the Seasonic SSP-250SUB PSU connected to AC power with the Green wire Grounded and NO LOAD (because I am merely checking voltages at this stage).  After 1 hour I came back and it was very hot to the touch.  Not too hot to keep my hand on it, but uncomfortably hot.  The fan was not spinning, and no surprise because it says the fan won't spin if the load is very low (which is NO LOAD in my test case).  So it would seem the fan isn't temperature controlled, so if you leave it in a NO LOAD or very small Load situation, its internal fan will never turn on and it will get quite hot.  This is something to ponder when using it inside an SE/30.

I think that's because you didn't have any load. Try hooking up a couple of hard disks.  

I ran mine in my se/30 with the case off for a few hours and then pointed my FLIR at the PSU and it was maybe 35c at the absolute hottest spot. 

 

[superjer2000]

My 2nd is arriving tomorrow and will be used in my IIsi.

Does the IIsi have the same type of soft power circuit as the IIci?  Are you building the circuit in the below thread?  I was considering using one of these for either my IIci or IIcx as at $32, it's probably cheaper than recapping those supplies  

 

[Von]

Stay tuned....I am going to be adding my questions to the thread you referenced @superjer2000

 

[JDW]

I think that's because you didn't have any load. Try hooking up a couple of hard disks.  

Yes, but not everyone will chose to run an internal HDD within their SE/30.  For example, I have my SE/30's HDD in an external Apple HDD enclosure that sits under the SE/30.  So what happens if you run your SE/30 with the HDD disconnected?  My guess is the total load would fall to such a level the internal fan of the PSU wouldn't spin, and that would heat the PSU.  Also, with your setup the way it is now (with your HDD still connected), does the PSU fan spin?

The real issue here though is how you chose to install your PSU.  You removed the stock chassis and put the PCB guts inside your SE/30's PSU chassis.  However, Von chose to keep his Seasonic PSU chassis intact and used wire-ties to mount that entire Seasonic unit inside the SE/30 PSU chassis.  If one does as Von did, the fan would be more important seeing there is less air flow around the power supply PCB if that fan isn't running.  But in your case, you removed the Seasonic chassis and remounted the fan, so even if the fan doesn't spin in your case, there is still more open air around the PSU PCB in your case, thereby (in theory) keeping in cooler.  

So I would think that whether the fan spins or not could be an issue, depending on how one chooses to mount the Seasonic -- as is with metal chassis, or like you did by removing the PCB and not using the chassis.

 

[superjer2000]

Yes, but not everyone will chose to run an internal HDD within their SE/30.  For example, I have my SE/30's HDD in an external Apple HDD enclosure that sits under the SE/30.  So what happens if you run your SE/30 with the HDD disconnected?  My guess is the total load would fall to such a level the internal fan of the PSU wouldn't spin, and that would heat the PSU.  Also, with your setup the way it is now (with your HDD still connected), does the PSU fan spin?

The real issue here though is how you chose to install your PSU.  You removed the stock chassis and put the PCB guts inside your SE/30's PSU chassis.  However, Von chose to keep his Seasonic PSU chassis intact and used wire-ties to mount that entire Seasonic unit inside the SE/30 PSU chassis.  If one does as Von did, the fan would be more important seeing there is less air flow around the power supply PCB if that fan isn't running.  But in your case, you removed the Seasonic chassis and remounted the fan, so even if the fan doesn't spin in your case, there is still more open air around the PSU PCB in your case, thereby (in theory) keeping in cooler.  

So I would think that whether the fan spins or not could be an issue, depending on how one chooses to mount the Seasonic -- as is with metal chassis, or like you did by removing the PCB and not using the chassis.

The SE/30 is the load. I meant it didn't make sense to bench test the PSU without any load and for that purpose you should have hooked up something like a hard disk.  Even a fan might be enough load.  My SE/30 has a SCSI2SD not a spinning HD and as I noted earlier in this thread, the Seasonic PSU fan still spins up. The venting isn't the issue, the lack of load likely is- or else your PSU is defective. 

 

[JDW]

The SE/30 is the load. I meant it didn't make sense to bench test the PSU without any load and for that purpose you should have hooked up something like a hard disk.  Even a fan might be enough load.  My SE/30 has a SCSI2SD not a spinning HD and as I noted earlier in this thread, the Seasonic PSU fan still spins up. The venting isn't the issue, the lack of load likely is- or else your PSU is defective. 

I connected my Seasonic PSU to a single spinning platter HDD for 1 hour and the HDD was spinning for that entire 1 hour.  The PSU fan never came on, and it was just as hot to the touch after 1 hour as my previous no-Load test.  Again, I am not surprised the fan did not turn on because the Seasonic makes it clear that it won't turn on if the Load is 30% or less of its output capacity.  Again, this seems to prove there is no temperature sensor or temperature activated fan control in the Seasonic PSU.



UPDATE: Hmmm.  Maybe it does have a temperature sensor after all.  It's pretty hot here in Japan, so I decided to switch off the A/C for a while and then watch the fan.  Sure enough, the fan started spinning.  It spins 8 seconds ON, then 8 seconds OFF, and then that cycle repeats.  The PSU is still quite warm to the touch, even with only that HDD spinning, but at least I now know the fan is working and it seems to be temperature controlled.