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JDW

Modern PSU for the SE/30

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@ants sounds good. I may try the same. I have (I think) the exact same situation as you - my stock Sony PSU works fine with my SE/30 running just Ethernet or just Daystar - but as soon as I try running both I get a voltage drop (4.8v roughly ... by the way my 12v disk rail is running 12.6) and random freezes or failure to boot. 

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11 hours ago, Crutch said:

as soon as I try running both I get a voltage drop

Thanks for sharing this, it's good to know I'm not the only one with this issue!

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Taking a look at the picoPSU again, I don’t know much about power supplies but the manual http://resources.mini-box.com/online/PWR-PICOPSU-160-XT/PWR-PICOPSU-160-XT-manual.pdf lists the “peak load” on the -12V rail as 0.1A. However Guide to the Macintosh Family Hardware, Second Edition p. 259 lists the peak load on the -12V rail as 0.5A. This seems like an important shortcoming - or am I missing something?

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Stock SE/30 PSU Specs:

 

+5v = 6.0A

+12Vsweep = 1.25A

+12Vdisk = 2.1A

-12V = 0.5A

 

Any replacement PSU should have the same or larger current supply capability.  Err on the side of LARGER.

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Thanks I thought so. Guide to the Macintosh Family Hardware, Second Edition p. 259 has those same numbers, but adds a footnote that peak load on the 12V disk rail may actually reach 4.0A for up to 15 seconds. 

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1 hour ago, Crutch said:

...peak load on the 12V disk rail may actually reach 4.0A for up to 15 seconds. 

All the more reason to go with the SEASONIC SSP-250SUB...


Image%202018-08-10%20at%201.01.46%20PM.p

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I wanted to thank all of you on this thread for the really useful discussion, especially @superjer2000 for the awesome step-by-step detail and photos!

 

My problem was a creaky PSU that would power the unadorned SE/30 (albeit with lower-than-rated voltages), but intermittently crash as soon as I added any upgraded kit.  Thanks to your advice I picked up the Seasonic SSP-250SUB and installed it in my legacy Apple PSU chassis.  The steps I followed were very much in line with @superjer2000's instructions, but a few details here in case useful for anyone else trying this:

 

1.  Open and gut the Apple PSU.  Pound down the standoff sort of sticking up in the middle.  Leave the bottom plastic sheet in place.

2.  Open the Seasonic PSU.  I had to chip away a few dabs of epoxy (?) to disconnect the clips, but then it just unscrews neatly from the base.  It's a nice modular PSU with no disassembly required.  The Seasonic plug assembly is held in place with three little tabs; it can be pushed right out of the chassis if you manage to squeeze all the tabs at the same time.  I did this, removed the Apple plug assembly in the same way, and inserted the Seasonic plug into the Apple chassis.  (I left the original Apple switch in place.)

3.  Drill appropriately-spaced holes for motherboard standoffs in the Apple chassis and screw the Seasonic PSU guts into place.  I left the plastic sheeting the came with the Seasonic PSU in place, but trimmed down the sides down for airflow.

4.  The tricky bit, for me, was making the wire harness to connect the Seasonic PSU to the SE/30 analog board.  I had trouble using the "staple trick" to get the pins out of the Seasonic harness and also had bad luck with a cheap pin extraction tool I found online.  Eventually I ponied up the $20 for this one https://smile.amazon.com/gp/product/B00GOIY1NE/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1 and it's amazing how much easier it made things.  I bought a 10-pin Molex power connector and just followed the diagram linked earlier in this tread to make my harness, tidying things up with cable ties.  I also poked in an extra GND wire and a green wire into the PS-ON pin on the Seasonic, which I threaded back under the PSU board to the original Apple switch.

5.  I spliced the PS-ON and extra GND wire to the original wires on one side of the Apple switch, so that turning the switch on shorts PS-ON to GND, enabling soft power on the Seasonic PSU.  I insulated the splices with heat shrink.  Then I snipped the short green grounding wire off of the discarded Apple plug and soldered it to the grounding ring on the Seasonic plug, screwing the other end back onto the Apple PSU grounding ring nearby.

 

And that's it!  Then I put everything back together and tested it with my meter before putting it back inside my Mac.  Voltages looked perfect, much stronger than my old PSU which struggled to pull 4.75V on the +5 rail.

 

One note - I am trying this without the PSU fan for now.  Seasonic specs say the fan doesn't come on below 30% utilization anyway, which I'm pretty sure will always be the case.  I also have an upgraded Nanoxia Deep Silence fan in my SE/30 which is rated at higher CFM than the original fan, and am not running any spinning HD (just SCSI2SD).  So far the PSU never seems to get more than a little warm.

 

Close-up showing the wire harness plugged into the Seasonic PSU (which is screwed into the Apple PSU chassis)--the yellow and black wires were slightly too long so just loop around slightly off the bottom edge.

 

IMG_0135.thumb.jpg.e7cea45d474724b668b98c1c986fbe90.jpg

 

Close-up of the PS-ON and GND wires going to one side of the original Apple switch (spliced + heat shrink):

 

IMG_0134.thumb.jpg.f01b7ef0d48d02cae3d718ebdc096969.jpg

 

Finished product, visible in this shot is the Seasonic plug assembly with blue capacitors (at right) and small green grounding wire soldered to the grounding tab on the Seasonic plug assembly and screwed into the chassis

 

IMG_0162.thumb.jpg.cfd503849023e8d9f681d1a211222abe.jpg

 

All closed up--looks just like an OEM part from the outside.

 

IMG_0165.thumb.jpg.e13b463197762f1a097f8c278180a9dc.jpg

 

Back home inside my SE/30 and running better than ever!

 

IMG_0179.thumb.jpg.d3fabe280045f3a4f573e998a8cdcedd.jpg

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Crutch, is this your replacement fan?

 

http://nanoxia-world.com/en/products/fans/deep-silence/240/deep-silence-60-mm-2000-u/min

 

I use a SILENX in one of my SE/30's and am curious how loud your fan is in comparison to the stock ELINA fan (which is quite loud but moves a lot of air).

 

It's taken me a lot longer than I though to finish my video on the SEASONIC upgrade.  Things keep coming up delaying the video, and then I decided to recap my analog board and run voltage measurements with that.  But the video is now coming to a close, so I intend to upload it this week and post the link here.

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@JDW yes that's the one.  It's vastly quieter than the stock fan.  My Nanoxia fan is rated 12.1 dB with 15.8 CFM at 2000 RPM.  Per spec the Silenx IXP-34-16 60mm fan moves more air but is louder at 16 dB; the Silenx IXP-34-12 moves less air (14 CFM) and is about the same loudness (12 dB).  Is this the one you have?  https://www.newegg.com/Product/Product.aspx?Item=N82E16835191005

 

 

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Yes, the Silenx IXP-34-16 is the fan I currently use:

 

 I talked a lot about in the past, but sadly many of those posts were deleted when the forum’s hard drives crashed. 

 

Specs are one thing, but putting your hand close to the fan as air moves through it is yet another.  Based on the airflow detected by my hand, it feels that the stock Elina fan moves more air than my Silenx.   I would therefore encourage you to do some before/after tests to see which one you physically “feel“ moves more air. 

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