Hello:

Sorry for crossposting this, but I've had no answers from the more specific groups.

I'm in the process repurposing a power supply from a scrapped Sun Microsystems StorEdge D2 array which was working perfectly well when decomissioned.

It is a Japanese made 360W FDK PEX737-40, +5V/30A and +12V/23A.
Impressively well built hardware and in mint condition.

The final objective is to have a PS with solid +12 and +5 outputs which may eventually power USB charging ports and other assorted stuff needing quality power.

The plug at the back of the slide-in box/canister has 24 pins just like the typical male Molex 39-01-2240 connector for ATX MBs but with a different pinout and keying(?) and without all the usual ATX voltages, which makes sense as it is not a for a
motherboard.

Of the 24 pins, 19 have 18AWG and 5 have 24AWG cables.

With the unit plugged in and the rear switch 'on', I get these readings:

18AWG-red -> 0.00V to GND
24AWG-red -> 3.0mV to GND
18AWG-orange -> 0.00V to GND
18AWG-yellow -> 0.00V to GND
24AWG-green -> 0.00V to GND
24AWG-grey -> 0.00V to GND
24AWG-blue -> + 5.08V to GND <- PS_ON
24AWG-brown -> + 3.0mV to GND

This would make the blue cable PS_ON but the unit will not latch_on when I short it to GND and although there's no continuity between the green cable and GND, the unit does latch_on when I short blue+green.

The five +5V cables are on the same rail as they show 0.1 ohms between them, same for the three +12V cables.

The remaining red cable shows 10.2 ohms to the other +5V cables.

The yellow +12V cable shows 3.80k ohms with respect to the other +12V cables and is probably destined to one of the two redundant fans the array had.

With the unit plugged in, the rear switch 'on' and green+blue shorted, the unit latches_on and I get these readings:

18AWG-red -> + 5.11V to GND
24AWG-red -> + 5.10V to GND
18AWG-orange -> +12.29V to GND
18AWG-yellow -> +12.01V to GND
24AWG-green -> + 5.07V to GND <- GND(?)
24AWG-grey -> + 5.06V to GND <- PWR_OK
24AWG-blue -> + 5.10V to GND <- PS_ON
24AWG-brown -> + 5.10V to GND

So my guess is that the blue cable is PS_ON, the grey cable is PWR_OK and the green cable GND (?).

What I would need to know is this:

The 24AWG-red cable has no voltage when the unit is not latched_on, so it does not seem to be +5VSB: what is it for?

What would be the proper use of the brown cable?
Is it a sense cable like every other ATX PS?

Do I need to put in a dummy load (10 ohm/5w sandbar resistor) to insure stability?

I'd be grateful for any input on this.

Thanks in advance.

JHM

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On 06/06/2020 13:49, sawbona@gmx.net wrote:

Hello:

Sorry for crossposting this, but I've had no answers from the more specific groups.

I'm in the process repurposing a power supply from a scrapped Sun Microsystems StorEdge D2 array which was working perfectly well when decomissioned.

It is a Japanese made 360W FDK PEX737-40, +5V/30A and +12V/23A.
Impressively well built hardware and in mint condition.

Found blue+green mentioned in the last post here as power on.

https://www.eevblog.com/forum/chat/server-psu-pex-737-30-how-to-turn-it-on/

24AWG-red on a 10ohm resistor (trace it?) connected to the main 5v rail,
I'd guess would be a power_good indication. The Sun array might be in a redundant dual PSU configuration, and this could be just a monitoring wire.

Likewise with the brown.

I wouldn't get too hung up with checking deviations from the ATX
standard which possibly isn't valid here anyway. However, I would as an exercise check with a meter or a scope, voltage stability at low current
draws.

I'd think seriously about adding properly fuses in the output, when
attaching anything to it - or being especially careful with it. I have personally experienced burning cables (and skin!) on things less potent.

--
Adrian C

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Hello:

On Tuesday, June 9, 2020 at 9:49:51 AM UTC-3, Adrian Caspersz wrote:

Found blue+green mentioned in the last post here as power on.

That was me. 8^)
I was attempting to reach the poster who knew the solution was blue+green, hoping he'd know about the brown and red cables.

24AWG-red on a 10ohm resistor (trace it?)

No, haven't traced it but it is on the same rail as there's continuity.

I'd guess would be a power_good indication.

Wouldn't that be the grey 18AWG wire?
The front panel on the array had an amber/green status LED.
Green for 'no error condition' and amber for drive/fan/PS or temperature error.

... a redundant dual PSU configuration ...

Yes, it is very well designed: redundant PSU and Fan canisters.

... could be just a monitoring wire.

That is what I've been thinking, especially being 24AWG.
But if it is a voltage monitoring function like the 3.3V sense wires in the ATX design maybe(?) would be necessary for stablility.

... too hung up with checking deviations ...

OK.

... check with a meter or a scope, voltage stability at low current draws.

Yes, I have to set up a test rig once I get everything mounted.
But no scope, just a mid-quality RMS meter.

... adding properly fuses in the output ...

Of course.

I still have draw up how I'll divide this all.
Probably two separate +12V posts, two separate +5V posts and two stacked USB charging plugs, everything properly fused.

I still have to decide if I'll be using 5x20mm panel fuses/holders or maybe spend a bit more and wire in polyfuses, particularly on the USBs.

Thank you very much for taking the time to answer.

Best,

JHM

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