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Alternative Power Supplies for the Fuel

Posted: Thu Oct 30, 2008 12:27 pm
by mia
This is a Fuel hardware question, therefore it belongs here.

Is it possible to "replace" the Fuel power supply with a PC one? Has anyone tried this? Mine died... you get the idea.


Thanks!

Re: Alternative Power Supplies for the Fuel

Posted: Thu Oct 30, 2008 1:16 pm
by nekonoko
You might want to look at viewtopic.php?f=3&t=10849

Obelix wrote:Thanks to anyone who gave me informations and advice!

Just a final note to let you people know the end of the story of my broken Fuel PSU. Remember that I had the +5V line gone up to +6V, causing the machine to auto-shut down. Other voltages were right.
Eventually, it was impossible to adapt a normal ATX power supply to the Fuel, not because of the differences in the connector pinout nor because of the insane current requirement for the +3.3V line, but because the environmental monitor *needs* a feedback signal from the PSU fan, a thing that no ATX power supply ever had. No signal means fan failure, which means auto shut off.
So I did what I should have done from day one – I had the PSU serviced by a competent technician.
It did cost me *a lot* of money, yet just a fraction of the 550$ that a well-known supplier of SGI spares charges for a new PSU. The culprit was a single IC that with its different sections individually controls each of the four voltages.
The technician went lyrical about the excellent design and the build quality of the power supply – and with good reason. Once repaired, all voltages remained constant within a few millivolts, even under extremely unbalanced loads (25 Ampere from one line, zero from the others).
I put the PSU back at work and closely monitored its behaviour for the first three hours, and all voltages remained rock-steady up to the second decimal digit. The only changing figures were the speed of the fans and the temperature of the chips. Apparently, nothing was damaged by the previous over-voltage.
And (hopefully) that’s all, folks!

Re: Alternative Power Supplies for the Fuel

Posted: Sun Nov 02, 2008 1:49 am
by jade_angel
I do seem to remember reading somewhere that it's possible to jimmy-rig the environmental monitor, but I don't remember exactly how. I saw an article on it somewhere, though. If I can dredge it up again, I'll post a link.

Long story short, though, it's a pain in the butt, and might be easier to just get the PSU fixed.

Re: Alternative Power Supplies for the Fuel

Posted: Sun Jan 11, 2009 2:14 pm
by directedition
If envrionment montioring auto-shut offs are the problem, that should be fairly simple to get around. PSU fans aren't all that dissimilar to case fans (in most cases they are straight up interchangeable). It seems to me you should be able to replace the PSU fan in a generic PC PSU with a 3-pin case fan. Swap the pinouts as necessary and add an extra line from the fan's third pin-out to whichever pin the Fuel expects the monitoring output.

I know I'd like to replace the PSU with an hec Raptor500 or other quiet PSU. I know the fan in that thing is the #1 noise culprit in the Fuel. I'm just not brave enough to give it a shot.

Re: Alternative Power Supplies for the Fuel

Posted: Mon Jan 12, 2009 1:51 am
by jan-jaap
I'm afraid it goes a little beyond environmental monitoring. Remember that blue Fuel prototype I've got here? It's got old L1 firmware. I don't really care, but it was complaining about it at startup so I thought I'd fix that. Did that, and it was dead.

Hooked up an L1 serial cable, got L1 prompt (phew!), did 'pwr up' and, I kid you not, it said something along the lines of "No suitable power supply found".

I rebooted the L1 in the alternative flash bank and everything worked again. Lesson learned: there's some sort of ID in the PSU to identify it to the L1 via i2c or similar and without it you get nothing. You need a real Fuel PSU.