O2 Power Supply Basics

[Elf]

Edit: With apologies, I no longer wish to have involvement with SGUG or SGI communities in general,
and have also chosen to remove all of my content. Many things have changed since I co-founded, named, and ultimately
then left SGUG. There are many good people around, to whom I apologize for frustrating by removing these things, and
also many petty people that over the years whittled down both the enjoyment as well as sense of obligation I used to
feel to anyone else regarding what was ultimately just a hobby. Unfortunately one of the latter now writes the rules
and so it is time for me to take my things and go.

This message will replace all of my previous forum posts because deleting threads that I started would have removed
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[Elf]

Edit: With apologies, I no longer wish to have involvement with SGUG or SGI communities in general,
and have also chosen to remove all of my content. Many things have changed since I co-founded, named, and ultimately
then left SGUG. There are many good people around, to whom I apologize for frustrating by removing these things, and
also many petty people that over the years whittled down both the enjoyment as well as sense of obligation I used to
feel to anyone else regarding what was ultimately just a hobby. Unfortunately one of the latter now writes the rules
and so it is time for me to take my things and go.

This message will replace all of my previous forum posts because deleting threads that I started would have removed
other peoples' posts.

 

[Jacques]

Registered just to say thank you for the power supply diagnostics on the various machines! Probably one of the most important research matters to keep these old beasties going.

 

[Elf]

Edit: With apologies, I no longer wish to have involvement with SGUG or SGI communities in general,
and have also chosen to remove all of my content. Many things have changed since I co-founded, named, and ultimately
then left SGUG. There are many good people around, to whom I apologize for frustrating by removing these things, and
also many petty people that over the years whittled down both the enjoyment as well as sense of obligation I used to
feel to anyone else regarding what was ultimately just a hobby. Unfortunately one of the latter now writes the rules
and so it is time for me to take my things and go.

This message will replace all of my previous forum posts because deleting threads that I started would have removed
other peoples' posts.

 

[Jacques]

I appreciate it, thank you!

Quick question, while my O2 PSU is open for a fan replacement ( putting the original back), I noticed a potentiometer on the daughter board labeled 'Fmin'. Does this regulate the minimum fan voltage? I only ask as my fan spins much slower in the O2 while it's connected to a dedicated 12v supply outside the psu.

 

[Jacques]

 

[Elf]

Edit: With apologies, I no longer wish to have involvement with SGUG or SGI communities in general,
and have also chosen to remove all of my content. Many things have changed since I co-founded, named, and ultimately
then left SGUG. There are many good people around, to whom I apologize for frustrating by removing these things, and
also many petty people that over the years whittled down both the enjoyment as well as sense of obligation I used to
feel to anyone else regarding what was ultimately just a hobby. Unfortunately one of the latter now writes the rules
and so it is time for me to take my things and go.

This message will replace all of my previous forum posts because deleting threads that I started would have removed
other peoples' posts.

 

[drmadison]

I'm curious if the machine will run if "only" 3.3V is supplied over that admittedly odd 3.43V line. And same with 5V over the 5.1V lines. Maybe at least on more limited systems? Would lead to a nice upgrade to a more modern PSU for these machines, assuming you can find one with suitable amps on the 3.3/5V lines. The Corsair RMx line of PSUs goes up to 25A on the 3.3V. But it seems crazy to replace a 170W PSU with something capable of 750W in the same of a slightly improved power factor...

(and LOL, the 1200W Corsair HX1200 WILL push 30A over 3.3V. But overkill much?)

 

[Elf]

Edit: With apologies, I no longer wish to have involvement with SGUG or SGI communities in general,
and have also chosen to remove all of my content. Many things have changed since I co-founded, named, and ultimately
then left SGUG. There are many good people around, to whom I apologize for frustrating by removing these things, and
also many petty people that over the years whittled down both the enjoyment as well as sense of obligation I used to
feel to anyone else regarding what was ultimately just a hobby. Unfortunately one of the latter now writes the rules
and so it is time for me to take my things and go.

This message will replace all of my previous forum posts because deleting threads that I started would have removed
other peoples' posts.

 

[Jacques]

There is a post on one of the old Nekochan threads suggesting there *is* a POT for the fan speed in the O2 PSU, I will trace it out today and report.

If I wanted to start the psu out of the machine do I just short the run line with ground? This way I should be able to test the voltage across the fan header.

 

[Jacques]

I didn't get round to tracing the POT, but I do know the fan header has 12V across the pins from power on. I was under the impression the O2 PSU had some way to regulate the voltage subject to temperature increase?

I took the opportunity to install a Cooler Master 80mm fan with 4.23mmH2O static pressure rating, it does very well keeping the innards cool. My original fan is now very noisy. The Cooler Master model is (was) often used on CPU coolers. The Arctic F8 has woeful static pressure, not really enough to draw heat out of a R10K/R12K case.

 

[Elf]

Edit: With apologies, I no longer wish to have involvement with SGUG or SGI communities in general,
and have also chosen to remove all of my content. Many things have changed since I co-founded, named, and ultimately
then left SGUG. There are many good people around, to whom I apologize for frustrating by removing these things, and
also many petty people that over the years whittled down both the enjoyment as well as sense of obligation I used to
feel to anyone else regarding what was ultimately just a hobby. Unfortunately one of the latter now writes the rules
and so it is time for me to take my things and go.

This message will replace all of my previous forum posts because deleting threads that I started would have removed
other peoples' posts.

 

[Geary morgan]

Hello, Thanks for the info. was wondering if you repair or would consider repairing O2 supplies. I have two that let the smoke out,LOL.
I do not have the means to do the repair my self. if you do not any suggestions on a possible vendor that would perform the repairs?

Thanks for your consideration

 

[Elf]

Edit: With apologies, I no longer wish to have involvement with SGUG or SGI communities in general,
and have also chosen to remove all of my content. Many things have changed since I co-founded, named, and ultimately
then left SGUG. There are many good people around, to whom I apologize for frustrating by removing these things, and
also many petty people that over the years whittled down both the enjoyment as well as sense of obligation I used to
feel to anyone else regarding what was ultimately just a hobby. Unfortunately one of the latter now writes the rules
and so it is time for me to take my things and go.

This message will replace all of my previous forum posts because deleting threads that I started would have removed
other peoples' posts.

 

[vvuk]

You may want to reach out to @weblacky -- I think he's done some of these types of repairs and may be willing to do them as a service?

 

[weblacky]

Yo, I plan to do O2 (I have two of them after all)..but I've not gotten to O2 PSUs yet. Still finishing Indy Nidec and Tezro PSU...then I need to move to Octane!. However I KNOW for a fact that Herb @ http://retrotechnology.com/herbs_stuff/mailto.html has several of them and will likely give you a very good price! Please contact him, I've purchased a few things from him before and plan on purchasing several dead PSUs from him for refurb. He's going to give you the best price around for a tested unit on short notice.

That should get you going for now. Hold on to your broken O2 PSU, I may do a call to buy them. I do have one extra O2 PSU but it's 13 years old, untested, and it's going to be the unit I inspect and rebuild first, so I don't have any O2 PSU to sell at this time. Hopefully in the future, once I've gone through all the station PSUs (or major ones) I'll have rebuilt inventory to sell consistently...it's still too early (apologizes, life happens and this doesn't really make any money as you cannot live off selling SGI PSUs).

I'll keep the groups updated. Also FYI, I'm extremely close to advertising rebuilt/tested/warranty Indy Nidec supplies here in the next few weeks!

 

[Geary morgan]

Perfect! Thank you guys, I will followup with your recommendation. yes keep me posted on your PSU rebuild services when available.

big thanks all!

 

[mgtremaine]

Ugh I think I have power supply issues sadly. Was re-reading this post because it's good enough, and I might have take the PS apart to inspect it.

This poor o2 will no complete a boot, it often makes it past chime and even comes up with the monitor sometimes before just powering off. Sometimes it doesn't make past amber. I know the sensors have a few rules (Temp above 70c, Voltage below 20% max, and Fan Speed less then 80% think are the 3.) So I suspect it's voltage. (This is R5200 300mhz with 1Gb ram).

Sadness, we've had this since 2007 and the only problem has been the disintegrating plastics...

-Mike

 

[Elf]

Edit: With apologies, I no longer wish to have involvement with SGUG or SGI communities in general,
and have also chosen to remove all of my content. Many things have changed since I co-founded, named, and ultimately
then left SGUG. There are many good people around, to whom I apologize for frustrating by removing these things, and
also many petty people that over the years whittled down both the enjoyment as well as sense of obligation I used to
feel to anyone else regarding what was ultimately just a hobby. Unfortunately one of the latter now writes the rules
and so it is time for me to take my things and go.

This message will replace all of my previous forum posts because deleting threads that I started would have removed
other peoples' posts.

 

[mgtremaine]

Somewhat expected unfortunately, they are all getting to that age! You should be able to test the voltage of the supply outside of the unit (ideally with a load). And as usual, capacitors are often the first thing to think about replacing on things this old, especially before something else goes!

I agree, I was thinking about this late last night. I don't have a scope but I do have fairly good multimeter. So I guess I'll take it apart and try figure out if this is with in my abilities. Not sure how to put a load on it though. (Otherwise I think I'll reach out to Ian.)

-Mike