[weblacky]

Hi All,
   I used to be a Nekochan lurker a few (9) years ago...life got busy...now things are what they are.  I own several SGI stations and lots of dev software.  Those of you from Nekochan may remember my Tezro issue (placed too many PCI cards (filled it) and found with a Firewire card installed I had a VRM module kernel panic within 10 minutes of booting.  Replaced the VRM, no change, removed the Firewire PCI card...problem went away...that was me :-)

I've shaved down my SGI collection to the basic best: Indy R5000, O2 R5000 (@ 200Mhz but have a 300Mhz CPU somewhere...I bought it, but never installed it), an Indigo2 Hgh-Impact, and a Dual 800Mhz, dual headed, Tezro that I arranged to buy over Nekochan around 2010.

OK, now that I've introduced myself...I feel like I need to express a topic no one seems to talk about...but I was hoping to pick some brains,  Preventative maintenance of SGI Power supplies!

I've left my units unplugged for years now, I've not started them...nor really had the time right now.  But I'm worried about starting them in the future.  After all...they worked when I shut them down...but that's no guarantee for the future.

So what do people think about getting together a list or at least sharing some experiences of what actually "went" in their PSUs (all SGI models) and coming up with a list or plan to "refresh" PSUs...that haven't yet failed.  None of these PSU are new, period...we all know the PSU is the saving grace to preventing board damage due to out of spec power.  You don't want to power an out-of-spec component!  Replacing before power-on and you avoid death.

I have pretty good soldering skills (professional station and micro tips as well, but no hot air or PCB board heater) and am not afraid of removing and replacing basic through-hole components or even larger surface mount components (including ICs).  I own an ESR meter and a ring-inductance tester. 

I'm more worried about my Tezro than anything...since it's the most complex unit I own.  But I won't leave anyone out if you have valuable info to say about your PSU repair experience or the like.

Before they fail, what components should just be whole-hog replaced (due to heating, aging, duty cycle, etc..) to prevent destruction of this vintage equipment?  I understand there is the adage of "if it ain't broke, don't fix it".  But judging from stories, I'm unsure SGI designed these stations to survive a PSU component failure (that doesn't blow the fuse).  We have no support and no supply lines, so I think we should throw that adage away and instead think of something like, "put fresh gas in it".  We could just say, replace ALL caps.  OK, but what else?  All Diodes? Thoughts?

Also I realize I'm not differentiating between hot and cold PSU sides where issues change.  On hot sides it seems filtering caps, overheated diodes, and over-volted transistors seem common for consumer appliances.  But on the Cold side, you have Logic and grounding caps, perhaps just dry solder joints.    I'm looking for insights here.

Thanks for sharing any input and photos you all have!