[weblacky]

SGI_TX: Oh Man...super sorry about your experience in all this. This was a big gamble, sorry that didn't work out. I suspect that as the caps age, they take out secondary diodes or the aging turns a few resistors high-ohm and affects PSU startup. Would need to do a complete analysis...hold on to your PSU, we may be able to help in the future.

Can you tell me the SGI P/N of your power supply again? Including Rev? Perhaps a picture of the label would be best.



RAION: How open would you guys be to an idea? Our first community funded project? Based on the PSU model P/N (go, no go) I'd be willing to pay sgi_tx via PayPal $20 total (he can keep the remainder), to have the old caps shipped to me and I'd be willing to at LEAST, document the values and proper dimensions and lead spacing (I won't have the PCB stencil layout to produce "C" labels of course...) of them to at least START a materials order for PSU work. I'd be willing to release it if people donate a small amount to help offset sgi_tx a little as a community good will? I mean, if he got the original, real, caps -- yeah we don't have the locations yet. But I can PRE-ORDER replacements and I can go into a similar model (hopefully same rev) and try it myself later, without delaying (after opening) to research, find, and order caps (I'd already have them). That info is worth something to me, I hate stopping a job to order parts. HATE IT, so if I have knowledge before hand of some parts I'd need, I'd be willing to pay for that knowledge. How about other people? Not talking much, but if we could help a $400 bill turn into less and we get info, that's not a bad deal, right? He basically removed the caps and saved them for us, analysis of the caps should provide new community info. Who's up for giving a little towards that?

I won't promise to document replacement caps for this offer, but I'd be willing to at least confirm and release the existing cap info so we know values and sizes for ordering. Later on more info can be added. We can host the cap knowledge right here on irixnet wiki? If I find positions later, we can update the online info.

Are you game? It would likely take me 2.5 hours MAX to document and find suitable replacements for myself. I'd be donating about ~30 minutes for the original dimensions and values to you guys.

Thoughts?

[sgi_tx]

Thank you very much for your kind words and for your offer. As a community, I do think we need to figure out how to get a replacement supply for our Indigo2s.

I can take pics of each individual cap and post here if that helps. I'm lucky in that, unpleasant as it was, I can afford to eat the cost I just incurred.

I would be willing to contribute toward an effort to identifying an inexpensive replacement PSU for the Indigo2. I need at least 5 or 6 already, and I'm fearful that functional PSUs I have now will soon die. As I posted in a different thread, this PSU seems to have all the right current ratings:

https://www.newegg.com/logisys-computer-...6817170019

If one of us is adept and brave enough, perhaps others could contribute to shipping this supply or something like it for them to try out. After all, Grudolf94 was able to get something working with an ATX PSU... we just don't know exactly how.

[weblacky]

I wanted the caps because size matters (diameter and width), as well as lead spacing. Given the PSUs density you DON'T want to change those properties. I'd feel safer (doing a preorder) knowing the real numbers of accurate replacements. They have to fit.

Also, I'm very un-hopeful for an ATX replacement, so I'm very forward on properly fixing the originals, as it's likely not as hard as fixing a mainboard or a graphics card from an SGI. I think ATX is too much of a mod for me as a collector.

[Raion]

Ok, I'll be willing to host such a crowdfund thing, I dunno how successful it'll be, but I'll gladly fire up a post. I'll DM you shortly.

As for my own financial contributions, I think I could match $20? Depends on how this weekend goes, but I /should/ be OK.

[weblacky]

Sgi_TX: I'll leave this decision in your court. I'm not interested in ATX conversions, as these are specialized supplies and using older tech which means they are off the shelf parts and likely more fixable. I'm willing to pay you for the caps, Raion has said he's willing to put something together with me for this effort where people can donate a little towards this.

I really want a picture of your PSU label and then likely I have that model...so I'd like the caps, so I can research ordering high-quality replacements and breaking one of mine open and doing the work sooner rather than later. I'm willing to post to the community to get new Info on PSU rebuilds (that's my personal goal for my entire collection).

Let us know how you feel and if you'd like to proceed, do none of it, or modify my proposal. It's your property so it's your decision. You'd be doing me a huge favor by allow me access to those caps so I'll just state that outright (this isn't charity for me), I have three indigo2s that boot right now but I have 2 PSUs (that have been cleaned) that I bought from a user that need repair NOW, plus I have other models of SGI PSUs to research. I see the demand for PSU fixing on Indigo2, this provides a step in that direction.

Please let us know what you feel like.

[Raion]

IF we are going to do a PSU retrofit, industrial PSUs are more modular than ATX ones and easier to work with. However, I agree with weblacky here; it's probably unwise to replace with ATX - as much as that's common in PC compatible and some Amiga communities, it's a risk. You're taking something designed to operate in modern design specs and applying it to an ancient computer.

[weblacky]

I agree on the industrial PSU front, you can at least FIND specialize power requirements for uncommon voltages , better diagrams, and general screw terminal interfaces for making your own wiring harness on those. You can also get "medical grade" PSUs that give you more predictable lifespans and power filtering. I know they also have their own size standards. That being said, I assume once someone takes the time to trace out all the feedback from the SGI mainboards, someone will produce a simple dummy interface that can turn off an alternate PSU and just lie to the SGI about raising or lowering voltage levels based on load.

It was found that for some reason, Indigo2 and others do this, unknown if it was for telling the PSU about "upcoming" loads or what, but some PSU feedback was also coupled into the mainboard for increasing or decreasing voltages. Although current documentation shows this has no real effect (as it shouldn't on a real SMPS) and may have been for a reason that was later mitigated or cancelled?

I think many people have proven that (outside Fuel/Tezro Fan controls in the PSU FAN to L1?), most SGIs start right up when given the right power on the right lines. On a super technical level, the only thing I'm unaware of is the shutdown mechanism. That's hasn't been explained for most models and therefore, I believe, represents the LAST frontier to PSU experimentation on SGIs.

[Trippynet]

I'm willing to chip in a bit to help here. My Indigo2 hasn't been used much lately as both PSUs I have for it are flaky and the system won't run for more than about 45 minutes before it trips and powers down. I had one of the PSUs re-capped, plus a couple of other components were changed that were apparently not providing the correct readings, however it didn't help.

On the plus side mind you, the firm in question did fully refund me after admitting defeat with the PSU, so I did end up with a re-capped PSU for free (albeit, one that is still flaky).

To be honest, I'm torn between the plan of trying to overhaul original PSUs, or trying to get a specialised and industrial replacement...

[Raion]

What's the update here SGI_TX? Have you made a decision yet?

Some food for thought - the I2 does apparently have dynamic power regulation on its 5V rail, and that signal cannot be replicated on a mainstream ATX. This sort of regulation is also true on the Octane.