[weblacky]

I don't think it's different, it appears to be the TSOC package (shown on the first page...just the entire side to blown out..see the test pads on both sides?  Three connections on two sides, but the top side is complete not-connected internally, so they are used only for mounting the SMD package into the board.

Problem is...overvoltage happened on the DATA/PWR one-wire line...that's really bad...because there is a controller somewhere that READS that write-once (paged memory) EPROM...which means the entire one-wire bus (even if it's just a single microprocessor to one slave DS2505 device that blew, experienced way too much voltage on the entire comm bus...so that "controlling" microprocessor is also likely damaged!

These EPROMs are still sold and are a page at a time write-once programmable storage.  They are not meant to be altered after writing, but you can write sections at a time and unused sections can later be written to at a later date.  Programming requires a pretty common EPROM programmer but uses higher voltage to write so likely they didn't allow field-programmable functionality.  So it's highly likely to be a "program then solder to the board" affair.

It's likely this was used to, at least, store the serial/device information of the device that is read during device initialization to identify it to the Octane by part number and such.  It MAY have stored firmware for its controller, master, microprocessor.  We would have to get a duplicate unit and read what's on it to know that.

Somehow something failed in short in a bad way...not in an "open" good-way.  Too much voltage went through something into the one-wire comm bus that EPROM uses and damaged everything attached!

I'd say that's likely NOT repairable...because the damaged MUST extend to the system on the card that constitutes its "brain" that read those values and also maanages/responds/execute operation requested from the Octane over the XIO bus...that "brain" MUST have custom firmware...so even if replaced would be missing its custom programming by SGI during factory production. 

Without finding that component we don't know whether the firmware is programmed directly into storage inside the controller or the controller automatically starts and reads it firmware from an external chip, that COULD be cloned. 

There is a equal chance that such hardware of this vintage may use external storage and so it may be possible to replace all the necessary chips after cloning all info from a duplicate board and simply copy the EPROMS (assuming no "protection" is in place to keep us from reading them) to new units and then solder them to this board... However it was becoming more common at this time in history for microprocessors to have their own internal storage that could be protected against espionage that would've been specially program during production and then sealed off. If that's the case then unless you're going to steal a working brain from a duplicate graphics board there MAY be no way to fix this board. Because you could replace the chip but without the custom programming, it has no brain.

You would have to catalog every major semiconductor on that entire card, searching for what could be the brain and also what's damaged or connected to that bus. All chips connected on it or through it would have to likely be replaced. Any chip that carries internally programmed memory, that is under protection and cannot be read out, stops the entire process of cloning a working unit's firmware onto new chips for replacement for this card.

It's now just connectors and basic parts only...it's very likely brain dead.

I'll also say that while every part has value, this is IMPACT not VPro, so there's likely no value in doing it other than someone's educational value or experimentation. If this were a V8 or a V10... It would be worth the attempt given the value. But the older graphics cards just aren't so valuable that it's worth much. As a board and its connectors it has some value, not zero, but unfortunately since power snuck into the internals past all the protection and blew the low-voltage internal comm line, you'd have to investigate the extent of the damage. Then you'd be able to act but it would be quite a bit of research for a low value graphics card.

It would however be valuable to know how the heck that much power got in there! Because what it might mean is that there's some component on there, whether that's a capacitor or something, that really should be refreshed/replaced before this happens to other cards of the same design.  Obviously this is a design flaw, most of the time you would engineer multiple safeguards to blow out as fusible links that would keep this much power from getting to an internal low-voltage communication line. So that sets a precedent that doesn't sound very appealing for long-term collectors.

I'm guessing U8 is a memory chip. It seems like EPROM chip, though it looks different than the on google shows:
https://www.analog.com/media/en/technica...DS2505.pdf

This is interesting, but over my head.
Do chips like these get initialized when the board comes online or was it programmed at the factory, and not something one can just easily replace?