[vvestraa]

Well, it finally happened to me.   I left poor 1x800MHz Tezro in a damp cold basement for the entirety of the COVID-19 year.  And now, when it powers up, a little bit later it complains "XIO 5V low fault limit reached" and reports low voltages. Then, thankfully, shuts down.

I pulled out some RAM, pulled out the CDROM drive and pulled out the fiber card, but the problem still remains.

I now do not know if the problem lies in the power supply, on the mainboard, or in the smaller parts like voltage regulators and V12 graphics boards.

So I have dug out my RS232 NULL MODEM cable, and a Windows laptop with a Terminal program, but what's the use. 

L1> env will report ... some voltages, and only when the XIO V12 video card stuff really starts up, will the problem show up again.

I was excited to find the FUEL guy who made a small widget that lets you connect an ATX power supply to a Fuel. 

I thought this was awesome:  https://forums.sgi.sh/index.php?threads/...power.134/

I am excited about Corsair TX750M power supplies being available on Newegg for only $120, which are probably much finer than the DPS-550BB E ever was.

These are available on eBay for $235 but even that is a lot of money:

https://www.ebay.com/itm/For-SGI-Power-S...3654975803

And am excited to have a brand new account on this "IRIX Network" BBS!

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And this is where I discover that HyperTerminal doesn't come on Windows Vista .... ...... it's only on Windows XP !

[Raion]

It's the power supply, and your Tezro shouldn't be used with an ATX adapter - it is not compatible, or even straight through. You will hear people talking about it working, but that link points out that the Tezro's voltage demand goes up and down via a connector on the board. If you omit that, it's possible you're undervolting or overvolting components running on the rails. That's potentially going to shorten component life.

Do what I did and get a NOS PSU. It's not worth running it out of spec.

[vvestraa]

So, spend the $235, and buy the power supply on eBay ?

Thank you for the reply! Perhaps I will do that.

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Raion --- where did you get your New Old Stock power supply?

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I've noticed that my Dallas DS1742W Timekeeper chip is now seventeen, eighteen years old.

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https://www.ebay.com/itm/1pcs-DS1742W-12...2866064876

This link looks really interesting... ....

https://tips.graphica.com.au/sgi-nvram/

and this one...

https://www.eevblog.com/forum/repair/rev...s-ds1742w/

[Raion]

So, spend the $235, and buy the power supply on eBay ?

Thank you for the reply!  Perhaps I will do that.

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Raion --- where did you get your New Old Stock power supply?

---

I've noticed that my Dallas DS1742W Timekeeper chip is now seventeen, eighteen years old.

=== ==== ==== ===

https://www.ebay.com/itm/1pcs-DS1742W-12...2866064876

This link looks really interesting... ....

https://tips.graphica.com.au/sgi-nvram/

and this one...

https://www.eevblog.com/forum/repair/rev...s-ds1742w/

The Israeli seller on eBay. I paid like $100 for it.

[weblacky]

So, spend the $235, and buy the power supply on eBay ?

Thank you for the reply!  Perhaps I will do that.

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Raion --- where did you get your New Old Stock power supply?

---

I've noticed that my Dallas DS1742W Timekeeper chip is now seventeen, eighteen years old.

=== ==== ==== ===

https://www.ebay.com/itm/1pcs-DS1742W-12...2866064876

This link looks really interesting... ....

https://tips.graphica.com.au/sgi-nvram/

and this one...

https://www.eevblog.com/forum/repair/rev...s-ds1742w/

Don't buy RTCs from China ebay sellers...they are pretty much all fake, we've proof.  Buy from USA sellers and expect high prices.  I recently spent $85 for five of them on eBay, from a seller in California.  I don't know if they work or are genuine, they certainly look good.  That was last auction I've seen lately from USA sellers that didn't use a fraudulent picture.  I had to buy all 5 because he sold them as a lot only, he wouldn't break them up...he was just selling all he had. I just did it, I would have rather liked to only buy 2-3 units.

I guess that means I do have "extra", but with a question mark because I didn't buy them from a known and trusted supplier.

I'm hoping we can find a way to drill the chips later on, though I may have to sacrifice the first RTC that goes dead to find out where to drill.

[vvestraa]

Weblacky, please allow me to ask this almost criminally stupid question:  Is my DS-1742W soldered onto the Tezro mainboard?  Or, could I just pull it off, push on one of your $18 ones from eBay, type something magical at my L1 prompt like "serial set A1234567" and then my Tezro would be OK again for at least five more years? 

I see a lot of talk about the MiniPRO TL866 eeprom writer, talk that scares me.

https://www.youtube.com/watch?v=FLG03f_ua5g

[Irinikus]

I really doubt that the flat Dallas chip is the source of your power problem! (Mine runs perfectly with a flat Dallas chip!)

I therefore wouldn’t recommend touching it!

The nice thing about the Tezro is the fact that replacing the SnapHat on the IO9 sorts out time keeping issues.

[Irinikus]

It may also be faulty environmental monitoring chips, like those found in the Fuel!

[weblacky]

Weblacky, please allow me to ask this almost criminally stupid question:  Is my DS-1742W soldered onto the Tezro mainboard?  Or, could I just pull it off, push on one of your $18 ones from eBay, type something magical at my L1 prompt like "serial set A1234567" and then my Tezro would be OK again for at least five more years? 

I see a lot of talk about the MiniPRO TL866 eeprom writer, talk that scares me.

https://www.youtube.com/watch?v=FLG03f_ua5g

Recent forum research has proven that the answer is yes, to the latter.  I do believe that all the RTCs have been socketed in the workstations.  Some of larger mini fridge sized SGIs do have soldered RTCs and the Iris Indigo has a solder lithium battery.  All the stations have replaceable RTCs.  

The scary part is if you don’t start with a blank (new or wiped via programmer) RTC in a Trezro. Unlike every other SGI, Tezro has issues with not wiping and totally defaulting to setting up an RTC when it has old contents on it.  Other SGIs don’t have this problem, but Tezro does and it won’t let you set serial correctly of it has old data (not from another Tezro).  If your used chip does come from another Tezro you can use the set serial command to change it. But if it’s from another device, you’ll have trouble.

It will auto setup if totally blank and sometimes you’ll need to use set serial, sometimes not.  

jwhat & khral confirmed this for us not too long ago.  If you can drill the RTC then loss of power by removing battery leads and reconnecting a new battery will also blank the RTC.  So setup for life :-).  

Now that we know people’s previous issue with used RTCs and the solution, it’s less scary.  

Yeah, it sucks the RTCs when out of production when some of them are still made! But it’s workable. If I were you I’d just watch out for a new RTC on eBay and leave what’s in your Tezro.  If it’s battery goes dead you can still operate, you’ll just need to reset L1 time at boot and if you keep default nvram setup (I do) you’d not notice it.  

A dead RTC on a SGI doesn’t prevent boot, it just resets on power loss, but if you keep things stock, you can just plug power in when you want and re-setup the time in the worse-case scenario.  

Once most SGIs start they provide power to RTC and when it’s externally powered it operates just fine, so you can still start the system.  


Just think of like an old PC where the moment you unplug it the BIOS forgets all time and settings.  That’s all that would happen on Tezro.  It would still boot.  

Unless you have some reason, it’s not a critical thing to worry about. 

We’ve never had a report here of an RTC actually going bad and failing, just the internal battery inside the RTC.  Most of the time you drill it or buy a drilled one from someone else.  But you’ll still boot.  Don’t worry yourself too much, you won’t be stuck or dead with your current RTC.

[vvestraa]

Thank you so much for helpful replies.

I am currently in mourning for my Tezro, but it is kinda stupid.  A power supply with electrolytic capacitors from 17 years ago, stashed in a damp dark basement for years, well what did I expect.

I am happy to learn about the yellow SnapHat, and the DALLAS chips, but my big problem now, I suppose, is finding an old Tezro power supply at a reasonable price, and hoping that was the problem. 

That does seem the most likely problem because now when I attach the power cord, and the Windows XP computer running HYPERTERMINAL at 38400-N-1 using a null modem cable, a terrifying thing happens: 

L1 screams "INFO:  Cannot enable VRM: 9 / INFO:  Cannot enable VRM: 10 / INFO:  Cannot enable VRM: 11"  and then, for god's sake, the L1 REBOOTS , I hear the relay go "CLICK", and I can never even get an L1 prompt.

This is sad indeed.


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I am not a power-supply-designing electronics wizard like those EEVBLOG types, though I think it would be fantastic if you could somehow hotwire a modern CORSAIR TX750M to get the job done, even if it has to reside outside the Tezro case like an unsightly metal wart.

But that's just me dreaming.  Perhaps it has died, for real.

eBay has the power supply, from China, for $235.   Ian of SGIDEPOT has one at .... ...   at a very high price.   I am just a poor hobbyist, no way can I afford

I guess my best bet now is to scour eBay continuously for a cheaper SGI P/N 060-0162-002 Rev B

or donate the Tezro to a nearby computer recycler.

Which would be FREE GEEK TWIN CITIES.

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Or set up an auction on eBay where I make it clear to buyers, the power supply has gone bad and it might be DOA but then again it might not.