[Raion]

Dallas chips are still manufactured. I'm just gonna stockpile them eventually.

[Trippynet]

Depends which ones. Last time I checked, the DS1742W-120+ that my Fuel uses has been discontinued. I bought a spare before stocks ran out. Not sure if there is a compatible alternative that is still in production?

[jan-jaap]

Depends which ones. Last time I checked, the DS1742W-120+ that my Fuel uses has been discontinued. I bought a spare before stocks ran out. Not sure if there is a compatible alternative that is still in production?

Older types used in the Indy / Indigo2 / Onyx have also long been discontinued.

I'm against components with builtin expiry date on principle, but the ultimate insult with these Dallas chips is that by the time they run out of battery and you want to replace them they have discontinued the product series. :@

[Titox]

There are alternatives built for Dallas chips, mainly for Atari Falcon systems, so there is a possibility of build a new sustitute for the models used in sgi.

https://www.exxoshost.co.uk/forum/viewto...?f=10&t=37

[jan-jaap]

There are alternatives built for Dallas chips, mainly for Atari Falcon systems, so there is a possibility of build a new sustitute for the models used in sgi.

https://www.exxoshost.co.uk/forum/viewto...?f=10&t=37

The Dallas modules contain the RTC chip, a battery and a crystal. Sometimes (but not always) the RTC chip was also sold separately.

In the case of the Falcon, it seems the RTC chip is still available, so a drop-in replacement can be manufactured. I've considered something like this for SGI systems, but (1) there are many different types of Dallas modules used in SGI systems over the years, (2) not all of them used RTC chips where the chip was available separately as well, and (3) by the time the integrated module went EOL, they retired the RTC chip as well.

Bummer.

I dislike components with a builtin expiry date, and buying NOS Dallas chips is only postponing the problem, not fixing it. I'm not a huge fan of the Dremel either, but lacking a suitable replacement part it's a nifty hack to get a system back up and running.

[sgi-enthusiast]

Hi all,
Just to pick up on this thread regarding RTC chips, I have recently had the chip fail in my Tezro. I have sourced a replacement (DS1742W-120) and are wondering if it's as simple as a straight change-over of the chip or a particular procedure is required.
Can anyone assist?
Regards, Andrew

[weblacky]

sgi-enthusiast : I don't think there is a procedure to do a NVRAM backup/restore or anything for SGIs. Normally the new RTC is blank and the system will notice that and update it. You have may have to reset the date/time as well (not sure with a system that has a L1). But it will be evident if so.

Since I own two Tezros (one not working quite right, I just re-remembered through email searching...wow bad memory), i just went out and bought new DS1742W-120 RTCs (pack of 5 NIB on eBay, we'll see...I just made the purchase so I don't have them yet). Was able to get some price reduction with "best offer", but still $15.50 a piece. I'll likely drill the old ones but need new ones because no one has ever posted the correct drilling positions for newer RTC models, so you'll need to destroy one looking at it to save the rest :-)

I also broke down and bought out the last of the Octane/O2 GW-1687-5 Dallas DS1687-5 Maintainable Replacement modules they had (wasn't enough for all my systems...but nearly) on Tindie and bought 20 units of DS1780E ICs (off tape reel, cheaper then digikey) for future Fuels I encounter. Better get the chips while I can and have the funds. Likely won't touch them for awhile, but I'll be glad I got them when I need them.

Since Snaphats are still available, I'll not bother until I need one (or at least until I do a MAJOR PCB rebuild on my Tezro...then I might just reset everything for awhile).

Agreed with Jan-Jaap: This built-in lithium battery BS should have been OUTLAWED 20 years ago!

It should be illegal to develop a product that fully encloses a perishable battery except for weapons and marine applications.

[chulofiasco]

check these out:  GW-1687-5

his work is super clean..

[sgi-enthusiast]

Hi weblacky and thanks for the response.
I tried swapping out the chip today and even though I get the green light on the main board suggesting it passes basic energized tests, I notice that the L1 display is blank. Normally it says "L1 running" with the spinning pipe but nothing with this new chip in place. Also, the power button has no effect when prressed.
I removed it and put the original one back in and the L1 display works normally as does power up but with the wrong date of course.
I'm thinking is there more to this than just replacing the chip i.e. some procedure to activate it or did I get screwed by an ebay seller sending me a dud chip?
Cheers, Andrew

[weblacky]

Hmmm...well the Tezro has two small batteries. One in the RTC and another "snaphat" on the IO9 (yellow boxy thing). When you say the RTC failed, what symptoms lead you to that conclusion? Irix date/time is backed by lithium snaphat (apparently, see post link below), RTC chip controls L1 NVRAM and Time/Date.

Since the L1 was running, I'd have hooked a serial console to it and see what it said, my only thought is a mis-install? I own two Tezros, but never replaced the RTCs, I've only done it in older machines (like the Indigo2) and I've had this issue (not working) when I didn't plug the chip in correctly (orientation or missing rear/front rows of pins). If the unit boots and works with your old RTC chip, then I'd expect something else...if you really had a bad RTC battery...the old RTC chip would have corrupted/wiped the moment you removed it from the Tezro? Unless it has enough internal voltage to keep the NVRAM info?

How long did you let the "new chip" run for? Just curious if things weren't too hasty at the time?

Refer to this post for my info: https://forums.irixnet.org/thread-31-post-1158.html

More info would be good, please prepare to hook to L1 serial to get the real picture.

---

OK, seems this is big deal..but you may not even HAVE a dead RTC...so if you're issues was just date/time. Get a "bigger" snaphat from like Digikey using the previous posted thread link. That will fix your date/time issue on Irix. Seem the RTC stores the system SSN (serial number) and only people with Fuels have documented it. Seems if you insert a blank RTC, you'll need to interact with the L1 to reflash the RTC.

For the Fuel, they claim there is an L1 command called: eeprom Fuel write default

It's possible that Tezro (if you say "help eeprom") in the L1 has a similar command. On older machines, a Checksum occurs in the RTC NVRAM and when that fails, a default write occurs to clear the RTC. I'm shocked this doesn't happen. So I'd say, if you really have a bad RTC, you'll be the first to document what the help menu says. If that command is around, I guess that's the one that write a blank NVRAM + SSN setup to the RTC chip (since it's for the L1 only anyway).

Seems this really hasn't been tackled on Tezro. See here: https://web.archive.org/web/201603190719...2#p7346146

This came as news to me...also worried me (as I own two of these things). So, if you still experience issues, after replacing your snaphat (L1 issues I guess), then please slowly take use through the L1 help and see if that works? My guess is, because you reinstalled your old one successfully...your RTC hasn't failed.

Sorry for the confusion, the last two SGI systems were based on brick designs and have oddities we are not too familiar with, this being one of them.

Hopefully, no harm no foul,