[gmcenroe]

I usually keep my Indigo 2 running all the time. When the weather gets warm like in the 80s the office gets hot and my computer shuts down. It won't reboot but later if
it cools down and I unplug the power cord, plug it back in it reboots without any problems. Is there a protection circuit that shuts it down or is this a sign that the power 
supply is near its end. This has happened several times over the past few years with no permanent failure.

[weblacky]

I've not been in an Indigo2 PSU for some time. But I KNOW Indy Nidec PSU has a temperature cut-off sensor of sorts in it on the HV side, so I would assume Indigo2 PSU does as well. It's an odd two-legged IC standing up like a dual diode pack. However that does not conclusively prove your PSU isn't overheating from age. But given the vintage, yes, it likely does contain a temperature cut-off IC because I know the Indy PSUs have them.

The real question is, is the temperature protection failing and cutting off on a false positive...or are you really overheating?

[gmcenroe]

I've not been in an Indigo2 PSU for some time. But I KNOW Indy Nidec PSU has a temperature cut-off sensor of sorts in it on the HV side, so I would assume Indigo2 PSU does as well.  It's an odd two-legged IC standing up like a dual diode pack.  However that does not conclusively prove your PSU isn't overheating from age.  But given the vintage, yes, it likely does contain a temperature cut-off IC because I know the Indy PSUs have them.

The real question is, is the temperature protection failing and cutting off on a false positive...or are you really overheating?

It only powers down when the room temperature  goes above 80 F. Hitting the power on button does nothing. I have to unplug the power cord, wait until room cools down, then when I plug the power cord back in, the fan comes on and it reboots.

[CB_HK]

That definitely sounds like a thermal cut-off fuse. SGI used those pretty extensively and they act exactly as you describe--preventing a restart until the fuse cools and either closes or opens the circuit, depending on how it's designed.

Above 80 for an Indigo2 could be an issue depending on airflow, what boards are installed, and to weblacky's point, the age of the PSU. I'll say that when I run my Indigo2 my room is cooled to around 72-74 and I typically measure output exhaust at 92-95 degrees at the front fan and PSU fan. I would imagine if your system is more sensitive to heat due to age that's where the issue may lie.

Ultimately SGI made these systems to run inside cold office environments so above 80 may not be something your system will ever really like running at.

[gmcenroe]

That definitely sounds like a thermal cut-off fuse. SGI used those pretty extensively and they act exactly as you describe--preventing a restart until the fuse cools and either closes or opens the circuit, depending on how it's designed.

Above 80 for an Indigo2 could be an issue depending on airflow, what boards are installed, and to weblacky's point, the age of the PSU. I'll say that when I run my Indigo2 my room is cooled to around 72-74 and I typically measure output exhaust at 92-95 degrees at the front fan and PSU fan. I would imagine if your system is more sensitive to heat due to age that's where the issue may lie.

Ultimately SGI made these systems to run inside cold office environments so above 80 may not be something your system will ever really like running at.

Thanks! I will shut it down on hot days since I don't have an air conditioned environment to run  it in.