So I've just disconnected all of the fans...

IsaacKuo · Post by **IsaacKuo** » Thu Mar 31, 2005 9:59 pm

I have my slot 1 PIII system's components just lying around in the air right now, and I've disconnected the one remaining fan (the PSU fan).

What sort of failure mode can I expect if my PSU or CPU overheats? Is this going to cause permanent damage if I foolishly leave the system as is?

The CPU is cooled by a Zalman ZM-80A VGA cooler, and I'm pretty sure it will stay cool enough indefinitely just by passive heat loss.

The PSU, OTOH, is a 300w Enlight PSU of dubious quality. I've opened up the grills so there's plenty of free space for passive airflow to occur...but I really have no idea if it's enough. If I place my hand over the top grill, I definitely feel warmth from the two big heat sinks.

Am I begging for a capacitor to pop, or something else permanent?

Thanks!

Edit: BTW, this system is silent! The notebook hard drive is enclosed within a 3.5" drive within the original all-around foam packaging, rendering it inaudible unless you put your ear up next to it. I'm still going for complete silence with further enclosing, though...

m0002a · Post by **m0002a** » Thu Mar 31, 2005 11:19 pm

I think I smell something burning.

niels007 · Post by **niels007** » Fri Apr 01, 2005 2:28 am

If it works, great, but it is a bit risky. I would definitely want a few temperature probes to check the PSU heatsinks and cpu temperatures!

ultraboy · Post by **ultraboy** » Fri Apr 01, 2005 5:46 am

niels007 wrote:If it works, great, but it is a bit risky. I would definitely want a few temperature probes to check the PSU heatsinks and cpu temperatures!

...and also HDD eventhough notebook harddrive probably can take higher heat.

IsaacKuo · Post by **IsaacKuo** » Fri Apr 01, 2005 6:47 am

I wimped out and put an undervolted fan next to the PSU to blow air onto it overnight. I left the CPU to cool purely passively. In the morning, the Zalman ZM80A heat sink was certainly warmer than when I used to have active airflow blowing past it, but as I expected it wasn't excessively hot.

Tonight I may test how things go with the fan removed so the PSU is passive also. When I remove airflow, it feels like the heat sinks quickly heat up to a particular temperature but then remain there (based on felt radiant heat--I'm not quite stupid enough to perform the "finger test" on PSU inards).

My plan this weekend is to build a scratchbuilt case around this system incorporating a solid state airflow generator (a light bulb inside a chimney to suck air out of the case). I'm not relying on pure passive heating, but OTOH I'm not expecting this solid state airflow generator to create a whole lot of airflow. Given the easy survival of my CPU under pure passive conditions, I'll develop the case with no CPU duct at first to speed up construction.

The hard drive has already survived for days within its heavily insulated enclosure. I took it out once to find it very warm, but not exceptionally so compared to how hot a typical laptop bottom gets. Ambient temperatures in the last few days are about as hot as it gets here before I turn on the AC, so I think it's fine.

IsaacKuo · Post by **IsaacKuo** » Sat Apr 02, 2005 7:21 am

Well, my rig survived a full night fanless, so I know it's fine with my typical usage pattern (mostly idling and web browsing). Now I just have to go to the hardware store and make my solid state airflow generator, and this system should be good to go...

Unfortunately, I can still barely hear the old laptop drive, since it's now the only sound source. I want absolute silence, so I'll see what I can get at the hardware store...

StarfishChris · Post by **StarfishChris** » Sat Apr 02, 2005 8:07 am

A large hammer should do it.

IsaacKuo · Post by **IsaacKuo** » Sat Apr 02, 2005 8:17 am

Aaaarggghhh!!! CRT monitor coil whine!!!!

My CRT is an old 21", and a while back it started developing coil whine at higher resolutions. It's the main reason I run 2048x1536 interlaced rather than noninterlaced (this reduces the horizontal and vertical sync rate down to 1024x768 rates). I just noticed that the CRT has started intermittently whining at 2048x1536i @ 85hz...

It took me a while to correctly identify it, because the whine is intermittent and almost exactly matches the frequency of my notebook hard drive whine.

So I've dropped my refresh rate to 75hz and now enjoy silence. Now interlace flicker is noticeable.

What an ugly tradeoff dilemma! If this monitor starts whining at 75hz I don't think I can live with going much lower.

IsaacKuo · Post by **IsaacKuo** » Sun Apr 03, 2005 7:10 am

My PSU didn't make it through last night unscathed. It now makes a soft rattling noise, a bit like something rattling in an air conditioning duct. I have no idea what the sound is, but it didn't stop when I allowed the PSU to cool down and put an undervolted fan on the PSU. I think I'll have to swap the PSU to acheive solid state silence.

I also heard some low grunting noises which I couldn't identify, but I'm not sure those noises were coming from the computer at all.

Viperoni · Post by **Viperoni** » Sun Apr 03, 2005 4:51 pm

On my near silent rig, a p2 400 @ 448 with an Alpha p60f120 (or something like that) passive heatsink, 384mb RAM, Samsung SP1604N, I needed a 80mm Panaflo L @ 5v to keep my FSP 300w cool. It ran just a bit too hot for comfort. Otherwise the CPU handles the heat fine, but the HS is MASSIVE with a ton of surface area for a p2.