I am looking into doing my final mod for my Pentium I 150 MHz server. It's made of "junk" parts salvaged from dead PCs so I'm not too worried about overheating, But I have a new Barracuda V ST360015A in it which I would REALLY hate to cook.

I was wondering if a Panaflo L in the AT powersupply would suck enough air out to cool the Barracuda. At the moment it is reading 48 degrees with an ambient temp of 25deg. Before I started soldering in resistors it measured 38-46 degrees using a stock quietISH (compared to other blowers i've seen) 486 powersupply. The range now 42-49 degrees depending on ambient temp. The 'cudas are rated 0-60 deg I think. And from memory mine runs at 38-40 with the case open.

I have cut off the stamped grill over the fan on the powersupply, and done the "opening the blinds" mod on the vents on the inside. I also removed a the second bottom PCI slot cover (it's a tower case) to allow half decent intake since there isn't any intake anywhere else on the case! It was a generic case dating back to '94 when 486s were all the rage.

Anyway, would a 12V panaflo in PSU in a AT tower case with ONLY that fan to move air be ok? And what temps do other people with Barracuda Vs get? what temp do you guys get nervous with?

I get nervous with anything over the low 40°C range for more than a short period of time. I use a 5V 92mm L1A in front of my Barracudas (IV's and V's) to cool them. It's inaudible from more than 2-3 feet away. Typical drive temps for me range from case temp to +1°C over case temp as long as the drives are fan cooled. Without a fan temps will raise about 8-9°C over case temp. (For instance, right now ambient temp is 72°C, case temp is 29°C and HDD temp is 30°C. Without the fan to cool the HDD I would expect to see drive temps around 38-39°C which is OK, but it's 6:30 AM right now and it will be +25°F in here later today and the HDD temp will raise right along with the ambient temp)

I highly doubt that a 12V L1A in a PSU would be enough to cool your drive. My current case with a 5V 120mm L1A as an exhaust fan + PSU exhaust will not cool the HDD at all. It needs that little bit of extra airflow from the 5V 92mm L1A blowing over it to keep it cool eough for me.

Ralf: Are you saying I should be nervous if my HDD's temps are pending around 41-43°C (except during startup of course)?

Nah, you'll probably be fine.

I'm just real nervous about HDD failures and I've had super-good luck with drives that have been kept cool, and so-so luck with drives that have been mounted with no active cooling and allowed to get hot (over 45-50°C).

According to the manufacturer's spec pages, the max safe operating temp for most hard drives (check yours, to be sure) is ~55c.

I'm not sure why anything within this range would be "less safe", per se.. of course cooler is better generally speaking, but as long as you're not exceeding the manufacturer's maximum specifed temps-- that is clearly dangerous-- why be overly concerned?

The BV drives are temp-spec rated up to 60C. You are just fine with those temps, no need whatsoever to worry about it.

Putting another undervolted fan blowing over the HD sounds like a good idea Ralf thanks! I would like my HD back down at 42 or so. I'll crack open the case and see if there is anywhere i can attach it. Pity it is a cruddy old case.

I'll order 2 panaflos then and see how we go.

By the way does anyone know about how to use zener diodes properly? I heard then drop the voltage a fixed amount and don't affect current quite like standard resistors. Therefore allow full current to start the fan. Google didn't help much.

I've been using ceramic 5W resistors 82ohm in series and a 47 ohm + switch in parallel to short out the 82 down to 47 for extra cooling. So i have no idea what voltage my fan is running at.

Will an 80mm Panaflo L1 placed in FRONT of the Barracuda V be enough to cool it down?

Absolutely. It'll definitely be enough even if it's running at 7 volts. 5 volts may me a little low. It's barely enough for the Barracuda IV and the V runs a few degrees C warmer than the IV's.

On the other hand, 5V is probably worth a try too... My 2 stacked & suspended B-IV 40Gs, located at the bottom from of an airflow-maximized case, are currently reading 40C and 35C. These are perfectly safe temps. There is a Panaflo 80L at 5V at the intake vent directly in front of the HDDs. Ambient in the room is 22C.

I've checked my temperatures and they read as follows:

ambient HDtemp Difference Conditions
28 46 18 Case open
28 51 23 Case on - slow fan speed
27 49 22 Case on - fast

the fast and slow fan speeds are the fan in the AT PSU, there aren't any other fans moving air in or out of the system.

Mike your 40deg HD is only 18 deg warmer than ambient! which is the same as my entrire case open!, I better look at getting a fan to blow over the hard drive (barracuda V) but there isn't much room in there, its a tiny AT tower case, only room for 2 CD drives and a couple of floppies.

How can I read the temperature of my Barracuda 7200.7 SATA hard drives? Is this feasible through software?

Dtemp - check in useful web links / software

My older system's HD (Samsung SP1213N) is only 33-35°C in 21°C ambient. Same as the case temp. I don't have a dedicated HD fan, but I think that the 120 mm Enermax @ less than 5V mounted over the cards creates some air movement around the HD.

I don't know how the 3.5" bays are located, but You could try placing the HD near the 3.5" bays meant for floppy drives, and leave the cover plate off. As You mentioned, your case has almost no intake holes, so most likely air will go in through the opening, especially if You replace that PCI slot cover.

You could also try to place the HDD near the card bays (put some foam under it), and leave one or two slot covers off, maybe this will suffice.

Barracuda V seems to be the hottest running Seagate, especially the SATA version.

Cheers,

Jan

I think next time i'll put some thought into how much heat the Hard drive generates when i'm buying another. A HD only 13 deg above ambient (like yours Jan) would be nice!

Thanks for the suggestion Jan about moving the hard drive to the floppy bay and leaving the cover off. I currently have two floppy drive installed but for hard drive longevity during summer i'll live without two. The floppy drive bay cover is moulded to look like a floppy drive, so I might try and cut out the slot. (just had a funny thought about people "posting" floppys through the fake floppy cover if i cut it all away!). If that isn't enough i'll just leave it off and live with the gap.

There isn't any room down at the back to mount it infront of the card slots. And moving the HD to the floppy position will be fiddly because I can't reach all the screws without removing other things. I'll see how i go.

Thanks!

I run a 5v L1A in front of my suspended 7200.7. Its temperature almost exactly tracks the board temperature. The highest I've ever seen it was 32 degrees C, and that was copying files on a warm day.

isn't that body temperature?

No, 32°C is just about 90°F, "normal" body temp is 98.6°F which is 37°C.

I just removed the second floppy drive and put the Seagate Barracuda in its place, and left the face plate off. I also covered the PCI slot I had removed earlier. And the temperature drop is AMAZING!

With an ambient of 22^C I get a HD temperature of 36^C after an uptime of a hour and a half. Thats only 14 degress above ambient! When before with it mounted in the usual HD position, and no airflow accross the HD it was 24 degrees above ambient! Or around 46 for an ambient of 22^C.

10 degrees Cooler! Thanks Jan!

Now I think I safely slow the PSU fan down further. HMM, panaflo here I come!

Does anyone know if any components of early pentiums are vulnerable to overheating, other than the processor? Its pentium I 150MHz 7 volted and it was neither cool nor warm to touch (ie prolly around 35) before i did this mod. I'll open the case and check that again later.

You're welcome!

I'm a bit concerned about the possible increase in noise though; as the drive is not totally inside the case anymore. Well, You win some, You lose some...

Cheers,

Jan

There is an increase in noise, but it is mainly seek noises, not the idle noise. I actually don't mind being able to slightly hear the seeks. I still find it kind of unnerving without them. The hard drive is still just screwed in, the case is too small for fancy setups.

However the PSU fan is still far louder than the HD, or the 7 volted pentium I fan. So with better airflow I can now slow it down, or get a better fan.

Has anyone had problems with fans stalling? Just curious because at the current speed the PSU fan definitely won't stall, but being a 1991 Forton/Source 250W PSU transplanted from a deceased 386 its, well, old and I guess might stall or fail to start if I slow it down too much further. Just worried that it might be fine when stopped with fingers now, but mysteriously one day jam.

I saw someone linked to this thread regarding HD temp.
So I just thought I'd update the final outcome.

I did put a Panaflo in the old PSU. This further droped temperatures for the same noise level. So I then soldered in a Zener to run at 8 Volts:
http://forums.silentpcreview.com/viewtopic.php?t=14753
And made it even quieter.

Since then the drive temperatures have been around 41^C (or 14^C above ambient temp). The same as with the old fan and resistors, but now it's really quiet. (or at least quiet enough for me. I don't know if 8V panaflo on rubber mounts is considered quiet around here)

And by the way Jan, because of the placement of the mounting holes on the HD vs the FLoppy, the HD actually sits back within the case, and not flush with the front like the floppy drive does. It doesn't seem to contribute to the noise much. PSU is still noisier.

Well I think my modding is now finished. till I decide to get a faster computer.

I think you just want a regular diode for what you're talking about. I have a standard diode wired in-series with the power wire to one of my fans, and it drops the voltage by about 3/4ths of a volt. You can string several diodes together to make a bigger voltage drop. Zener diodes give more drastic voltage drops, I think (my knowledge of this stuff is a bit rusty, and was dull to begin with )

Regarding the current: as long as the fan's resistance stays constant (and I have no idea if does), lowering the voltage will always decrease the current draw by merit of Ohm's Law, so whether you use a resistor or a diode, the fan will use the same number of milliamps. You are correct, though, that the diode won't consume current like a resistor will, because the diode doesn't present much resistance. In the grand scheme of things, this only matters if you are running about 50 fans.

Edit: oops, I just looked at the timeline for this thread. Well, maybe you were still wondering about zener's for the past two and a half months.

That was actually a year and two months ago! I was just updating the final results and linking with how I did it in another thread.

I used a zener because in reverse they have the drastic voltage drop you mentioned. Mine was about 4V drop in reverse polarity to get it down to around 8V. Saves putting a stack of ordinary diodes in series!

I'm not sure why more people don't do it. Makes sense to me, and is a constant drop, not like trying to guess with resistors. It seems like very few others round here do it...