Passive or near-silent AT PSU for my old school DOS Box?

Mike01Hawk · Post by **Mike01Hawk** » Wed Mar 19, 2008 8:30 am

Man, the PSUs in these old 486/Pentium 1 boxes are LOUD!!!!!

I found this StarTech AT 230W over at Newegg:
http://www.newegg.com/Product/Product.a ... 6817707002

It comes w/ a 80mm that looks like it's a 3 speed variable fan which I would think be a fantastic starting point for my old Pentium 200mhz, but I'm wondering if there's something out there that would be quieter.

My application:

Pentium 200
2 Hard drives
1 CD-ROM
1 Floppy
2 ISA Sound cards (Soundscape and SB16, yes, it's twisted to have two in the same machine)
1 MPU-401 ISA card (hosts a Roland Sound Canvas Daughterboard

And an interface to my Roland MT-32

)
1 Ethernet Card
1 Video, either basic VESA, or a VooDoo3 depending on the game I'm playing.

I have room in my box to put a 120mm fan, and of course will have Arctic Silver on my heatsink for my CPU, may or may not run a fan on the CPU Heatsink, depends on if the 120 will be enough, or if the CPU fan is 'loud'.

Any help would be appreciated.

scdr · Post by **scdr** » Wed Mar 19, 2008 9:49 am

Seems a shame to build a new AT power supply when there are thousands of already made ones going to the dump. (I got rid of many of my old AT supplies a few months ago when there was a computer recycling drive.)

Shouldn't be too hard to find something not too loud second hand for
practically nothing. (At least if you are near a city.)

Or see if you can attach a 120mm fan to your existing supply.
(E.g. if there is space below the supply to make it blow in through the
bottom vent, possibly cutting away some of the cover.)

I might even still have one or two AT supplies that use 120mm fans
if interested (don't know how loud the fans are).

Mike01Hawk · Post by **Mike01Hawk** » Wed Mar 19, 2008 10:43 am

Well who woulda thunk it, they make a ATX to AT power supply cable adapter / converter! That opens up a LOT of opportunities to find a passive / silent PSU

BillyBuerger · Post by **BillyBuerger** » Wed Mar 19, 2008 12:00 pm

Mike01Hawk wrote:Well who woulda thunk it, they make a ATX to AT power supply cable adapter / converter! That opens up a LOT of opportunities to find a passive / silent PSU

Yeah, that would be one of my suggestions. The other would be a simple fan swap and/or hard-wire the PSU fan to 5V. In the old AT PCs, the PSU fan was many times the only fan. So they just left it sit there at 12V blaring away spitting out mostly just cold air. But given how dusty I've seen some old PCs, it's good that they did this or they would have overheated from the dust. But aside from that, there's no need for them to run that fast. Much cheaper this way if you're willing to crack open your PSU.

yukon · Post by **yukon** » Wed Mar 19, 2008 2:59 pm

Check power usage. Old computers might not use much. You could look into buying that adapter, and one of the low-wattage silent external PSUs.

scdr · Post by **scdr** » Wed Mar 19, 2008 5:59 pm

Another option - move to a motherboard that has ATX power connectors. Lots of them did (some had AT and ATX connects).

wwenze · Post by **wwenze** » Sat Mar 22, 2008 8:16 pm

Not to pour cold water, but the money you're paying for that new PSU may be more than what your rig is worth currently.

Unless your MIDI card is really important, which I doubt it is, considering how much computer sound technology has improved. You would get much better sound by moving onto a new high-end soundcard, so why no treat yourself to an upgrade while solving the issue at hand?

Or, just move on, buy a Pentium 3 or Athlon class mainboard + cpu 2nd hand. These should still have an ISA slot, and the extra processing power is useful for audio production.

mcoleg · Post by **mcoleg** » Sun Mar 23, 2008 7:21 pm

just swap the fan in it - that would be the cheapest solution.

this nmb 80mm is relatively quiet:

http://www.sidewindercomputers.com/nmb80ulqubr3.html

might not be as "silent" as more popular options but it also costs 1/8 of the price.

the 3-pin connector looks different than the usual but it fits anywhere a regular 3-pin does.

if the fan will need some adapters (and you don't want to cut the wires), here's some adapters that will do:

http://www.coolerguys.com/32pa.html

if the psu works fine, there's really no reason to change it. buying new stuff simply means accumulating junk that you don't use - believe me, i know

p.s. noticed the fan is out of stock; they have it pretty often though. or check around for other cheap options.

Mike01Hawk · Post by **Mike01Hawk** » Mon Mar 24, 2008 6:06 am

yukon, yeah I'll have to check out my power usage (hopefully I can do that via software) once I have everything set up.

scdr, I'd like to stay with my GA-586HX AT board cause it has 4 ISA slots and 4 PCI slots

wwenze, I'm a old school purist

Pentium 1 200s seem to be a sweet spot for 90's MS-DOS gaming. Oh and and Roland is king

Ain't no way I'd try to replace the wonderful sounds of MT-32 or Sound Canvas with some soundfronts on a new rig.

Just to give you an example of some of the greatness that is known as Roland, here are some sample comparisons:

Ultima on a Adlib
Ultima on a LAPC-1 / MT-32

FM Synth
Same song, using Sound Canvas
Some more places to check out

http://www.dosforum.de/soundcards/
http://dor-lomin.com/archive/ultima/musicarchive/u6/
http://alag3.mfa.kfki.hu/dcsabas/hi-fi/waveopl4.htm

mcoleg Well I manually 'spun' the fan on my PSU when the PC was on, and it started to spin again, guess it just needed a kick start. I'll monitor it very VERY closely and not have any extended gaming sessions for the time being. But yeah, I'll look into the fan replacement route as well.

It really all boils down to I'll do whatever it takes ($$$) to protect all those sounds cards I have hooked up (Sound Canvas, via SCB-55. XG via Yamaha DB50xg. Roland MT-32, Ensoniq Sound Scape, etc etc

)

edh · Post by **edh** » Mon Mar 24, 2008 6:22 am

I would go for the approach of fan modding your existing AT PSU. It seems like many PSU's just get thrown away as the fan wears out which is a waste, I've done it before but wouldn't do now, it's just all of the over the top warnings you see on them about danger of death that stop most people from thinking they're serviceable.

I'm typing this on a heavily upgraded PC with an ATX power supply sold with the original system in January 1997. I did have to mod it last year to flip the 92mm fan on it round, changing the airflow and allowing for a Pentium 3 to sit in it, something the previously outboard fan prevented.

What you want to do to mount a 120mm fan is take the cover off as it will be an entirely separate part and have nothing connected to the rest of the PSU (probably) and then see if you have 25mm of height clearence inside to sit an inboard 120mm fan. If so, find a 120mm fan which matches the airflow of the 80mm, drill a big hole and mount it there, powering it from the same internal header if you're brave or from an external molex connector if you're scared.

If you think you might want more CPU cooling, check that the CPU heatsink actually has thermal paste, most from that period didn't. When this machine had it's previous P166MMX in it, there was no thermal paste until I found out a few years ago and bunged some cheap generic stuff on it and took it up to 200MHz. A Petium MMX might also be worth considering for you as it has lower power consumption and therefore lower heat, despite being more powerful in many things.

Mike01Hawk · Post by **Mike01Hawk** » Mon Mar 24, 2008 6:59 am

edh,

Thanks for the advice, yeah, I may just crack open this old PSU and swap fans.... after I fill out a will.

I actually have 3 CPU chipsets to mess around with:

P166 that came with HSF (heat sink + fan)
P200 that came with HS (no fan)
P200mmx came with HSF

I'll definately throw some proper thermal paste on when I get the box to my final revision.

I also have enough room up front in the box to double-sided tape mount a 120mm fan, this'll work great for me cause it's right next to the CPU, and will also blow some air over the ISA cards.

I'll have to get some pics together to show you all whats going on, but for now here's just the MOBO layout

Check out my mad MSPaint Skillz