Got hold of a Beige G3 MT 300mhz clocked to 333/222/66, it's hot and really noisey. I have made 2 adjustments so far.

One 12v 30mm fan placed to the side of the heatsink blowing accross it.

Second I removed the case fan which seems the most noisey removed it from the casing it was in, turned it backwards so it blows air and mounted it straight on to the chassis facing the motherboard.

Have managed to keep the temp between 44c - 48c so far.This seemed to have decreased the noise a little.

Now that the case fan is blowing air against the motherboard would this cause long term damaged to the components? now that it is no longer extracting the hot air from inside it could just be blowing alot of hot air around?

I am still looking for a Quieter 120mm fan but am unshore as to how many Amps this should be? more amps the Quieter? I tried one fan i had from an 8100 Power supply the specs were "12v 0.35a" when i plugged it in it made more noise than the exsisting one. so i guess i'd need more amps to slow i'ts rotational speed down?

I am also concidering an ATX power supply replacement but are uncertain it would work.
I have two power supplies from old PC's would these work? I noticed looking at the ratings all the voltages are the same but the Amps are slightly under would this fry the motherboard if under powered? or would i need the same specs as the original supply 171watts total.Could i use a more powerful supply like a 2, 3 or 400watt supply?

Any help would be greatly appreciated.

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Regarding the PSU: Yes, a standard ATX psu will work on that paticluar mac, theres a little jumper that needs to be changed from mac to ps/2 (not sure that its called ps2) power supply. You should be able to find it if you quickly scan the motherboard.

Hmm it shoulden't harm the motherboard to underpower it, but you might risk the PSU is overheating (thats nasty). So i would definately buy a ATX supply which at least matches the beige's psu in watt rating. A bit larger psu might be good if your adding lots of fans, HD's etc.

Edit: actually theres already a beige g3 to atx mod here on macmod.

[*]http://www.macmod.com/content/view/137/66/

Heres a picture of the jumper (taken from the above guide)


Post edited by: griffer, at: 2005/06/14 12:13

Ohh regarding the fan, the amp rating haven't got anything to do with noise level. It simply tells you how much power the fan "draws" from the psu.

The thing your looking after is the DB level of the fan (lower value means less noise), which tells you how noisy it is. You should also look at it's ability to move air (cfm) the higher value the more air is being pressed through the fan.

hey thanks, just the info i needed. I am now in " search and buy mode" for a new PSU and case fan.

I'm just wondering if any one has tried turning their case fans in the oppisite direction? "Extraction Vs cooling".

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