G4 Mac Power supply really loud

Umm. Best to find out exactly what's wrong first. Could be a software issue. The fans are variable speed and can run flat out if there's a hiccup in the software that controls them, and also if they need to because it's hot in there.

However, the tower G4s are famously noisy, some of them.

Not the same at all: totally different.

Erm.

See if you can isolate the fault properly. Could be that someone has a spare of what you need. Well, I possibly have, but I'm not up to offering to do anything for anyone at the moment (if it weren't for that and the model's right, I'd offer you a PSU for postage).

Rowland.

There was an issue with G4 (Mirrored Drive Doors) PSU noisiness - I have a G4 dual 867 which sounded like a vacuum cleaner before I replaced the PSU - and Apple had a replacement program for them, but this seems to have ended in 2003. https://depot.info.apple.com/generic/index.html

The replacement PSU they supplied was quieter, but it's still noisier than any other Mac I've owned.

I'm afraid I don't know if the PSU is the same as the PC version, but you could try searching/asking in the Apple discussion forums, e.g. here:

<http://discussions.apple.com/thread.jspa?messageID=2976890&#2976890>

HTH
Deb.

Oh yes lots! My old 2G4 ran a lot quieter if I took the trouble to clean out the dust every few weeks. Lots of dust all over the place needed removing.

Do the deed with the Mac *plugged in to the mains*.

Yes, that's right - but make sure that the power is turned off at the wall socket too.

That way, you keep the machine earthed.

Caution: do not let any of the fans get themselves spun round by the vacuuming process. Slow rotation by hand is okay, but an electric motor being driven mechanically tends to behave as a generator, doesn't it? Right.

[snip]

If the PSU packs up, don't throw the machine away. Ask me.

Rowland.

And main fan, surely?

FWIW, I had the same - but memory says it was a 1.25Ghz 2G4.

- and Apple had a replacement program for them, but this seems to have ended in 2003. https://depot.info.apple.com/generic/index.html

The replacement PSU they supplied was quieter, but it's still noisier than any other Mac I've owned.

[snip]

It was quieter - just about - at low running speeds. But at higher running speeds, I'm not sure the noise was any less annoying. The replacement kit kicked out higher frequency sound which was more annoying to my ears when running fast.

Rowland.

Rowland McDonnell wrote:

And main fan, surely?

Ummm - can't remember, TBH. All that was sent by Apple under this replacement scheme was the large metal power supply box thing (technical term :-) ) which does have a small fan in it, IIRC. But without opening up my Mac I can't be sure if that's also the main fan, or if that's separate. I have a feeling that's elsewhere inside.

Deb.

How very British.

That way, you keep the machine earthed.

Caution: do not let any of the fans get themselves spun round by the vacuuming process. Slow rotation by hand is okay, but an electric motor being driven mechanically tends to behave as a generator, doesn't it? Right.

You are exaggerating greatly.
(as in the case of the excessively dangerous high voltage
in the Mac Plus)
Can you cite any example at all of a PSU being blown up
by vacuuming the fan?

Jan

Previously, LongJohn wrote:

Am I really OK to vacuum the inside of my mac? This seems like a dodgy thing to do.

Oh heavens yes! I've been doing that for years with no ill effects.

I've heard stories about vacuums generating static, but I've never had any problems myself.

Paul

Mere vacuuming isn't enough.
The dirt collects on the leading edge of the fan blades,
and has te be rubbed or blown off
to restore the clean aerodynamic shape.

Jan

What I did in that case was pass on the warnings from the Apple Service Source CD which explained how to discharge the CRT's potentially fatal charge. It was Apple which made the initial claim of the danger of the charge that you might be facing - Apple's advice was `Always discharge using this procedure.'

So I think it's pretty clear I wasn't exaggerating at all. Of course, if you want to risk it and assume that you'll not get zapped or blow up some internal circuitry (another specific risk mentioned by Apple and the compact Mac service book I have), you go ahead. You might well get lucky. Personally, I'd rather heed the warnings given by the people who really know about this sort of stuff.

Can you cite any example at all of a PSU being blown up by vacuuming the fan?

The positioning of the PSU fans and the vacuum cleaner tools available to me are such that it was impossible to vacuum the PSU fans effectively without first removing the PSU. What I could do involved shoving the bristles of the brush tool into the fans at an oblique angle; they couldn't spin.

I have had trouble from letting one internal fan spin quickly when vacuuming inside my old 2G4 - it behaved very strangely afterwards. It wouldn't start up at first, and just beeped continuously. Unplugged from the mains, plugged back in again, booted into single user mode, all was okay.

Rowland.

Oh right - sounds like a different arrangement to what I thought. Y'see, I though you had the same noisy G4 I had, which also had the noisy bits replaced for free by Apple. We got a replacement PSU with two small fans inside it, and a single replacement main fan - quite a big one.

Doing the swap was maddening - Apple's instructions were wrong, and neglected to mention *that* screw... Found it eventually.

Rowland.

That doesn't mean there is any real danger involved in practice.

Impossible to say what happened. You did other things too. My guess would be a case of post hoc, ergo propter hoc.
Or as you say elsewhere: Gawd knows...

You didn't try to reproduce, I assume?

Jan

Another imaginary one, under the circumstances.
If you were pouring hundreds of tons of grain
you might have to worry about an industrial dust explosion.

What you want to do is keep the Mac plugged in to the mains but switched off at the wall too - that way, it'll be earthed (important!) and completely electrically `off' (pretty much - let's not talk about the neutral line, eh?).

Don't vacuum close to open PCI slots or any other electrical terminals - they're the bits that are in a position to suffer from static (although USB and Firewire ports are pretty damned robust when it comes to electrical abuse; don't worry overmuch about them). Just vacuum the dusty bits around the fans and HDDs and whatnot, clean out the grills, and carefully clean the CPU heatsinks.

More nonsense. Charging up the machine is no problem.
Only charging up parts differently might cause problems. Your vacuum cleaner won't be doing that.

Best,

Jan

Previously, J. J. Lodder wrote:

[snip]

Britain is unique in having choosen
a potentially unsafe home wiring system,
with the corresponding need for switches and fuses in plugs. It may save a few pennies worth of copper.

[snip]

It is noticeable that other countries don't have switches in their sockets. Personally I find it useful - means we can switch off e.g. the whole TV setup (otherwise lots of boxes on standby) each night without having to unplug anything. *Much* more convenient.

But I would be interested in your characterisation of it as "potentially unsafe" - could you explain a bit (or a lot :-)

I feel the Yanks have the unsafe one, with their cheese-paring 110 volts and so four times the heating effect anywhere there is a poor connection in the circuit.

Tim Streater wrote:

I feel the Yanks have the unsafe one, with their cheese-paring 110 volts and so four times the heating effect anywhere there is a poor connection in the circuit.

Indeed. But 110V AC is *human* safe, whereas 230V is smack in the most lethal range.

There has to be a trade-off; I wonder how many fatal house fires are started by the doubled current values in the Yank system, as against the extra deaths by electrocution in the European system?

Oh, get out. I've blown up static sensitive electronics more times than you've had hot dinners, at a guess.

I'm telling you, it's a real risk.

More nonsense.

There's no point in trying to explain, but you are entirely wrong in your assumptions.

Rowland.

Yes, this is a good question. Having lived there I found that there is a variety of plugs - 2-pin, 2-pin polarised, three pin - and corresponding sockets. So you can't plug a 2-pin polarised in a 2-pin socket (one blade is a bit bigger that the other). Houses also have 240 anyway to run the washing machine etc - and a variety of plugs for that, too. You can't buy a regular 3-pin plug to wire yourself - the ones you can wire are ugly as sin and look industrial.

The pins on any 3-pin plug are bendy - and the whole plug can easily be kicked out of the socket by accident, especially if its on the end of an extension socket strip, the cable is almost as fat as your finger.

The worst thing I saw was a sort of 2-pin socket strip - but the pin-holes were each about 15cm long. So you could pplu in as many 2-pin plugs as there was physically room for. When I examined this item, it was quite hot.

Double the current means four times the heating effect, don't forget.

It's the ring which is potentially dangerous, when broken.

I feel the Yanks have the unsafe one, with their cheese-paring 110 volts and so four times the heating effect anywhere there is a poor connection in the circuit.

Indeed, the European 230 Volt system is probably much safer. (but good statistics are hard to find)

Many more people are killed in electricity related fires than by electric shock.

Best,

Jan

Actually, 110V DC which is where the Yanks started[1] isn't at all human safe. And 110V AC and 10A (or whatever they can get) is plenty enough to start a fire. And in any case, 110V AC can kill a person - if said person is frail or unlucky.

But how many such `extra deaths' are there? We, for example, do tend to have proper earthing, unlike in the USA. I wouldn't be surprised if that bumps up their death by electrocution rate.

Rowland.

[1] That total wanker rip-off lying evil bastard Thomas Edison gave 'em that shite setup.

I'm sorry? You think I should be more polite about the inventor of the electric chair, possibly the cruellest form of legalised murder used by any nation today? The man who shamelessly stole his employees inventions? Etc?

Not completely. I was able to buy one while living there (a Russell-Hobbs). But electric turn-themselves-off kettles are not normally part of their national psyche.

Rowland McDonnell wrote:

[1] That total wanker rip-off lying evil bastard Thomas Edison gave 'em that shite setup.

<http://www-static.cc.gatech.edu/~jimmyd/laurie-anderson/lyrics/UnitedSt ates.txt> and search for "electricity".

Daniele

But it is immediately obvious that they can't be civilized, for (due to their puny 110 V supply) they lack electric kettles. They have centre-tapped 220 V, 2*110 Volt
and call that (incorrectly of course) two-phase.

Jan

But it's so sloow.

But electric turn-themselves-off kettles are not normally part of their national psyche.

Indeed, no tea,

Jan

They drink tea all right, just *bad* tea made with off-the-boil water.

I visited Dallas once...

Rowland.

Rowland McDonnell wrote:

Really, European mains voltage is *okay*, just about. Potentially fatal for sure, but so's 110 V AC and the old 110V DC US system was *horribly* dangerous.

Electrical safety officers I've talked to disagree with you. 110V AC is pretty safe, 230V is bloody dangerous. The conducting path goes through the body. Much above that, the conducting path is via the outside of the body, and danger falls off again. Then the main risk is burns at the contact points. At Imperial College we were given an electrical safety lecture by a safety officer from the CEGB, who was on sick leave because he'd reached up to a 1500V bus which should have been isolated, but was actually live. He woke up with the palms of his hands and the soles of his feet severely burnt, but his heart was okay. He said that was entirely down to the high voltage on the bus, and that at 230V he'd have been dead.

So what? You've got to be unlucky for a shock to stop your heart, really. Your body seems quite good at keeping itself running.

That's why the electric chair is such an evil way of killing people - it kills not by stopping the heart, but by cooking the victim slowly and hideously painfully.

He said that was
entirely down to the high voltage on the bus, and that at 230V he'd have been dead.

He was talking total bollocks - and back then, it was 240V, right?

Rowland.

Rowland McDonnell wrote:

Anyway, that should be enough to convince you that this `high voltage down the outside' idea is bullshit. High /frequency/ goes down the outside, yes - hence lightning survivability.

You don't convince me at all. And the wrongness of your reasoning is absolutely clear from your statement that "And you know, if the conduction path was down the outside as you claim, you'd not just have contact burns, would you? No, you'd also have burn tracks on the skin". Of course you do- at the contact points, where the current density is highest. Elsewhere the current is flowing over the whole skin surface and the density is much lower.

I'll go with the CEGB safety officer.

You look at those who survive lightning - I've seen *them* with burn tracks running down the outside.

I'll go with the CEGB safety officer.

<shrug> I'll go with the electrical safety people who taught me.

Rowland.

If you have a dual processor mirror drive door G4, it most likely has the original noisy fans.

I had one of these and I bought replacement fans from here:

http://www.pcsilent.de/en_pd_smartCooler_fan_set_for_Apple_PowerMac_G4_q uieten_Apple_Power_Macintosh_G4_quiet_powermac_LFS1130_307.html

Seeing as this model G4 is very old now and not worth much, it may not be worth paying for the replacement fans which cost me 40 odd pounds at the time, but they did work very well.

Previously I did look on eBay for replacement power supply/fan, but these were going for silly prices at the time.

And here are the instructions on how to replace the fans:

http://www.xlr8yourmac.com/systems/g4_mirrored_drive_doors/noise_reducti on/g4_ddr_noise_reduction.html

FWIW, I'm with Roland here. It's a silly argument though.

The points to remember are:

Anything over about 60V can kill you under some circumstances.

It's current which kills, so contact area and the internal resistance of the source matter, and by virtue of Ohm's law higher voltages are more dangerous.

The most dangerous shock is one where the current flows from hand to hand. If you work with high voltage you develop a reflex which prevents you from touching two metal surfaces simultaneously with your left and right hands. (And you always wear rubber-soled shoes.)

Phil Taylor

Skin resistance is very, very variable - that matters, too, and it's more significant that source impedance most of the time (but note that HT PSUs are often equipped with a high impedance output to give you a bit of protection). Hot and sweaty? You're in trouble.

Umm. You don't have to work with particularly high voltages to develop the reflex. Just mains has been enough to scare that way of working into me. Oh yeah, and anything that feels like electrical tingling makes me jump - and whatever was tingling gets jerked away very fast. I'm pretty sure that reflex has spared me some damage.

Rowland.