Mac mini G4 FireWire issue

[joshjohnson]

I have found trying to use a bus powered FireWire hard drive (an owc mercury on the go) to be a bit frustrating. If I try to use the drive connected directly to the Mac it can fail to be seen by the Mac and OS X. If I use a bus powered belkin fw400 hub it works but can fail to be seen by the Mac and OS X if I leave it powered on or connected for a while with the Mac mini powered off but plugged in. Is there a particular capacitor that is used by the FireWire port that I can check? Should I just replace the 3 electrolytic capacitors? I wish to use more peripherals like a Canopus ADVC and other devices that just work better over FireWire but I want a stable port. Should I just keep using the belkin FireWire hub and recap it instead of worrying about the port on the Mac? I do plan to get an external power brick for the belkin as it was sold without one.

 

[ervus]

Most drives like that can be powered externally. If you power the drive separately and it works fine, that would imply a problem with bus power. You could try a shorter wire, or maybe a different wire, or maybe a different power brick for the mini. Is it a 3.5" drive? Some of those were borderline for bus power.

 

[joshjohnson]

Most drives like that can be powered externally. If you power the drive separately and it works fine, that would imply a problem with bus power. You could try a shorter wire, or maybe a different wire, or maybe a different power brick for the mini. Is it a 3.5" drive? Some of those were borderline for bus power.

I have used it with my 2012 Mac mini no problems. The enclosure and drive are 2.5 inch. I have relatively short cables and thick cables for sufficient power delivery. I don’t have another power brick to test but this one says it’s from 2006. I thought it was a 2009 one which would obviously have cleaner power. I can try to replace the brick but I was wondering if anyone knew what the power delivery was like inside the mini itself. If it’s just presenting the raw unfiltered 18v from the power brick, then I need to get another brick. The mini itself works fantastically. I even used it to compile tenfourfox in OS 10.5 and that went without a hitch.

 

[retta283]

I have used it with my 2012 Mac mini no problems. The enclosure and drive are 2.5 inch. I have relatively short cables and thick cables for sufficient power delivery. I don’t have another power brick to test but this one says it’s from 2006. I thought it was a 2009 one which would obviously have cleaner power. I can try to replace the brick but I was wondering if anyone knew what the power delivery was like inside the mini itself. If it’s just presenting the raw unfiltered 18v from the power brick, then I need to get another brick. The mini itself works fantastically. I even used it to compile tenfourfox in OS 10.5 and that went without a hitch.

You may already be aware, but the original G4 Mini had a lower-wattage power supply. It is 85W. Usually this problem would come from using a brick that isn't powerful enough, but there may be some funky stuff happening going in the other direction. Give it a try if you can source an original brick easily. Unfortunately I cannot answer the part about the current used by the system, but recapping is always a good idea on machines from that era if you have the chance to do it.

 

[joshjohnson]

You may already be aware, but the original G4 Mini had a lower-wattage power supply. It is 85W. Usually this problem would come from using a brick that isn't powerful enough, but there may be some funky stuff happening going in the other direction. Give it a try if you can source an original brick easily. Unfortunately I cannot answer the part about the current used by the system, but recapping is always a good idea on machines from that era if you have the chance to do it.

I will likely try to recap it but I was hoping somebody could share the electrolytic values so I could just buy the caps without needing to open and unscrew everything yet again. I’ve already had to take it apart multiple times as it is and I don’t want to crack or stress the plastic more than necessary. I also will have a look at the power brick and again try to get a 2009-ish era replacement for the one I have. I do want to look in to how to take it apart and recap the old bricks though because you can’t keep replacing them forever and i would hate to loose use of such handy little macs just because the power supplies are plastic welded shut.

 

[ervus]

Based on what you've reported it doesn't sound like a power problem, but you could open the drive and check it with a volt meter. I'm pretty sure the mini just passes thru the brick power (18v iirc) so on the drive you should see 18v from the mini converted to 5v for the 2.5" drive. What voltage does it get from the intel contraption?

 

[joshjohnson]

Based on what you've reported it doesn't sound like a power problem, but you could open the drive and check it with a volt meter. I'm pretty sure the mini just passes thru the brick power (18v iirc) so on the drive you should see 18v from the mini converted to 5v for the 2.5" drive. What voltage does it get from the intel contraption?

I don’t know yet but if there is a ripple I’d need an oscilloscope to see it likely. There probobly is thought so I may yet need to replace my power brick. I’ll try to get one from PowerBook medic

 

[joshjohnson]

Can anyone take a clear photo of their G4 mini’s mainboard with the modem removed showing the markings of the electrolytic and tantalum capacitors clearly? All the photos I find on Google image search are either lower resolution then readable or have the glare of the flash reflected in the capacitor cans making them unreadable.

 

[joshjohnson]

Has anyone tried to open the Mac mini 05-09 power supply brick to gain acces and rebuild the internals? It seems something good to do even if you need to put the innards in another casing to prevent electric shocks. We should want to preserve the polycarbonate minis instead of throwing away power bricks until they run out.