---------- Original message ---------- Subject: Re: Power Mac G5: how to repair a broken PSU? Date: Freitag 21 Mai 2010N From: Clark Martin <[email protected]> To: [email protected]
> That would be a CAPACITOR. The old name for them is CONDENSER. If you > had a CONDENSATOR in the power supply that would be a problem, it is > something that condenses water out of the air. Yes, I feel ashamed… Sorry for that mistake. In the German language a capacitor is called „Kondensator“, thus I used the wrong vocabulary. That's no excuse, but an explanation. > > If a condensator actually did blow up, shouldn't it be a visible defect? > > It won't always be visible. Sometimes the blow out occurs on the side > next to the PC board so it is hard to see. I took the whole thing apart. I removed the logicboard and didn't find any signs of dust, smoke, brown remains of something blown up or anything. Also, all capacitors look like new from the outside. That is, on the upside and on the (when installed not visible) backside of the logicboard. I also opened up the PSU. The upside also looks as if nothing was wrong with any of the electric/electronic parts. The only detail that discovers it's a used PSU is the obvious dust here and there. I didn't look at the backside yet. > You can try removing each capacitor in turn and visually inspect it. > Then try replacing any that look bad. IF you have a good source they > won't cost you that much but getting a replacement that fits may be > difficult. A friend of mine has a good source for capacitors and will help me with this. I will start with the PSU and hope that the logicboard is not affected. > It's possible to test them but as you stated elsewhere you don't know > how to use a multimeter so testing caps is not really an option. I haven't spoken to my friend yet but I hope he will show me how to use the multimeter. Actually I have such a thing at home, but I don't want to break anything so I don't use it very often. Only to test batteries. I heard that using it the wrong way can break electonic parts for good. > If it came from other than the PSU or logic board you can just > disconnect everything but the PSU and start button from the logic board > and try it. You can't do anything but you can see if it starts up. > > But the BANG implies it is the PSU or perhaps the logic board. Since I don't hear this click sound anymore when I plug in the G5 my guess is that it has to be the PSU. I only hope that the logicboard came away undamaged. > Many switching power supplies can be destroyed by operating without a > sufficient load so don't try testing the PSU without the logic board > attached. That IS a difficult task – to attach the logic board out in the open, just to test the (also open) PSU. But it's good to know that there are “normal” and “switching” PSUs. > Switching power supplies are difficult to test as there are many > components whose failure can cause the PS to not function in exactly the > same way. Also there is high voltage in there and you don't want to > mess with that if you don't know what you are doing. I trust my friends knowledge and experience with that. I know that he would be able to handle this, but I don't know how this “putting load on it” thing will work – the easy way. I don't want things to become more complicated than necessary. Shouldn't it be possible to take power off the PSU – aka put load on it – without the logicboard? Also it would help tremendously if I knew how to switch it on _without_ the power button. There must be some kind of electrical trigger, right? > Look on e-Bay for either a PSU or a G5 , particularly one with a logic > board problem but a good PSU. I did. The last two months. No luck. Most G5s that are sold as “not working” are older models, i.e. up until “Early 2009” Power Macs. The “Late 2005” is the rarest and hard to find, even working ones. Working units are very expensive if I only require them as spare parts depository. > Make sure the supply matches your computer. I don't know if the G5 has > different incompatible power supplies or not but if it does you don't > want to make matters worse with the wrong unit. For the “Late 2005” gladly there are only two: the 710 Watts and the 1000 Watts PSU. They are manufactured either from Delta Electonics or from AcBel. Anyway, thanks for your help. Especially the information about switching power supplies and that I need to put the correct load on it to check it out was very useful. I still hope that my friend will take a close look at it and find the broken part to replace it. That will be much cheaper than getting a new… ahem, a used replacement that could eventually break as well at any time – just like mine did. Thanks, Andreas aka Mac User #330250 -- You received this message because you are a member of G-Group, a group for those using G3, G4, and G5 desktop Macs - with a particular focus on Power Macs. The list FAQ is at http://lowendmac.com/lists/g-list.shtml and our netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml To post to this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/g3-5-list
