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Apple Desktops Discussion of Apple's desktop machines including Mac Pro, iMac, Power Mac, and mini

Imac G5 help. Suspect faulty psu?


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djkus

 
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Hi all, bought a 20" G5 Imac with 2gb ram and 1tb hdd off ebay last week. (sold as faulty)
It came today and when you turn it on, it appears to boot.. it will get so far, then go off...
try and boot again and it will go off.
try it a 3rd or 4th time and it comes onto the os and it works and stays on.
turning power off and back on again quickly and it boots again with no probs..

does this sound like a capacitor problem on the logic board or psu ?

Ive yet to open it up to check the capacitors, ill do that later when im back from work.

look forward to your thoughts on this.
By the way, it has no camera on it so perhaps one of the early ones?
It cost me 95 delivered so I think I got it for a good price...
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djkus

 
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Any ideas about the cause of this?
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EvenStranger

 
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It certainly sounds like a possible power supply issue. However, the capacitors on that model both on the logic board and in the power supply are suspect, and until they can be visually inspected for bulging or leakage, it's impossible to say one way or the other. However, that computer only has five major parts - HD, Optical drive, logic board, power supply and display, so it can only be so complex.
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djkus

 
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Hi, thanks for the info.
Ill open it up tonight and check it out, it would be nice to see some bulging caps..
easy and cheap fix.
the fact it powers on after a few goes is good.. least the logic board isnt completely dead.. i think this is good anyway
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djkus

 
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opened up the iMac and on touching the caps to the left of the logic board (above psu) u can feel/see they are slightly raised.
bought a full cap kit off ebay there so will fit that..

i just installed the os and am using it right now! the problem only affects the initial power up.. after a few failed power up sequences it works..
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MacDude121

 
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Yes, it does sound like a capacitor problem all around. I remember a member quite a while back had a similar problem. Only it was with an eMac, also a model that's plagued with the bad capacitors issue.

Hope you can get it working in tip top shape, great buy for 95.
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dtravis7

 
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Is your iMac the one with the Isight Camera or another earlier model? If the caps are bulging at the top, that is probably your issue. My iSight iMac G5 did that and it was a bad power supply cap that was bulging and leaking.
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djkus

 
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it is 1.8ghz with no camera, i think its the original model.
i notice inside there is a space for airport card, there are SO many on ebay, does an airport card from a powerbook or any apple device work on this g5 iMac?
i was given a plus com usb dongle, but I've downloaded and installed drivers to no avail..
ralink sware doesn't see the dongle...
very annoying, so its lan at moment.
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djkus

 
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Update...changed 5 bubbled up caps on logic board..same fault..

Opened up psu and every capacitor on secondary stage of psu was bubbled up.

Replaced all capacitors on psu..
System booted first time...
Was installing leopard and after about 20 mins... Pop.... Pop.. But system still on no problem..

Opened up iMac to see two of the caps on logic board popped and fibre came out of them.

System us still working and boots every time with no other faults..

Do you think I should worry about the popped caps? Think real fault was psu..which seems to be fixed.

Any thoughts would be appreciated.
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dtravis7

 
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I would for sure change those popped caps. It might cause a Kernel Panic or some other issue down the road if you leave it that way.
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+1 for dtravis7 advice. A burst electrolytic capacitor can cause all sorts of havoc if it starts leaking over the board. And one that has burst no longer has the proper capacitance anyway.
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tamaras82

 
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Quote:
Originally Posted by djkus View Post
Update...changed 5 bubbled up caps on logic board..same fault..

Opened up psu and every capacitor on secondary stage of psu was bubbled up.

Replaced all capacitors on psu..
System booted first time...
Was installing leopard and after about 20 mins... Pop.... Pop.. But system still on no problem..

Opened up iMac to see two of the caps on logic board popped and fibre came out of them.

System us still working and boots every time with no other faults..

Do you think I should worry about the popped caps? Think real fault was psu..which seems to be fixed.

Any thoughts would be appreciated.
Hi Djkus, can you please tell me which cap repair kit you bought from ebay?
I'm going to try to repair two imac G5 that I have with bulging capacitors... any good tips would be greatly appreciated!
Best Regards,
Tamara
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