Replaced logic board, still doesn't work

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Level 1

4 points

Replaced logic board, still doesn't work

I replaced the logic board on my imac g5, and it doesn't power on. It's possible the replacement logic board was also bad, but if it wasn't, is it possible there's something else that could be bad, or something else I should do post replacement but prior to powering it on?

If i can't get the board to work, will it be possible to get data off the hard disk from another machine? It sounds like target mode requires being able to power the target machine on...

iMac, Mac OS X (10.5.8)

Posted on Jan 23, 2015 11:15 PM

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Answer 1

a brody

Level 10

82,941 points

Jan 24, 2015 12:04 PM in response to jake_blues

You can get data to another Mac, but unless it is of a certain format you may not be able to read it.

Note, starting with Mac OS X 10.7, PowerPC applications were no longer supported as this tip explains:

http://discussions.apple.com/docs/DOC-6271

You should make sure the PRAM battery, a coin shaped battery is current, that the Airport card if present is an Extreme and its antenna is hooked up, that the hard drive temperature sensor is hooked up, and there are no bad capacitors. You can tell the bad capacitors apart either through bulging, leaking.

http://www.instructables.com/id/Imac-G5-DIY-capacitors-repair/

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Answer 2

rccharles

Level 6

12,957 points

Jan 24, 2015 12:11 PM in response to jake_blues

You can always remove the hd and use an external adapter. Call owc and verify that it will work with your drive.

http://eshop.macsales.com/item/NewerTech/U3NVSPATA/

These machines had lots of problems. Capacitors in power supply can fail. I'd look at them and see if bad. Shouldn't be too hard to replace.

G5 has these hardware issues:

-- bad capacitors on logic board

-- bad capacitors in power supply

-- badly soldered video chip

-- "There were several Mac models with flat panel displays that had bad displays.

Most had serial numbers beginning with "W8"---the code for one specific factory.

This affected PowerBooks as well. If that's the case, the rest of the computer

is probably fine." by Allan Jones in

https://discussions.apple.com/thread/4922592?answerId=21630224022#21630224022

Google: g5 capacitor replacement kit

More info on capacitor replacement kits

http://jimwarholic.com/2008/07/how-to-repair-apple-imac-g5.php

http://thecapking.com/applg5.html

A success story:

https://discussions.apple.com/thread/5240737?answerId=22751906022#22751906022

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Answer 3

jake_blues Author

Level 1

4 points

Jan 25, 2015 3:37 PM in response to rccharles

THanks, that was super helpful!

Just to clarify, when I connect the power cable, LED1 on the logic board does light up; does that mean the power supply is ok, or could the light still come on even if there was a bad cap in the supply?

Thanks again!

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Answer 4

jake_blues Author

Level 1

4 points

Feb 9, 2015 4:28 PM in response to jake_blues

ok, I'm on my second replacement logic board and still the thing doesn't power on. Again, Led1 comes on so it seems to be getting power, so i think the power supply is cool. Is there anything else that could be bad that could cause the thing not to come on? it's possible i've gotten two bad logic boards but they were from two different sellers, both of whom indicated that they were working.

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