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You are here: MacNN Forums > Hardware - Troubleshooting and Discussion > Mac Desktops > What is this - g3 mod

What is this - g3 mod
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lgordnier
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Join Date: Mar 2009
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Mar 9, 2009, 10:42 AM
 
so I work on macs most of the day here. I've worked on many obsolete and dying machines. Many of them come from old companies that definately had some hardware geniuses working their computer department. And I've recently came across this hardware modification that's just twitching a nerve. I need to know what this does.



This machine *seems* to function normally. I can't find any details about the chip that it's soldered to on the other side of the board, I can't find any info on the hardware manager *same as any other 500MHz iMac*.


*this is the other side of the LB, IC in middle of picture is what is soldered to on the other pic*

If you've seen this mod before, PLEASE let me know what's going on here.
     
Simon
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Mar 9, 2009, 11:06 AM
 
The chip is 8x1Mbit flash memory.
     
sideus
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Join Date: Feb 2002
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Mar 9, 2009, 11:54 AM
 
Looks like the MLB had a defect and it was repaired. I've seen this on refurbished iMac logic boards from Apple.
     
ibook_steve
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Mar 9, 2009, 10:11 PM
 
The flash memory is not a through-hole device. That rework wire is not necessarily connected to the flash, only the pads on that side of the board which may connect to vias that go to the other side of the board and connect to the flash. Those two rows of pads are for a "nostuff" chip or connector that may be nostuffed because of this particular configuration or for a test connector not needed for production. The wire looks like it's going to a resistor as a pullup, but there's no way to know.

If indeed it is going to the flash (have you tried ohming it out with a multimeter?), you can figure out which pin it is and look up the spec sheet on line. It could be going to a flash write enable signal to enable writing code to the flash that normally would not be necessary. There's no way for me to know for sure without checking it out.

Steve
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