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68k-dude

macrumors newbie
Original poster
Jan 11, 2009
3
0
England
My mac is dead. It has served me well but now it is dead. I fear the mainboard is faulty in someway. If there is an electronics engineer who knows how to fault find these boards I would be greatfull of a list of steps. A circuit diagram and firmware to reflash its rom would be nice. but I boubt weather that is likely. I am very experienced in mainboard repair so no stupid comments please. If I get no joy with this, then it is a dremell and lawless powerpc run on a quad phenom or something for the case.

Technical details to follow if I get a response.

Thanks for reading.

68k-dude
 
The power supply turns on. No white light on the front. The processors don't seem to warm at all. Dimm voltage is present. I'll strip it down and run it outside the case to get at more measuring places. The cpu core resistances are 10 ohms, sounds ok to me. What voltage feeds the core regulators on these boards? Is it 5V or 12V? Doesn't matter I'll find out soon enough. What normally dies on these boards? Is it a regulator circuit or is it a bga? if it is a bga then I'm stuffed. Unless it's a dry joint under one of them. Maybe the firmware is corrupt. I wish I had a working board I could utilise during testing it is so much easier to compare. Reading out the firmware would also be nice. By the way, does anyone know if there was a firmware release for this model "A1047" it is an early agp dual cpu?

I'm rambling now, sorry about that.
 
I've got the thing in pieces now. I have measured voltages on the top and a good list of locations and values will follow unless there are any objections from some important people. I need to devise a way of keeping the processors in when they are upside down. Then I can measure the bottom. There are all sorts of interesting things to be found there. The clock gen more regulators and the firmware rom. I'll fire up my scope and check them out tomorrow. It's time to google for some data sheets.

Ps. I've had a go at a signature and a picture thing. I'm new to forums. So if they look stupid I apologise now.
 
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