2007 Macbook logic board fault

[tony359]

Good day all,

I got a 2007 MacBook from a friend. The fan was not working so it was overheating.
Once the fan was swapped, I installed an OS and it worked fine.

The board had quite a few corroded spots so I removed it, touched those spots with a soldering iron, washed the board in PCB cleaning fluid (I've done that many times), rinsed it with distilled water, dried it etc.

Unfortunately it doesn't work anymore. It does turn on, fan spins, power LED turns on. But no picture.

If I see that right, I have missed VCORE on L7100 (page 59).
Now, this is the first time I am dealing with an Apple board, the schematics are quite nice and if I see right I have the power sequence on page 3

But before I spend hours on it, is there anything obvious I might be missing? I believe I have reconnected mostly everything, is there something obvious which would prevent the CPU from starting?

If I need to diagnose, is there a way to turn on the board without the keyboard connected? It would be difficult to turn it on if I have a short and fragile keyboard lead to be wired to the board. Also, I believe the board doesn't start without a battery connected - that would also make diagnostic impossible!

Any hint very much appreciated.

Schematics attached - but they're coming from this very forum!
https://www.badcaps.net/forum/troubl...or-an-820-2279

[piernov]

Boards for A1181 are usually pretty robust, shouldn't need to touch them much.
I'd suspect improper drying first, but maybe something got damaged.
ALL_SYS_PWRGD is a good checkpoint as always.
Board should turn on without battery if using correct Magsafe. Not 100% sure if that specific model turns on automatically when Magsafe is attached if there is no main battery pack and no RTC battery connected.
Regardless, it has power-on pads at R5010 to turn it on, as usual shorting SMC_ONOFF_L to ground.

[tony359]

hi - thanks for your help.

I found R712 broken - it was me when I scraped the corrosion it has on top. I thought it was ok but I read kiloohm and it should be 10 ohm. That is the Vin for the controller IC which is driving VCore.
I've got some new on order, fingers crossed.

Thanks so much for the turning on tip. I found the SMC_ONOFF_L online but I wasn't sure I could just short them to ground. ahaha amazing, I've just noticed those pads, they have the "on/off" symbol on it. Fantastic thanks so much.

I'm not sure about turning on without battery. I tried again earlier on and it would not turn on without battery. But once it did. So... puzzled. But hopefully I won't need to do further troubleshooting.

I'll update once R712 is replaced!

[tony359]

The Mac is back to life!!

The 10Ohm resistor I damaged was rusted underneath so maybe it was a good thing I broke it

Once replaced, the macbook came back to life!
Thanks for your help!