Various common A1181 logic board issues
Hi! I came across about a hundred 2.4GHZ A1181 boards. About half of them worked (hooray!) and I've either sold or built those out, but among the bad boards, there are several problems that seem to be common across several boards each, and I was wondering if anyone's had experience with them:
1. Board appears to be functional and starts to boot, but then shuts off within 5-15 seconds of powering on (heatsync is attached)
2. Board powers on and works fine, but does not restart once shut down, unless it has been allowed to sit without power for hours
3. Video displays, but is compressed to a small box in the middle of the screen (I've tried all the resets)
4. Solid amber light, no power (no battery connected)
5. Video shows quickly alternating black and then white screens, almost as if in place of the flashing question mark
6. Inverter light but no video, and no external video (I assume the video chip is fried)
7. No sound
Please keep in mind I'm testing with known-good components, so the answer is not going to be a bad DC-in, bad inverter cable, etc.
Anyway, thanks! If I could figure out any one of these, it would represent a whole pile of boards being fixed. Thanks in advance!
Do you have a reflow oven big enough to hold the entire board or have you thought about investing in one? On the cheap you can use a 30" residential convection oven that goes up to 500*F. But you would have to manually step up and step down your temps unless you made a controller board to do it. Something like that could save you a lot of time over using a smd reflow station. It should repair the ones with bad and cold solder joints, without taking the time to troubleshoot where they are. Might fix some of the ones with video problems also if the BGA on the chips have been compromised instead of the chips being bad.
由 ABCellars 完成的
Wow! I never knew reflow ovens existed, but now I'm considering buying one! Thanks! Are the low-end $200 ones on eBay worth considering? I do have a potentially suitable traditional oven, but like you mentioned the temperature issue could be a problem. Plus I don't know what I'd sit the board on that wouldn't damage it. So, just curious, how long do you "cook" a board? I imagine 2-5 minutes at the high temperature? Thanks again -- this is really insightful stuff!
由 rdklinc 完成的
All the reflow ovens I looked at on eBay for around $200 will only hold about a 7"x9" board. Your traditional oven will not work, unless it is a convection oven. There are no hot or cool spots in a convection oven, because of the fan circulating the air in the oven. Your boards will need to be heated evenly for a number of reasons. Insofar as what to sit the board on I would make a jig that holds the board just like it is held in the notebook. In fact that is a necessity since you don't want your board to flex during the process. If the board flexes during the process you will have done more harm than good. The temperatures must gradually be stepped up and stepped down to prevent flexing of the board and thermal shock to the components. There are a number of good tutorials on the web.
Also think about the manufacturing process.
One reason why I mentioned reflow ovens to you is you have enough of these boards to make learning this art & science worth your while. Again there are great tutorials on the web.
由 ABCellars 完成的
continued.. The manufactures use reflow ovens with a conveyor belt. Usually they build them in steps large or heat absorbing components go on first. Usually the small components that use less solder are put on near the end in a separate process. Plastic parts and electrolytic capacitors will go on last to prevent the problems associated with heating them up. These boards are double sided. More than likely a manufacturer will have used some form of adhesive to hold the components in place on one side of the board to prevent them from falling off while the boards are built. Keep in mind that you can't see the solder balls on a BGA with out some form of x-ray. Those balls are going to have the largest mass of solder on the board. After you have figured out a temperature where the larger components solder "wets" keep it at that temperature for an extra minute to be sure the BGAs have reflowed also. You will more than likely mess up several boards learning the process in a manner that works for you and the boards.
由 ABCellars 完成的
Wow, thanks once again -- great information! White MacBook boards are smaller than 7x9", so a cheap $200 oven may work, at least to start with. You're right, I have so many boards that it would be a shame to not at least give it a shot. I'm currently selling the bad ones for half my buying price, which is reasonable, but if even 2 boards end up working, that would be enough to pay for the oven. I will seek out the tutorials. I suspect it will take several attempts to learn what needs to be removed before "cooking" and what can stay on, but again, if I fry 10 boards, it's not a huge loss. Thanks again! I'm accepting your answer, because you've provided some amazing insights, and have come as close to anyone ever could as far as providing "the answer".
由 rdklinc 完成的