I forgot to add, my soldering station was set to 590 degrees Fahrenheit, for both desoldering and resoldering the new battery. I taped down the new battery cable with a very small triangle of tape prior to soldering — align it; tape it in place, put a little solder on your tip and just touch. It melts right through the hole, and bonds. Then remove the tape and solder the other two terminals (then I also remelted the first one). I would not want to do this job without a 1X-3X microscope! Always let the board cool completely between terminals as the guide suggests. There is a reason surface mount work is almost exclusively done by machines or with hot air and skilled technicians.
Don’t apply any upward force to a SMT pad, ever! If it doesn’t release on 1st attempt, don’t continue heating. Let it cool and try again in 10 minutes. Most components and pads are rated for only 5 seconds of melt temp. (and very little force). Cut off the dead battery and detach adhesive so you can feel what you’re doing.
I agree with several other contributors here, that a properly sized flat screwdriver *that is not worn* held at the correct angle is a better option than a phillips because the screw head is filled in with adhesive tape. BEWARE: The screws on the top and bottom outer edges are not parallel to the case. They are offset by 25 or 30 degrees, with the tips of the screws pointing out towards the outer edge of the case with respect to where the heads are. Use something to get magnification so you can really see how your screwdriver fits, and whether it’s engaged. An undamaged and properly sized standard screwdriver held in the appropriate orientation will readily remove the top and bottom side screws without stripping and with very little force. Feel for engagement — press the screwdriver in just enough to get past the adhesive. Not much torque or pressure is required — just a good fit. You must have the right tools to do this job successfully, and look under high magnification. Align your screwdriver!
I used scissors to very quickly cut the ribbon cable off close to the battery so it’s not in the way. Work under a microscope if you have one — I taped the logic board down with black electrical tape so it stays centered in the field and is easier to work with. Note that there is adhesive on this cable (at the top in the above photo) which should be carefully pried loose before desoldering. I used tweezers to grip the ribbon cable, one terminal at a time while heating with the soldering tip. Without the battery hanging there, you have a good feel for how much pressure is being applied. It was very clear when it was melted loose (comes off with no resistance and no prying, which leaves the pads intact) because there’s no heavy battery hanging on in the way nor adhesive working against you. This also avoids the possibility of shorts electrically damaging the logic board.
Instead of pulling it out, I found it easier to use the display hole to push on the top part of the battery straight down toward the bottom of the unit. This gives you far greater control of the battery/mainboard removal operation; you can push it out (down) in tiny increments and confirm no cables are caught as you do it. Pulling can cause a sudden, catastrophic release and if something is caught, it’s destroyed.
Pay heed to the word “peel”. Don’t pry. Work the tool slowly under the connector, keeping it as close to the board as possible. Don’t pry. The unit I repaired also had a small piece of Kapton tape, the corner of which can be lifted with tweezers.
As commenter Brian Campbell wrote on the previous step, it is important to hold down the white cable socket while carefully working the cable loose from the adhesive. Even a small amount of upward force on the display data cable while it is still inside the socket could be enough to tear the socket off the board. Try not to pry up - use a thin, new (undamaged) opening tool to get under the ribbon cable and keep it parallel and as close to the metal plate as possible. It needs to be worked *under* the data cable, not to pry, as the cable just slides straight out the bottom of the white socket.
If a screw is stripped, you need to somehow get another under the head to apply pressure to unscrew it (while unscrewing it). It’s an unpleasant operation where you have to apply pressure to keep the screwdriver pressed into the head while prying outward so the threads back out. Try not to strip the head, and try not to strip the threads, while helping the threads to catch.
If this happens, you’ll need to replace the screw. It’s not a good idea to reinstall a stripped screw.
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