Solder won’t melt on MacBook 2021 logic board – need advice

[defdjamel]

Hi everyone,
I’m trying to remove a component from a 2021 MacBook logic board, but I’m having trouble.
https://www.electronicsdatasheets.co...s/tlv70733pdqn
I’m using hot air at 480 °C with full airflow and good flux, but the solder paste is not melting.

I know there’s a lot of thermal dissipation from the board, and I suspect the copper planes are absorbing most of the heat.

Do you have any tips for this kind of board? Would a preheater help?

Thanks in advance!

[sam_sam_sam]

You need to preheat the board around the device that you want to remove and then use the hot air gun
If you have a toaster oven set the temperature 300*F or lower all that you are interested in is preheating the board so the heat does not escape to the rest of the board but used an infrared thermometer to measure the temperature do not go by the oven temperature settings because most of the time they are not accurate

Now you might want to remove the compartment that might be damaged by heat first

Or use two hot air guns one on top of the board and one on the bottom and put aluminum shielding on the components that could be damaged by heat

[petehall347]

add leaded solder if possible

[CapLeaker]

Preheater and good flux, that’s all you need.

[reformatt]

If you still have the CPU heatsink on, that will absorb most of your heat if the area you are working on is near the CPU. Another factor to consider is your nozzle size. For most rework of passives and small IC's, I use a 6mm nozzle. I use bigger for larger IC's like SMC's or RAM. Remember that your hot air is really heating up the board not the component per se. So having a larger surface area from your nozzle is the key and the distance from nozzle to board is also a factor. It comes down to the nuances of your station and practicing to see where the sweet spots are. I use 460 degrees C at 50 air flow on my Quick TR1300A with a 6mm nozzle for most MAC rework. PC boards don't have all the ground planes that the MAC's do, but I only drop the temps like 10 or 20 degrees for those.

Also if you have a cheap air station, then you should look at using a thermocouple to measure what it's actually producing. Most stations have a means of calibrating the display temperate vs what is actually coming out.

[defdjamel]

Thank you for your answers.

The problem was that I was using a small nozzle (5 mm) on my hot air blower. I replaced it with a 10 mm one, and now it works.

I’ve understood that you don’t really heat the component itself but rather the PCB because of heat dissipation.

Now it’s easy to desolder a CD3217… ✅