Tips for removing stubborn big PLCC chips with hot air ?

[smrieck511]

I'm trying to remove the GLU from a IICX board without damaging it. Currently "practicing" on the NUCHIP which I don't need. Removed as much solder as I could with wick and put plenty of flux on the pins.

Then attempted to remove the NUCHIP with hot air using all the technique I'm familiar with. Unbelievably stubborn and my temperature is too high to begin with. I don't have the heart to punish what seems like a good un-corroded GLU chip this way.

Any veterans have advice on the safest way to get these big chips off the board? Thanks in advance.

 

[finkmac]

why not make a single project thread for this se/30 board? would make things more organized

anyways. lots of flux and fresh solder

i apply lots of flux paste to the legs. then reflow all the legs. then I use my hot air station in a circular motion, aiming at the legs.
i poke the PLCC with tweezers ever so often to see if it moves. when it starts moving I grab it with the tweezers... I keep applying air until it comes off the board.

 

[smrieck511]

why not make a single project thread for this se/30 board? would make things more organized

anyways. lots of flux and fresh solder

i apply lots of flux paste to the legs. then reflow all the legs. then I use my hot air station in a circular motion, aiming at the legs.
i poke the PLCC with tweezers ever so often to see if it moves. when it starts moving I grab it with the tweezers... I keep applying air until it comes off the board.

thanks. Yeah I should make it all one thread going forward. What temperature do you typically use?

 

[obsolete]

Preheat the board so your hot air station doesn't have to work so hard. This will also reduce how much you warp the board from uneven heating.

You can also buy nozzles for specific chip packages that direct the heat evenly toward the pins so you don't have to keep swirling the gun around. They aren't necessary, but they help: https://www.sra-solder.com/soldering-equipment-1/nozzles-1877

 

[smrieck511]

thanks yeah this is a donor board that's been bombed. Beyond repair I think so I'm not too worried about it warping. What temperature are you typically using?

 

[iantm]

This is great advice thank you. Just got a hot air gun and want to try removing some chips from a bombed SE board for practice.

 

[SpocksBeer]

Chip quik

 

[smrieck511]

Got the GLU off. Not without a fight and too much heat. One thing I realized, in the case of a badly battery bombed board where you know you're not gonna want the board, after the solder has at least weakened significantly, you can pry the chip up from the corners with tweezers which will take some of the pads off the board. But it actually may be less stressful (less extended heat) on the chip you're trying to extract. The pads will lift well before there's enough pressure to damage any of the pins on the chip. That is my theory at least. Then you can simply clean the torn pads off the chip. Certainly a try that at your own risk kind of thing but it seemed to work for me. This is only necessary in the case of the very large chips. The smaller ones come off easily with hot air. If you think that's crazy and/or stupid, you might be right but it worked for me yesterday at least. Only do this with an unredeemable board of course.

As a test, I just ripped the NUCHIP off a IICX board with absolutely no heat. Just put curved tweezers underneath the corner and pryed it up. Came off with no pin damage and ripped a bunch of pads. Zero heat. Again not recommending this as a procedure. Just doing it for science.

This should get me permanently banned.

 

[herd]

As others have mentioned, warming everything helps and one of those board pre-heaters would be the "pro-tip." I would put more heat into the part you don't care about. i.e. if you want the chip, heat the board, and if you want the board, heat the chip. If the board is definitely scrap, you could cut the chip out. Sometimes making partial cuts around the chip will disconnect the copper planes in the PCB enough that they don't suck heat out too fast. Then you can heat the PCB from the back to stress the chip less. I've seen some plastic chips like that popcorn. Good luck with the project!

 

[smrieck511]

As others have mentioned, warming everything helps and one of those board pre-heaters would be the "pro-tip." I would put more heat into the part you don't care about. i.e. if you want the chip, heat the board, and if you want the board, heat the chip. If the board is definitely scrap, you could cut the chip out. Sometimes making partial cuts around the chip will disconnect the copper planes in the PCB enough that they don't suck heat out too fast. Then you can heat the PCB from the back to stress the chip less. I've seen some plastic chips like that popcorn. Good luck with the project!

good point I was literally going to get a hacksaw blade and carefully cut the chips out. I was wondering about cutting traces to ground if that would have much affect. Makes sense.