Thanks for all the feedback thus far
It is hard to tell if you are doing something wrong without seeing what you are doing. 500 C is definitely overkill.
When I need to remove a chip like this with a lot of thermal mass on the board, I set 350-400 C and lower air flow. Then basically do what they do in the video. Hold the nozzle close to the IC. Temperature drops very fast with the distance.
You don't need to hold the IC with the tweezers. It is enough to just poke it on the side. Once the solder is melted, it will just move to the solder mask around.
I would also try to find some scrap boards and train on them first. If you have issues removing the chip, then soldering it back is likely to not go smoothly either.
Yeah, I agree with you it's hard to tell what exactly I'm doing from the original post alone. Allow me to elaborate
I do pretty much what you stated, and what they do in all the videos. I set my temperature to 350C at first, and 50% airflow. Then I started applying hot air from a few inches away to the chip area to warm up the board, and then moved the nozzle a few millimeters from the chip and applied heat directly to the chip while moving the nozzle in small circular motions. As you said, I did not hold the chip with tweezers. I held them close by and poked the chip every 10 seconds or so. After about 45 seconds, the chip still would not budge. That's when I started increasing the temperature and kept applying heat a few millimeters away from the IC and moving the nozzle in small circular motions
As for practicing on scrap boards, I have a few that I've been desoldering and soldering various chips on for a week. I've never had an issue removing a chip from them. Quite odd
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I agree, low flow, 350C, keep the nozzle on the chip, plenty of flux.
Yep, that's what I've been doing. One thing to note though is I used white generic flux paste and applied it to the chip with a cotton swab. Reference:
https://www.amazon.com/Delcast-Rosin-Soldering-Flux-Paste/dp/B00SVESNTC/ref=sr_1_2?dchild=1&keywords=delcast+flux&qid=1624762597&sr=8-2However, today I got a soldering shipment in, and now have Chip-Quik Tack Flux. The kind that comes in a syringe. Reference:
https://www.amazon.com/gp/product/B08KJPG3NZ/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1Admittedly, understanding flux is one of my weaker points in soldering knowledge, but I've been getting along until this point by using common sense, and the way my father taught me to solder many years ago. And outside of that, using whatever kind of flux they use in whatever instructions or video I'm attempting to follow
What air gun station do you have? They are not all made equal after all.
After looking at the video, that chip has a big pad. I have never had a problem with my Atten, no matter the size of pad on a chip.
What hot air station are you using?
I think he needs a better hot air station. I never crank up mine that high and I only once needed a preheater but that was an extreme situation. I have seen videos of people unboxing and trying cheap (under 200 dollar) Chinese hot air stations and they were struggling with things my old OKI does in less then 10 seconds.
A good station measures the air so you have the set temp un-depended of the airflow. Cheap stations cool down a lot if you increase the airflow and you have to crank them up by hand to compensate. If so, leave the airflow low, use a IR or TC tempmeter to check what happens on a chip while practicing/experimenting. .
The hot air rework station I'm using is the X-Tronic 6020-PRO-X. Link:
https://xtronicusa.com/products/hot-air-rework-stations-parts/X-Tronic-6020-PRO-X-%E2%80%A2-Platinum-Series-%E2%80%A2-750-Watt-%E2%80%A2-Hot-Air-Rework-Station-%E2%80%A2-3-Temp-Presets-Temp-Calibration-Func-C-F-Func-Auto-Cool-Down-Standby-Mode-Mute-Unmute-Sound-&-Patented-Nozzle-Holder-p278541017I got it because I didn't want to get a cheap no-name $50 one from Amazon, and I love my X-Tronic soldering iron so I thought it would pair nicely with it
500°C did more harm than good than in motherboard.
This temperature damaged pads; lift off pads.
Thanks for the feedback. Yes, I agree, 500C seems a bit excessive
Besides that, you need some experience so practice on some old pcbs first.
Agreed, that's why I have a few that I've been desoldering and soldering various chips on for a week. I've never had an issue removing a chip from them. Quite odd
If it is a multilayer board with ground plane(s), desoldering may be difficult. I would preheat the board from below to 100-120 C, then hit the chip with hot air.
I'm sure it could work, just seems odd that not one person in the half dozen videos I've seen uses a preheater or something to heat the board from below, and yet they always successfully remove the chip 🤔
Yep, in case of a thermal pad I preheat the other side first with hot air, flip the board, and then desolder the IC. Usually I set the hot air station to around 320 - 350 °C for desoldering. For preheating I use the same temperature setting (too lazy to change) but increase the distance to the board.
Yes that could work, again just seems odd no one else doing this repair has used a form of preheating
Agree with what others have said and also want to add use lots of good quality flux!! Makes a world of difference.
As with my reply to Microdoser, I used white generic flux paste and applied it to the chip with a cotton swab. Reference:
https://www.amazon.com/Delcast-Rosin-Soldering-Flux-Paste/dp/B00SVESNTC/ref=sr_1_2?dchild=1&keywords=delcast+flux&qid=1624762597&sr=8-2However, today I got a soldering shipment in, and now have Chip-Quik Tack Flux. The kind that comes in a syringe. Reference:
https://www.amazon.com/gp/product/B08KJPG3NZ/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1Admittedly, understanding flux is one of my weaker points in soldering knowledge, but I've been getting along until this point by using common sense, and the way my father taught me to solder many years ago. And outside of that, using whatever kind of flux they use in whatever instructions or video I'm attempting to follow
When things dont like to come off for me I use 2 hot air guns @ 450C. I work a lot on things still attached to aluminum cases tho. Normal things 350C is good enough.
Unfortunately, I do not have two hot air stations, but that would seem rather excessive in this situation
Sometimes parts are glued to the PCB, but you can see that (red stuff peeping out under resistors and caps)
I definitely don't think it's glued on, as it's never been seen or mentioned in any of the videos