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What are your best tips for desoldering chips in plated througholes?

twistedsymphony

twistedsymphony

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When it comes to soldering this seems to be my arch nemesis... nothing wastes more of my time and risks damage to my PCBs than trying to remove larger ICs from plated through holes that have been soldered all the way through. Doing my NES RGB mod and the "bastard" cap on NAOMI are both recent memories of when I struggled with this and I've got a PCB in front of me now where I need to pull 9 40+ pin ICs without damaging the PCB or the IC.

My desoldering gun works fantastic on 85% of the pins but some of them end up being super stubborn or on a ground plane where I can't get enough heat.

Lots of people here do this kind of work so I'm wondering what tips you might have for dealing with this.
 
When I encounter a tricky pin, it helps to actually add solder then hit it again with the desoldering gun. This will help melt any solder on the component side and get a good suck through.

Another tip is to make sure you are using the right size desoldering tip for the application.

If all else fails you can try using a desoldering braid to manually remove excess solder on the parts side, but that's a real pain.
 
I'm definitely using more solder to help get a good seal.

I've seen some people recommend chip quick, though I've never tried that. Anyone have any experience using that for desoldering?


kuze said:
Another tip is to make sure you are using the right size desoldering tip for the application.
Click to expand...
I didn't even think of that; My last desoldering iron had a fixed nozzle so only one size. it looks like there are other sizes available for my new one
 
For the stubborn pins use a pcb holder. Then heat the pin from the component side of the pcb using your normal iron. This melts the solder way better than the desoldering unit. Then use the desoldering gun from the bottom side to suck the solder out. I then wiggle the pin a bit with the desoldering gun to make sure no random solder sticks the pin to the side of the hole.
 
moving to a smaller tip and putting some flux around the joint helped greatly!

I'm using my new Aoyue 2703A+ So far I'm loving it... but yeah definitely need to clean the iron while it's still hot before you shut it down, the first time I used it I didn't clean it and then the second time I used it it had 0 suction and I had to disassemble it to get it fully cleaned out.
 
If your 2703a+ is the same desoldering gun as the 474a++ (it looks like it in the pictures at least), here are some Hakko replacement parts you can use with it. They make really nice upgrades of the stock parts and are readily available/cheap:

Hakko Large Ceramic Filter: A1033
Hakko Small Ceramic Filter: A1009
Hakko Spring Filter: A1030
 
It has taken me years to master the art of removing large DIP package through hole chips from pcbs with large ground planes. Even with an expensive Hakko FM-204 desoldering station, pins connected to large areas of copper (ie; ground) can be trouble!

Therefore we must consider the problem as how to transfer more heat energy when desoldering these trouble pins.

My approach is to use my hot air station and desoldering station in tandem. Typically I set the hot air station around 250C, air speed medium, and pre-heat the general area of the chip from the bottom of the pcb to bring the average temperature up. The idea is not to melt the solder with hot air, but to get the pcb around 100C or so. Then start soldering sucking! Sometimes I will keep adding hot air from 4" away, while desoldering each pin. Give it a try!!

Sometimes I will desolder all pins, but where the pin goes from skinny to wide, on the top side of the pcb, will still have tiny solder fillet that wont let go. Again, I will use hot air but this time around 300C, heating from bottom side, and I will gently, very gently, pull on the part and it will come out once the solder melts.

Tonight or tomorrow I have on the task list a job to remove a dip package mcu from a $1000 gameboard. Will post some pics :)
 
Mitsurugi-w said:
For the stubborn pins use a pcb holder. Then heat the pin from the component side of the pcb using your normal iron. This melts the solder way better than the desoldering unit.
Click to expand...
+1. this is what i did with suspected TTL chips, for rare/custom dip chips, i don't dare to do that. and true, heating the suspected chip from above is faster than heating from solder side.

if not, use both hand solder and hot air blower to assist most of the time will do the job. try to hot air not in the one pin spot, because the spread ground/power plane, heat a slightly larger spot around that pin, moderately, this, many times got me better result than heating just one pin spot. and i do not use electric desoldering gun, just a normal hand solder sucker with additional rubber tip. that rubber tip really help getting clean results.
 
I was working on a Truxton yesterday and it's the first time I've ever not been able to get pins out no matter what I did

I ended up heating the stubborn pins with an iron while slowly removing them and still lost a couple of through holes that I then had to patch :(

Some boards are bastards, you just need to keep adding fresh solder and vacuuming until they come free or as close as you can get to remove them safely then clear the hole afterwards
 
His website lord voultar or his twitter.

In any case I tried contacting him on both shmups/his website/twatter to see if he does nesrgb mods, but radio silence. On his website he has it listed as a service, but its $0.Unless you're suppose to just add it to your cart or wait for it be in stock idk. Kinda unprofessional to read a message and not get a response.
 
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Derick2k said:
Cool, how does one contact this Voultar? I'll send him my Duo RXs to mod. :D
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​I think he may be really booked up right now from what it sounds like. His site and Twatter are the only way that I know to contact him. He said in the video that he's not doing recaps any longer, but you could still run it by him since you'd be getting them RGB modded already.
 
twistedsymphony said:
moving to a smaller tip and putting some flux around the joint helped greatly!

I'm using my new Aoyue 2703A+ So far I'm loving it... but yeah definitely need to clean the iron while it's still hot before you shut it down, the first time I used it I didn't clean it and then the second time I used it it had 0 suction and I had to disassemble it to get it fully cleaned out.
Click to expand...
@Sp33dFr34k
This ;)
 
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