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Old 09-10-2020, 01:41 PM   #1
LearningToRepair
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Default How to desolder transformer from PCB?

Hi!

I have difficulties desoldering transformer from PCB. I tried to use solder wick and solder sucking pump. But there is still some solder left that doesnt want to come out from holes. What would be best way to get this thing out? I cant cut it's legs because I only need to temporarily remove in order to be able to access the part that I actually want to replace. I can only heat it and suck solder from bottom side of PCB because on top side there is too little space between transformer and PCB so I cant fit my iron there. I also attach images to show you situation. The transformer is marked with red on both pictures. Any ideas how to get it out without damaging it?

top_side.PNG
bottom_side.PNG
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Old 09-10-2020, 05:55 PM   #2
Spider1211
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Default Re: How to desolder transformer from PCB?

What type of soldering tip are you using? (Conical, chissel,etc). What is the temperature of your iron?

Those components usually suck heat away. Try preheating the board, add flux and use higher iron temperature (with chissel tip ideally) and also a good solder sucker.
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Old 09-11-2020, 04:17 AM   #3
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Default Re: How to desolder transformer from PCB?

I would recommend the following try putting fresh solder back on the board on pins that not all the solder has come out and wait a few second longer before using sucker on the pin you want the solder flowing also use the gravity as your friend also use a temperature controlled hot air gun to preheat the board because multiple layers board can be a pain in the a** to do in the first place

On rare occasion I have used a hot air gun to remove components like this when most of the solder has been removed but if you decide to this use the smallest tip you have to do this
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Old 07-07-2021, 01:30 AM   #4
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Default Re: How to desolder transformer from PCB?

use 2 soldering irons similar to this one .
the best way to remove it without destroying the tracks
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File Type: jpg 61zneipJ-nL._SL1000_.jpg (65.6 KB, 18 views)
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Old 07-07-2021, 03:22 AM   #5
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Default Re: How to desolder transformer from PCB?

Quote:
Originally Posted by thanos01 View Post
use 2 soldering irons similar to this one .
the best way to remove it without destroying the tracks
Where did you get that of soldering iron from please post a website link if you do not mind thanks
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Old 07-07-2021, 03:54 AM   #6
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Default Re: How to desolder transformer from PCB?

Quote:
Originally Posted by sam_sam_sam View Post
Where did you get that of soldering iron from please post a website link if you do not mind thanks
They use them for removing LOCA or using a silicone insert repairing LCDs https://www.aliexpress.com/item/32638881773.html

Far better is one of these https://www.aliexpress.com/item/32800366740.html in an iron with a bit more power and temperature control.
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Old 07-08-2021, 07:42 AM   #7
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Default Re: How to desolder transformer from PCB?

Dilute the lead free solder with Pb solder, then suck that out. Admittedly, those holes look pretty tight, usually transformer holes are a bit larger in relation to the wires. Normally, I'd use my desoldering gun and that would do it, but if I didn't have that, chipquik is always an option.
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Old 08-12-2021, 06:23 AM   #8
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Default Re: How to desolder transformer from PCB?

since the terminals are pretty close (small pitch) I would use this technique:

1. apply flux and then use a generous amount of Pb solder on each pin. Doesn't matter if they short together. In fact I would do this on purpose. The idea is that the new Pb solder will have a lower melting point than the Pb free one. And if you have a big blob of solder on all the pins, melting it all at once will "free" all the pins.

2. Apply flux on the new solder

3. either use a high wattage solder iron with a large chisel tip or use a hot air station to melt the fresh applied solder. Keep the board higher and:

- make use of gravity (the transformer will fall when the pins are free)

or

- try holding it from below (use a tool to avoid burning your fingers !) and carefully pulling down when you notice that the solder has melted.

Make sure to use enough flux. And don't overheat. You could damage the insulation of the wire on your transformer. Go slowly, controlling the temperature by controlling the distance between the nozzle and the PCB.

Works like a charm.
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Old 08-15-2021, 12:45 AM   #9
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Default Re: How to desolder transformer from PCB?

i use pace mbt350 station so i can tell you for pace parts
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Old 08-15-2021, 12:46 AM   #10
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Default Re: How to desolder transformer from PCB?

http://www.waveroomplus.com/Pace-112...-W_p_1559.html

also very useful for dc converters or any rework on big groundplanes
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