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I'm trying to desolder 4 IGBTs and a diode all connected to a heat sink but it's not going well , I tried adding solder to help melt the old one but it didn't work well, I'm using a 100 watt soldering iron and the pump. How should I do this task? enter image description here

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    \$\begingroup\$ Do you have a hot air gun? You can heat up the whole heat sink with that. That way the iron does not have to deliver that mough energy to heat up the whole block of metal. Adding additional solder sounds like a good way to go, just try heating up everything together. \$\endgroup\$
    – jusaca
    Jul 29, 2019 at 7:09
  • \$\begingroup\$ My hot air gun blown out days ago but I'll try to get another one , thanks for the idea \$\endgroup\$
    – Chebhou
    Jul 29, 2019 at 7:32
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    \$\begingroup\$ Now this might be a bad idea, but I see one guy on youtube, who fixes apple products. He sometimes pre-heats the boards in an oven. (NOT a microwave oven!!! A normal baking oven.) If you want to bring the temperature of the whole board up, so that the soldering iron doesn't spend all its time heating up the sinks, etc, you could try that. Be careful not to burn yourself when the board is hot. \$\endgroup\$
    – Duck Dodgers
    Jul 29, 2019 at 7:47
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    \$\begingroup\$ preheating either with a hot air gun or an oven are the way to go. Basically you need to get the whole assembly t a higher temperature so that the iron has less heat to deliver. \$\endgroup\$
    – danmcb
    Jul 29, 2019 at 9:13
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    \$\begingroup\$ also : do you care about destroying the components? if not - cutting the legs and removing the stubs is usually much easier. Keep the board and sacrifice the silicon. \$\endgroup\$
    – danmcb
    Jul 29, 2019 at 9:14

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Loosen the screw on all components to remove the heatsink first. The heatsink absorbs most of the heat from your soldering iron, making it virtually impossible to desolder the components. If possible try to heat the solder joints with a hot air dryer so that the component can fall out when all the solder joints are warm enough. However, this is not easy without professional equipment.

When the screws are out of reach, it doesn't get any easier. Then you'd have to make sure that the heatsink is getting to the right temperature, which could lead to thermal destruction of the components.

If the components are damaged anyway and are not reused, tweak all pins of all components. Then you can desolder the remaining pins individually from the PCB.

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  • \$\begingroup\$ That's the problem the screws are out of reach, covered by the mosfet driver pcb mounted vertically on the board \$\endgroup\$
    – Chebhou
    Jul 29, 2019 at 7:30
  • \$\begingroup\$ That's the problem the screws are out of reach, covered by the mosfet driver pcb mounted vertically on the board \$\endgroup\$
    – Chebhou
    Jul 29, 2019 at 7:30
  • \$\begingroup\$ @Chebhou: Do you want to reuse the components? \$\endgroup\$
    – Daniel K
    Jul 29, 2019 at 7:48
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    \$\begingroup\$ @Chebhou I have edited my answer. Pinch all the pins and you'll save yourself a lot of pain. \$\endgroup\$
    – Daniel K
    Jul 29, 2019 at 8:26
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    \$\begingroup\$ @Chebhou Please accept my answer if your problem is solved \$\endgroup\$
    – Daniel K
    Jul 29, 2019 at 10:25

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