Main Microsoldering Soldering 0201 SMD

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  • #56427
    TadejMihelic
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      Hello Alex (and all other users and fans) 🙂

      I just got DELL XPS laptop to repair. Model with USB-C charging ports (motherboard LA-F211P).
      The owner has damaged both USB-C ports intended for power supply. He then bought two new USB-C connectors and wanted to replace them himself. He quickly realized that he would not be able to replace those ports himself, so he took the computer to a repair shop. There, they found that both ports were “ripped off” from the PCB, along with some hole-rings and pads. Instead of the safest procedure with low-melt solder and a hot gun, they only used hot gun to remove the residue. They only soldered one connector and the computer did not power on. Then they brought it to me.
      I looked at the motherboard under a microscope and I found there real mess: missing components, damaged and missing ESD Protection Diodes, burnt ring-holes, … etc.
      I ordered new connectors and a new ESD Protection Diodes (ESD8011MUT5G). I fixed the contacts and soldered both connectors

      But the problem are ESD Protection Diodes … 0201 SMD. Has anyone successfully soldered them yet? What is the procedure? Soldering paste Type 5 and hot gun? Or something else? Thanks for any advice !!!

      Regardless of the damaged ESD Protection Diodes, according to the scheme, the computer should power on. However, it does not start. I checked the mosfets, capacitors, possible shorts, but everything looks OK.
      I found that +5V comes from the power supply through mosfet, to USB-C IC and then nowhere else. I looked at the PCB with a thermal camera and found the USB-C IC Controller is probably bad? (CYPD5225-96BZXI) Does anyone have experience with this?

      Thanks for your help!
      Greetings from Slovenia 🙂
      Tadej

      #58951
      abrsvcs
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        I have used the “hot” tweezers from Hakko with success for small components like this. It does take a little practice though. Take a donor board with this size component and remove/reinstall them until you get proficient. The Hakko FM2023 has a small tip that works well.

        Dan

        #60911
        TadejMihelic
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          Thanks, Dan!

          But I don’t think I can use hot tweezers to solder exactly those components? The problem I see is because those ESD8011MUT5G have “contacts” below and not on the sides… Or I’m wrong? (Please look at the photo I attached).

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          #61388
          Marc Lewis
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            You might try cleaning off all the lead-free from the contact points with a good wick. Then “dope” the points with a good 62/36/2 (silver alloy) solder (MULTICORE DLMP22) that melts at 170°C (338°F). Follow with good flux like Amtech NC-559-V2-TF. Hold the diode in place and heat with low-flow hot air of about 295-315°C(563-599°F). It doesn’t usually take long for good reflow, depending of course on how thick the copper on the board is. Miniature ceramic tweezers are very helpful for this. Let me know how it goes!


            All the best,
            Marc

            • This reply was modified 2 weeks, 5 days ago by Marc Lewis.
            #62028
            TadejMihelic
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              Thank you, Marc!
              I’ll try. I usually use Felder ISO-Core”RA” (60/39/1 – melting point at 183°C – 190°C) and ISO-Core”EL” (60/40 – melting point 183°C – 238°C). But I can order Multicore DLMP22 if this will be better?

              In the technical datasheet of those diodes I found that soldering is possible up to 260°C for max 10 seconds. What about soldering paste f.e. Type 5, with lower melting point? I don’t have it, I’m just thinking…. 🙂

              #62668
              Marc Lewis
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                TadejMihelic: I’m not familiar with that alloy at all and I haven’t gotten around to learing solder paste yet. The Multicore DLP solder melts a bit lower than the Felder from what you’re telling me.I’d go for that one if you can get it. And it’s got a higher silver content which improves conductivity somewhat. Keep in mind that 63/37 and its variants like 62/36/2 are eutectic alloys unlike 60/40. Since the diodes have an upper temperature limit of 260°C, you’ll obviously need to limit the hot-air termperature to close to that; maybe 250-255°C. The tweezer holding the diode will help protect it. I’ve been soldering for *many* *many* years and the new microsoldering techniques I’m learning as I go are interesting. Particularly with using tools like a board pre-heater and really tiny soldering tips coupled with the microscope. It’s fascinating. Some of the factory soldering I see on some of the boards I work on, done by whatever mass production technique they’re using is at times atrocious. Then there’s the boards that all the components are glued down before being mass-soldered. Makes service really difficult!

                Good luck with the diode replacement – let me know how you’ve made out with it.


                All the best,
                Marc

                • This reply was modified 2 weeks, 4 days ago by Marc Lewis.
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