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  • Author Author: modalpdx
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No more paper stencils

modalpdx

I royally botched a GoodFET build today, and at least some of the blame rests with the silly paper solder stencil that I made (shush, it was glossy and it should have worked better. Who doesn't want to save a buck?) I figured it was worth a shot. One fried MSP430 later (I had to use my hot air gun thingamajig to get it off and realign it, and I suspect I cooked its guts in the process) I'm back at square one and I still don't have a GoodFET. Argh?

 

That which does not kill us makes us...something.

 

Oh well. I just ordered replacement chips through Newark/Element14 so round 2 is coming.

 

UPDATE, 6/13: I have replaced the MSP430 2618 chip (torched by my heat gun during Round 1) with a less expensive 2418. This time, I hand-soldered it. No complaints or errors so far. Two things worth noting for others that my be considering building a GoodFET: the 2418 chip seems to be a drop-in replacement for the 2618 (fingers are crossed that the Internet has not let me down on this bit of information) and the monitor self-test ("goodfet.monitor test" at a command prompt) takes a really long time. Don't kill it thinking it's frozen or in an infinite loop, both of which are probably not true.

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  • How about a picture - I can't see why you would need a stencil (good or bad) to hand solder a TQFP package at all. What package is your MSP430 in and how do you normally solder them ?

     

    MK

  • in reply to michaelkellett

    I'm actually hotplate-reflowing, not hand-soldering. I have a kitchen single-burner (1000W) with a 1/4"x6"x6" MIC-6 aluminum plate that I sit on the heating coil and I use a Harbor Freight router speed control to dial in the heat level. Works like a charm.

     

    I've hand soldered chips like this MSP430 in the past (QFP 64) with minimal fuss. If I didn't want to experiment with paper stencils in general, I would have just done the entire build by hand with an iron. There aren't many parts, although other than the chips they are all 0603 which is smaller than I like to hand-solder. After a point, it just gets unpleasant.

     

    Anyway, here's the GoodFET with parts placed but before reflowing on the hotplate. Next time, hand-solder or use less paste.

    image

     

    And, the paper stencil over the GoodFET before applying paste.

    image

  • in reply to modalpdx

    Hello Erik, Thanks for the info.

    How did you make the stencil ?

    I sometimes blob the solder paste on with an el-cheapo Chinese (via Aliexpress) solder paste dispenser and hotplate reflow. Ages ago I bought  a cheap BGA IR machine which I've just started to use - I'll post something when I have  a bit more to report.

    I'm happy with 0603 and I'll do 0402 if I have to (need microscope for them) for hand soldering with an iron.

     

    MK

  • in reply to michaelkellett

    And I just struggle with headers smaller than normal. WOWimage

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