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Wanted: Scrap QFP and leadless chips, bad PC board prototypes

Discussion in 'Embedded' started by larwe, Feb 4, 2005.

  1. larwe

    larwe Guest

    I'm trying to test a homebrewed IR-reflow solder controller. Basically,
    this is an add-on that gets hacked into a consumer toaster oven. It
    uses a temperature sensor aimed at the bread^H^H^H^H^Hboard tray to
    determine the approximate surface temp, and a microcontroller to handle
    the heater PWMing and profile timing. You enter the soldering profile
    on a keypad, hit "start" and walk away - in theory.

    However, I've run out of unwanted boards and chips. I'd be interested
    in acquiring any unwanted, non-functional *cheap* devices and scrap
    PCBs that have appropriate land patterns on them. I'm mainly interested
    in TSOP, TSSOP, TQFP/PQFP/MQUAD (44 through 208 pins), but I'm also
    curious about MELF and similar packages.

    I'd prefer unstuffed PCBs but can deal with desoldering and cleaning if
    I have to. FR4 is the only material I'm attempting to qualify.

    Although I don't intend to use this on BGA packages, I'd also be
    moderately curious to test the controller on BGAs if there are
    devices/PCBs available. (I have access to X-ray facilities to check the

    If you have suitable scrap materials for sale, please email me!
    larwe, Feb 4, 2005
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  2. Hi,

    If this is just for a hobby project you don't really need a controller.
    I'm pretty happy with the results that I got using an $18 toaster oven
    and a melting temperature indicator:


    True, you may get more consistent results with a temperature controller
    but I think other factors like, for example, the solder paste
    application process, also influence the quality of the final result.

    If you are willing to spend some money, this company sells test PCBs and
    dummy ICs (i.e., packages with no silicon inside):


    -- Georgi

    -- Georgi
    Georgi Beloev, Feb 4, 2005
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  3. larwe

    larwe Guest


    This is for two purposes: 1) assembling protos for customers with less
    work than hand-assembly and less expense than contract assembly, and 2)
    because it's a fun project :)
    Yes, I've read your page. This method doesn't allow one to reach even
    approximately the right profile, though. In particular the cooling
    phase must be controlled. For example with this method I have cracked
    ceramic packages and often created dull joints by cooling too fast.
    Conversely, cooling too slow affects longevity.

    I'm basically looking for someone who has scrap parts and/or boards for
    sale, so that I can do some more inexpensive testing. Each board can be
    used 2-3 times for tests (though only the first test is really
    larwe, Feb 4, 2005
  4. larwe

    jlochner Guest

    Nice project:

    Sorry I have no boards or components to contribute but what are the
    details of the project?

    uC, IR sensor, etc.
    jlochner, Feb 6, 2005
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