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Propeller Quickstart Board is excellent — Parallax Forums

Propeller Quickstart Board is excellent

obrienmobrienm Posts: 65
edited 2012-01-08 23:03 in Propeller 1
Parallel Processing Enthusiasts,
I have to say that the new Parallax Propeller Quickstart board is an excellent piece of engineering. It has just the right amount of features needed to avoid both breadboards and custom soldering because of the 8 included LEDs and the 40 pin header - It is at the sweet spot for usability, competitive advantage and volume pricing. Parallax has really outdone themselves by providing the option of powering the board via USB. I can get 7 quickstart boards running full speed at around 0.15A per board without adding a powered hub. With a powered hub 16 boards run fine via Propellent.

My question is about modifying the board via a single solder fix. I would like to move the power LED's as indicated in the included photo on the right. I do not have experience with surface mount - I have soldered through-hole. Before I touch the board, can I use a regular soldering iron on the two pads for a couple seconds to move the LED or should I use a toaster oven (hopefully not). I am assuming that there is nothing different between surface mount soldering except for doing it under a microscope.
The picture is of two quickstart boards side by side - the one on the right will be modified, the one on the left is a reference.



thank you in advance
/michael
qs_power_led_offset_before.jpg
1024 x 734 - 68K

Comments

  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2012-01-08 10:12
    Just use a fine-tipped soldering iron -- definitely not a toaster oven. Since the Spinneret is lead-free, the solder will have a higher melting point than what you're used to. I would touch the tip of a hot, well-tinned iron to the corner of the pad. If the solder does not melt right away, add a little leaded solder to the iron/pad interface. Once the solder melts, lift off the LED with tweezers.

    To resolder it do this:
    1. Tin both pads with leaded solder.
    2. Using solder wick, remove the solder from one of them.
    3. With tweezers hold the LED against both pads, and melt the solder on the pad that still has solder.
    4. Press the LED flat onto both pads, and let the solder cool.
    5. Solder the LED to the remaining pad.
    6. Go back to the first pad, if necessary, and touch it up with a little fresh solder.

    -Phil
  • Cluso99Cluso99 Posts: 18,069
    edited 2012-01-08 15:14
    The one on the right can be removed quite simply by just heating the pad while gently lifting the LED with tweezers. As soon as the solder melts the LED will lift off.

    Be careful with LEDs as they (were some years ago) more fragile than normal ICs heatwise. So apply the heat for as short a time as possible.
  • jmgjmg Posts: 15,183
    edited 2012-01-08 16:52
    obrienm wrote: »
    Before I touch the board, can I use a regular soldering iron on the two pads for a couple seconds to move the LED or should I use a toaster oven (hopefully not).

    The ideal is to heat BOTH pads at the same time, and avoid 'dancing the tip' - that means either the two-barreled Tweezer style Soldering irons, such as
    http://shop.vetcosurplus.com/catalog/images/XY-TWZ60-1.jpg

    or making a simple heat-header from anything heavy enough : heavy copper wire or copper sheet.
    Hot-air blower.irons are also ideal for this, but they are not cheap.
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2012-01-08 17:03
    Did I misunderstand the OP's intention? I initially assumed that he had received a poorly-soldered LED (the one on the right) that he wanted to repair to make it like the one on the left. If that's the case he does not have to heat both pads to remove the LED, since it's stuck to only one of them.

    -Phil
  • RaymanRayman Posts: 14,849
    edited 2012-01-08 17:45
    You can modify it with a soldering iron just fine. But, wouldn't you like a plug-in board that did the same as you have in line?
  • jmgjmg Posts: 15,183
    edited 2012-01-08 21:26
    Phil Pilgrim (PhiPi) wrote: »
    Did I misunderstand the OP's intention? I initially assumed that he had received a poorly-soldered LED (the one on the right) that he wanted to repair to make it like the one on the left. If that's the case he does not have to heat both pads to remove the LED, since it's stuck to only one of them.

    -Phil

    Hard to be sure..

    When he said ["move the power LED's"] (plural) I figured he intended to change many boards, because of some alignment issue (My guess was swap the R and Series LEDs ?, or even move the LED to a CUT-trace somewhere else... )

    Besides, Parallax would not really ship a board with a skewed power LED, would they ? ;)
  • obrienmobrienm Posts: 65
    edited 2012-01-08 23:03
    Everyone,
    Very good details, appreciated, i will post an after photo shortly. This post is indirectly directed at the QC or VE dept - that i have the highest respect for. My 1st batch of 18 boards are all unmodified and function beautifully. Power indication is undefined in one case but does not affect functionality. Aside: What should we do with all of these very nice artworked cardboard boxes

    /michael
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