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BS2 - Fixed! — Parallax Forums

BS2 - Fixed!

PJAllenPJAllen BannedPosts: 5,065
edited 2010-09-17 11:45 in BASIC Stamp
I fragged one of my Stamps, I stuffed an output (ouch) while doing some "mythbusting."
I ordered a replacement interpreter/PIC.

SSOP ain't too bad.

Here's how I did it:
1) I gooped up the IC pins with paste flux (which looks a lot like axle grease)
2) I went back & forth along one row with the soldering iron's generously tinned tip while gently cranking with a pen knife till that side popped away from the board
3) Holding the IC with a needle-nosed (noodle-knees) pliers, I did the back & forth on the remaining row and pulled it gently away
4) I cleaned the pads with solder wick
5) I tinned a corner pin's pad and then situated the IC atop it and touched it again with the tip (verify proper alignment)
6) With a bit more flux and my generously tinned tip, and some extra solder at the ready, I did a drag-solder along the pins opposite the tack-soldered pin's side
7) I drag-soldered the remaining side
8) Finally, I wicked the bridges and did a close visual inspection

Next thing I know, I'm back on the air.

My tip is a pointed one (a Weller ST-7), but it's not of the fine tip or bent sort, no big deal.

Comments

  • WhitWhit Posts: 4,191
    edited 2010-09-16 19:44
    Does the outter darkness always lead one to the mysterious world of surface mount micro soldering?

    Congratulations! It is nice to try something like this and it works! Kinda makes you feel like a wizard.
  • HumanoidoHumanoido Posts: 5,770
    edited 2010-09-16 23:56
    Whit wrote: »
    Congratulations! It is nice to try something like this and it works! Kinda makes you feel like a wizzard.
    Whit, I think PJ Allen is THE WIZARD! His work with the BASIC Stamp is paramount and unprecedented. Whit, it is also really cool that you recognize and affirm the work of so many talented people on this forum.

    Humanoido
  • ercoerco Posts: 20,257
    edited 2010-09-17 00:38
    Hands of a surgeon! Nice to hear your Stamp repair success story, PJ. You've tamed your prodigal "magic smoke".
  • HumanoidoHumanoido Posts: 5,770
    edited 2010-09-17 05:34
    erco wrote: »
    Hands of a surgeon! Nice to hear your Stamp repair success story, PJ. You've tamed your prodigal "magic smoke".
    Definitely Hands of a Surgeon. I'm lucky just to see the pins! I'll probably need an electron(ic) microscope to do surface mount. We're lucky to have Parallax put the Surface Mount stuff on little boards ready for solderless breadboard plug-in. Looks like PJ has given us a mini-course in soldering. I greatly appreciate that! Thank you PJ.

    Humanoido
  • LeonLeon Posts: 7,620
    edited 2010-09-17 06:07
    Chip Quik is a safer way to remove surface-mount devices:

    http://www.chipquikinc.com/
  • PJAllenPJAllen Banned Posts: 5,065
    edited 2010-09-17 06:51
    No pads were lifted, there was no de-lamination, none of that. I didn't even burn my finger-tip. It couldn't have gone better.

    Chipquick is a package of stuff all of which some blokes may not have sitting around, but it looks the same as my procedure, for all intents and purposes, and I have all of the supplies on hand. If you have the soldering skills, but not the supplies, then Chipquick looks like a sound option.

    Since I didn't want to grip the BS2 pins, I placed the Stamp itself in a 24-pin socket which I then held in my Pana-Vise (Pana-Vise Jr., actually.)

    [Thanks everyone for your kind notice. ]
  • LeonLeon Posts: 7,620
    edited 2010-09-17 06:56
    Chip Quik has a low melting point, so damage to the board is very unlikely. Removing QFP chips is very easy.
  • PJAllenPJAllen Banned Posts: 5,065
    edited 2010-09-17 07:32
    [ Apparently there is a #### for every punch bowl. ]
  • RobotWorkshopRobotWorkshop Posts: 2,307
    edited 2010-09-17 11:45
    Glad you were able to get your Stamp fixed! I have another method for removing the chips that worked well for me. It may be something to try if you have to replace any more surface mount chips....

    All the steps are the same except for 1 and 2. Since the leads on the chip are tiny I've found that you can cut them on one side. You need to be careful not to nick the board however! With a steady hand I've used a new utility knife to sever the leads right at the package. From there just bend the chip back and the other side will break off. You can also use an exacto or a dremel to cut the leads.

    From there just use some fresh solder and the iron will pickup all the leftover lead parts and wipe them away on the sponge. A bit of solder wick makes the pads ready for the new part.

    Robert
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