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zapped my protoboard — Parallax Forums

zapped my protoboard

LitefireLitefire Posts: 108
edited 2007-04-12 10:28 in Propeller 1
well... somehow i managed to kill the propeller chip on my protoboard. somewhere on my robot a +12V lead managed to uncover itself, and after one last solid crash into a wall it was gone...

any ideas on how to revive it, if that is possible? for the time being i have my old board (a wulfden PRC) revived after 45 min of reworking solder joints... but i'd like to use the protoboard.

well, any ideas would be great. thanks so much
~~Brian

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2007-04-12 03:03
    If you really did get +12V power connected even briefly to any of the Propeller pins without some kind of current limiting resistor, there's no fixing it. A number of people have noted that the clock phase locked loop (PLL) seems to be the most sensitive structure on the chip since several have failed while the rest of the chip works (when running off the built-in RC clock). The telling behavior is that the Propeller Tool can identify the chip and download to it, but programs won't run (unless they use the internal RC clock).
  • LitefireLitefire Posts: 108
    edited 2007-04-12 03:07
    nope, i can't even identify/download to it. guess its a goner.

    oh well. not that bad, only ~$20.

    ~~Brian
  • mirrormirror Posts: 322
    edited 2007-04-12 03:08
    If you need to remove the chip form the board - to solder a new one - then use a tool with a with a cutting blade, and cut the pins from the chip before desoldering. This way you are·less likely to damage the surface mount pads.

    I have a Dremel tool, and the cutting wheel has very little wobble when running.

    The other method of removing a chip is using a hot air rework gun, but if you don't have the right tip, then you're probably going to burn the PCB.
    ·
  • LitefireLitefire Posts: 108
    edited 2007-04-12 03:11
    haha, i actually dont' own either a dremel or a rework gun... i use a cheepo soldering iron for most of my work. i'll probably just end up buying a new board, they're not that expensive... i just wish the demo board had more than 8 I/O pins, i like the layout so much better (with the sockets to plug wires directly in without soldering...)

    ~~Brian
  • Mike GreenMike Green Posts: 23,101
    edited 2007-04-12 03:33
    You can buy the sockets and solder them to the I/O pin connections. Another possibility is to use 0.1" header pins and use jumper cables (like Parallax's servo extension cables) to connect to an actual breadboard. Parallax's come with extra long header pins that you can insert into a breadboard and still plug in the sockets on the cable.

    You could also use the Demo Board and some kind of I/O extender. I like the PCA9554 which is an I2C 8-bit I/O extender. It has good drive capability and is easy enough to control (look at BoeBotBasic). You can put it in a socket ... It's much easier and cheaper to replace than a Propeller if you destroy it.
  • LeonLeon Posts: 7,620
    edited 2007-04-12 05:28
    ChipQuik works very well:

    http://www.chipquik.com/

    Leon
  • Graham StablerGraham Stabler Posts: 2,510
    edited 2007-04-12 08:15
    You can cut the legs off with a scalpel/Xacto and then desolder the nubbins with a normal iron. Then assuming you don't have solder paste tin the pads with a little conventional solder and then apply flux with a flux pen, place the part, tack opposite pins and solder the rest. Make sure you have really good light, daylight is the best.

    Graham
  • QuattroRS4QuattroRS4 Posts: 916
    edited 2007-04-12 10:11
    Well the 'good side' to this is that this will never happen to you again !! (and perhaps the benefits of optocouplers) ...... @ $20 I'd just go for the new board .. we don't have that luxury here in Europe yet though ...

    "A man's errors are his portals of discovery.” - James Joyce

    Regards,
    Quattro

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    'Necessity is the mother of invention'
  • mirrormirror Posts: 322
    edited 2007-04-12 10:28
    Graham Stabler said...
    You can cut the legs off with a scalpel/Xacto and then desolder the nubbins with a normal iron. Then assuming you don't have solder paste tin the pads with a little conventional solder and then apply flux with a flux pen, place the part, tack opposite pins and solder the rest. Make sure you have really good light, daylight is the best.
    If you don't have solder paste, then you should consider getting some. It·might seem expensive, but it actually gets used really slowly.·It's supposedly got a shelf life of six months, but mine is a year out of date and still works great - I just keep it in the fridge. How well it works compared to solder is hard to describe. It just simply works MUCH MUCH better. I suspect the six month life·is more for production use with automated machinery.

    I can second the really good light thing. I have a magnifying desk lamp which·does the job - I'd be happy with even more light, but the magnification is a good compensation.
    ·
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