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damaged professional dev. board, repair info needed. — Parallax Forums

damaged professional dev. board, repair info needed.

Unit042Unit042 Posts: 21
edited 2010-06-28 14:27 in General Discussion
A while back, I was trying to use my Parallax Professional Development board to do something related to some project that concerned turning room lights on and off, but anyway, due to a lack of foresight, a couple of large valued capacitors (somewhere between 1,000 and 100.000uF each) charged at 16v ended up discharging through the Vdd and Vss connections. Big no-no.·nono.gif· After panicking a sufficient amount, I disconnected power. Once the metaphorical flames abated, I was able to determine that the pulse·generator took the brunt of the discharge, as whenever power was applied to the board, this part would heat up. (When I say heat up, I mean making my finger do this: jumpin.gif )

Squinting through a magnifying glass did not get me the part number, as the text was smudged and worn on the poor surface mount IC. Perusing the online parallax schematics of the board tells me it is a PIC12F629. This means I cannot simply order a new one from digikey.com (or other supplier), for it is not a logic chip; it is a microcontroller.

So, I present to thee these questions three:

1. Would it be risky to the other nearby parts if I used a bic cigarettte lighter to get the little SMT IC off? (Yes, soldering with the blue part of the flame is hard, but I have no hot-air tool yet, so this is what I'll have to use.)

2. How much will a replacement of just the IC cost?

3. If the cost is not excessive, what do I need to look out for when soldering the little bugger back in?

Any help or advice would be greatly appreciated.

Comments

  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2010-06-07 19:20
    Interesting...I have never seen anyone solder an SMD with a cigarette lighter. All I can picture is smoking solder-mask and melting parts (like the push button next to it).

    My advice would be to contact our Tech Support Dept. and see what your options are. You're focusing on the part you have determined to be damaged, but there are at least 5 other ICs on the board connected to the same supply rails that may have been damaged too and after replacing the one you know of, you could then have to address the others as well.

    I have seen someone with the right equipment replace the pulse generator only to have to replace the DS1307, MAX232E and of course the regulator and its caps. Definitely check with Tech Support on this one.

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    Chris Savage

    Parallax Engineering
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  • Unit042Unit042 Posts: 21
    edited 2010-06-10 16:45
    Excellent suggestion, I guess I'm off to tech support, but first...

    I'll put away the bic lighter (it works, but it is only a 'battlefield improvisation'), desolder the pulse generator, and then see what else is damaged. I'll just have to desolder until things don't heat up, then I can go for replacement pieces....

    Time to plug in the soldering iron! smile.gif
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2010-06-10 20:48
    If you contact Tech Support first they may be able to help you. If you attempt your own repair first they may be unable to help you.

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    Chris Savage

    Parallax Engineering
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  • HollyMinkowskiHollyMinkowski Posts: 1,398
    edited 2010-06-11 14:09
    I'd send the board to Parallax for repair.
    Don't they have some kind of a flat repair cost for
    things like the PPDB and demo board?

    This won't be an option if you try to solder it
    with a lighter though wink.gif
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2010-06-12 04:11
    I used to own a computer repair shop in NY and once a customer called and asked how much it would cost to fix his computer. After finding out what it was doing I gave him an estimate. When he brought the computer in I gave him a new estimate which he balked at. When he called he hadn't touched anything...but in between he and his best friend who really knows a lot about computers decided to have a try at fixing it themselves. The computer was brought in by his friend and some family with each one carrying a different part. His friend was sure some piece of hardware was bad and this guy thought he had saved me time because he had already taken everything apart making my job easier.

    The original problem was he had a virus which was causing startup items not to load and therefore drivers for video and sound weren't loading, causing those items not to work. It would have been a 15 minute job (I estimated 30 minutes). Actual time to fix his machine? Two hours after scrounging screws and cables from older machines.

    So to answer Holly's question...yes, for many things there is a flat fee, however, if the board is damaged deliberately that can change.

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    Chris Savage

    Parallax Engineering
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  • $WMc%$WMc% Posts: 1,884
    edited 2010-06-12 05:18
    Chris

    As hobbyist, We don't fall by the way side until all hope is gone.Usually it works to our benefit, But sometimes it bytes us in the rear.

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    The Truth is out there············___$WMc%___···························· BoogerWoods, FL. USA


    want speed?·want·to use the Propeller?·want to stay with BASIC___www.propbasic.com___


    You can feel stupid by asking a stupid question or You can be really·stupid by not asking at all.

    ·
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2010-06-12 18:29
    Yeah, and for the most part I am the same way. But if there is a chance that I can get an inexpensive replacement / repair I always try that first, then try it myself.

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    Chris Savage

    Parallax Engineering
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  • NWCCTVNWCCTV Posts: 3,629
    edited 2010-06-27 07:16
    Chris, I currently repair computers and have found that my best customers are the ones that have someone in the office that "Knows all about computers"!!!! It is usually after 2 or 3 hours of their messing with the system that i then get the call to fix what they broke and then fix the original issue!!!
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2010-06-27 17:37
    Yeah, while I do agree with $WMc% in so much as hackers (or wanna be hackers) need to try things for themselves while learning, I also think that in some cases you need to evaluate the situation. If you're a brain surgeon who doesn't know what pipe wrench is, you probably shouldn't be trying to repair that leaky faucet. The plumber shows up much happier when people try things like that before calling the professionals. =)

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    Chris Savage

    Parallax Engineering
    ·
  • bambinobambino Posts: 789
    edited 2010-06-28 14:27
    The boss brought me an Alienware Laptop once. The owner had sent it to a mechanic friend of my boss for repair. It wasn'nt getting power, So the mechanic took it apart and jumpered the fuse at the jack that had blowed. He got nothing but sparks after that. The mechanic asked my boss to get him out of the jam and so brought it to me.
    The fuse had blowed because the regulator after that fuse in the circuit was shorted to ground and burning a big hole through the board on the other side.
    The price of a regulator and fuse was nothing compared to the motherboard replacement. They ended up leaving it with us not willing to fix it!
    I love hacking, but only on things I've allready swallowed the loss on!
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