Author Topic: Dealing with failure, loss of time when things blow out.  (Read 1280 times)

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Offline WebsteriaTopic starter

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Dealing with failure, loss of time when things blow out.
« on: August 30, 2019, 05:58:24 pm »
So I’ve been attempting to build this stupid rainbow clock kit. I just soldered the processor in, super careful not to overheat, but had a few shorts when I first turned it on. It acted odd so I turned it off and fixed the shorts. Apparently that act blew out the processor because all the leds are receiving straight 5V and are blown out. This means I have to start on a new one for the fourth time. I am dedicated to this but this design makes me concerned. One small error means countless hours of work. I’m sure this happens to large companies right now too but I feel really kind of down on myself about it.

I’m sure some of you have gone through this. Tell me your stories.

Incidentally my next project will not have a qfn44.
Just starting out... be gentle.
 

Offline TheHolyHorse

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Re: Dealing with failure, loss of time when things blow out.
« Reply #1 on: August 30, 2019, 06:22:28 pm »
I'm working on a little PSU project (like everyone else) and it has a MCU in a QFP48. I soldered it like a month ago (first time soldering smd stuff) and that worked out just fine. But after soldering everything I realized I had made a mistake with the layout. I had spent so much time on the schematic and also the layout and I felt really good about it, only to get a punch in the face with an epic fail because I missed ONE LINE of text in the datasheet. |O |O

So you're not alone beginners make mistakes, hell even experienced people mess up from time to time. Don't be afraid of making mistakes, it really sucks when it happens but in the end you're just learning. Mistakes are the best way to learn so don't be afraid keep working and you'll come out just fine with a working thing. :)
 
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Offline WebsteriaTopic starter

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Re: Dealing with failure, loss of time when things blow out.
« Reply #2 on: August 30, 2019, 06:37:01 pm »
I use a flat round tip for my drag soldering. I’ve had issues with bridges that get REALLY hard and require much higher temps when I’ve used hot air and solder pasts.  I also am not quite as comfortable with it.

Also, with this being a kit don’t you think they would’ve put protection in for this? Seems like bad Chinese design sadly.
« Last Edit: August 30, 2019, 06:46:19 pm by Websteria »
Just starting out... be gentle.
 

Offline TheHolyHorse

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Re: Dealing with failure, loss of time when things blow out.
« Reply #3 on: August 30, 2019, 07:01:01 pm »
Easiest way to deal with solder bridges as far as my experience goes has been solder wick.
 

Offline fourfathom

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Re: Dealing with failure, loss of time when things blow out.
« Reply #4 on: August 30, 2019, 07:53:16 pm »
Use a variable power supply when powering up a new board.  Start at 0V and slowly increase, watching the current as you go.  Current is usually needed to blow things up, so you can catch a lot of problems before they become catastrophic.
We'll search out every place a sick, twisted, solitary misfit might run to! -- I'll start with Radio Shack.
 

Offline Kilrah

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Re: Dealing with failure, loss of time when things blow out.
« Reply #5 on: August 30, 2019, 08:39:05 pm »
Even better, use a supply with a current limit and set it properly.

So I’ve been attempting to build this stupid rainbow clock kit. I just soldered the processor in, super careful not to overheat, but had a few shorts when I first turned it on. It acted odd so I turned it off and fixed the shorts. Apparently that act blew out the processor because all the leds are receiving straight 5V and are blown out. [...] One small error means countless hours of work.
Well, you learned that firstly you measure for continuity and shorts before applying power, and that anything you can disconnect you leave out until you verified what it's connected to is working properly enough to not destroy it.
You know errors will happen, so you do what you need to catch them before they lead to problems.

This means I have to start on a new one for the fourth time.
Or not, since you wouldn't have done that 3 times...
When you find a problem you do something about solving it, you don't just stab in the dark trying the same thing again over and over hoping it'll magically work at some point.
« Last Edit: August 30, 2019, 08:41:16 pm by Kilrah »
 

Offline WebsteriaTopic starter

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Re: Dealing with failure, loss of time when things blow out.
« Reply #6 on: August 30, 2019, 08:55:12 pm »
You’re absolutely right. Each time it was a different problem. I’m convinced each time it was shorts that I didn’t check for. I’m angry at myself but how can I have experience I don’t have. Also although I did it three times it was less experienced at first. By now I’m pretty well versed. I can do the smd leds no problem.
Just starting out... be gentle.
 

Offline Kilrah

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Re: Dealing with failure, loss of time when things blow out.
« Reply #7 on: August 30, 2019, 08:59:27 pm »
You’re absolutely right. Each time it was a different problem. I’m convinced each time it was shorts that I didn’t check for.
So it wasn't a different problem ;)

 

Offline fourfathom

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Re: Dealing with failure, loss of time when things blow out.
« Reply #8 on: August 30, 2019, 10:41:57 pm »
Even better, use a supply with a current limit and set it properly.

I do that too, but I'm always afraid that the output filter caps will still provide a spike of high current.  So I *slowly* crank up the voltage.

Wait -- I admit it -- I usually just flip the switch or plug it in or connect the wires (and pray).  But when it smokes I do wish I had followed my own advice.
We'll search out every place a sick, twisted, solitary misfit might run to! -- I'll start with Radio Shack.
 

Offline Twistedsnail

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Re: Dealing with failure, loss of time when things blow out.
« Reply #9 on: September 02, 2019, 10:38:26 pm »
Don't feel too bad about this sort of thing, it's part of the learning process!
I bet each time you've f*cked it up, you've learned something from it right?
To make you feel better I'll tell you something stupid I did:

I was in my honours year (final year + pre-masters) of my electronics engineering degree.
I was working on a rehabilitation device that robotically (and adaptively) performs physio to improve the user's fine motor skills after suffering a stroke.
I had lots of experience with electronics and programming building power supplies, audio amplifiers, computer vision, video games, area-mapping robots etc.

I blew up a single MOSFET in my motor control circuitry maybe 50 times before I figured out what was causing the issue.
The issue was I had misread the datasheet for one of my ICs and it needed replacing.
I wasted about $200 and 1/4 of my project's time-budget on something that at my level of education and experience was completely trivial.
And then I purchased the wrong sized motor from a supplier and didn't find out for a few weeks because of lead times.
My final thesis had about 20 pages on the things that went wrong in excruciating detail. I got an A+.

I can guarantee you that I haven't made those mistakes again. Learn from what you've done and you'll be fine  :)
 

Offline Jwillis

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Re: Dealing with failure, loss of time when things blow out.
« Reply #10 on: September 04, 2019, 07:06:14 am »
Take it slow and try not to rush. If you find yourself getting frustrated take a break.
Don't be afraid  use lots of flux.Lightly tin the pads first .Just tin the iron and solder from the pins outwards.You'll have to tin the iron several times .This seems to work best for me because I tend to be very shaky.A good set of magnifying glasses helps a lot.I just use a set of off the shelf 4X reading glasses and lots of light.

Don't get yourself down.I'm learning to and blow things up all the time.Fried 2 frequency generators on tube radios before I realized I should have had a small cap between it and the radio .say la vie
 


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