Dealing with failure, loss of time when things blow out.  - Page 1
Forum section: electronics / beginners

author: Websteria
author_rank: Contributor
timestamp: August 30, 2019, 05:58:24 pm
content: 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.

author: TheHolyHorse
author_rank: Regular Contributor
timestamp: August 30, 2019, 06:22:28 pm
content: 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.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.

author: Websteria
author_rank: Contributor
timestamp: August 30, 2019, 06:37:01 pm
content: 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.

author: TheHolyHorse
author_rank: Regular Contributor
timestamp: August 30, 2019, 07:01:01 pm
content: Easiest way to deal with solder bridges as far as my experience goes has been solder wick.

author: fourfathom
author_rank: Super Contributor
timestamp: August 30, 2019, 07:53:16 pm
content: 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.

author: Kilrah
author_rank: Unknown
timestamp: August 30, 2019, 08:39:05 pm
content: Even better, use a supply with a current limit and set it properly.Quote from: Websteria on August 30, 2019, 05:58:24 pmWell, 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.Quote from: Websteria on August 30, 2019, 05:58:24 pmOr 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.

author: Websteria
author_rank: Contributor
timestamp: August 30, 2019, 08:55:12 pm
content: 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.

author: Kilrah
author_rank: Unknown
timestamp: August 30, 2019, 08:59:27 pm
content: Quote from: Websteria on August 30, 2019, 08:55:12 pmSo it wasn't a different problem

author: fourfathom
author_rank: Super Contributor
timestamp: August 30, 2019, 10:41:57 pm
content: Quote from: Kilrah on August 30, 2019, 08:39:05 pmI 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.

author: Twistedsnail
author_rank: Contributor
timestamp: September 02, 2019, 10:38:26 pm
content: 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 asingle MOSFETin my motor control circuitry maybe50 timesbefore 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

author: Jwillis
author_rank: Super Contributor
timestamp: September 04, 2019, 07:06:14 am
content: 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