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1 year, 7 months ago.

Issue with board manufacturing?

I just received my mbed LPC1768 from Sparkfun. Tried downloading a program that blinks all 4 LEDs and it works fine. That's when I noticed what looks like an extra SMD component soldered with LED1. Is it supposed to be there? Is it a design revision, a sloppy fix, or a manufacturing flaw? Should I exchange it for a new one? I don't want to run into potential problems with it later.

It is white in colour with silver tips, so it's definitely not packing material. Tried tapping it gently but it doesn't move. It looks like an SMD resistor with one end soldered to one of the LED pads. The side facing up is coloured white, so it must be the bottom part of the component. The other end of the component doesn't seem to be soldered onto anything, but looks like it's touching the board. It's definitely not on the picture shown at Sparkfun: https://dlnmh9ip6v2uc.cloudfront.net/images/products/9/5/6/4/09564-02.jpg

Here's a picture of the board with the component encircled:

/media/uploads/maverickstudent/_scaled_mbed1768_solder_prob.jpg

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2 Answers

1 year, 7 months ago.

That looks like a stray resistor has dropped on prior to reflow. Definatley looks like it shouldn't be there. From the image it doesn't seem to contact anywhere but the LED. Should be ok to just wipe it off with an iron and forget about it.

Thank you so much for your prompt response! I'm not sure if removing it using an iron will void any warranties?

posted by Maverick Student 25 Jan 2013

Got the answer to that. Thanks.

posted by Maverick Student 26 Jan 2013
1 year, 7 months ago.

Hi,

Agree with Maverick War's analysis. It is a stray "extra" resistor, and so should be possible to remove it, possibly even without an iron, as it isnt soldered to any actual SMD pads.

As it was "extra", it wouldn't have shown up in production test, and those 0402 components don't exactly stand out when misplaced on a whole panel of mbeds!

Any problems, contact support@mbed.org

Thanks, Chris

Thanks for your reply. It pretty much seems soldered to one of the LED pads. Tried a bit harder but it's not coming off. It IS really hard to notice! I wouldn't have noticed either, had I not been looking very closely at the LEDs.

I have not had any problems and it's been working fine so far. I am in the process of programming it for my thesis project. Is it okay to remove it with an iron, in terms of any warranties? Especially since I also got word that I can get a replacement for it.

posted by Maverick Student 25 Jan 2013

Got the answer to the last question. Thanks.

posted by Maverick Student 26 Jan 2013

a fine tip soldering iron to the side of the LED its stuck on to reflow the solder and on that side of the LED and flick it off with a cocktail stick. Easy job to do if your handy with an iron. Or you could just leave it there , it wont do any harm.

posted by Maverick War 26 Jan 2013

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