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I've been trying to solder an SSOP 0.1" onto sparkfun's breakout board. However Somehow I've managed to short a positive to ground. Are there any tips you can give me in identifying it? I'm quite confused because I've sprayed and swapped with PCB cleaner/ IPA. I can't see any solder bridges on the pins. It doesn't appear to be a dead short as my meter telling me there's some resistance there. It also doesn't heat up right away.

I'm going to have to get a new breakout because I've managed to pull one of the pads off therefore am unable to through hole solder the wire.

Is there anything wrong ? I do remember having an issue with the usb not registering then after power cycling it worked. I found a short on my circuit across 5v and gnd on the regulator so removed the ft232rl then it disappeared. I found a short between positive and any gnd on the ft232rl while it wasn't connected anything. enter image description here

I used IPA and a pcb cleaner to clean off the type R flux I used to solder the ssop

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  • \$\begingroup\$ "some resistance there" - as in how much resistance? \$\endgroup\$ – Kellenjb Jun 27 '11 at 14:15
  • \$\begingroup\$ well it stops at 32.3ohms \$\endgroup\$ – Ageis Jun 27 '11 at 14:46
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    \$\begingroup\$ does it start near 0 then goes up to 32.3 ohms? If so it sounds like you are charging up a capacitor. Are you testing this in or out of circuit? \$\endgroup\$ – Kellenjb Jun 27 '11 at 14:52
  • \$\begingroup\$ Trace the location of the smoke :) But more seriously, look for heat, an IR camera is ideal but you can use almost any CMOS camera with a Near-IR filter on it can see hot spots. \$\endgroup\$ – Mark Jun 27 '11 at 15:07
  • \$\begingroup\$ @Mark - My experience with NIR filtered cameras is you don't get much until you are at ~400°F or more. At that point, things might actually be on fire. \$\endgroup\$ – Connor Wolf Jun 28 '11 at 3:46
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For that kind of package you should be able to see solder bridges with a jeweler's loupe. A jeweler's loupe is essential equipment for doing any kind of soldering these days.

Another possibility is that the solder connections are fine but that the part is going into latchup when turned on. This is particularly likely if any of the inputs are held above power, even for a brief time, during powerup.

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  • \$\begingroup\$ Sorry Olin, I'm very much a noob who's running before I can walk. What do you mean by latch up and why should there be continuity? \$\endgroup\$ – Ageis Jun 27 '11 at 14:53
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    \$\begingroup\$ @endolith: You're right I left one of the "e" out of "Jeweler's", but the loupe on my bench says "Peak Lupe 15x" on the side. I am aware that "loupe" is the official spelling, but is "lupe" perhaps a alternate? Of course it could be annoying cutesy branding on the part of Peak too. \$\endgroup\$ – Olin Lathrop Jun 27 '11 at 16:28
  • \$\begingroup\$ It might be an alternate spelling, but I figured this was more common regardless. \$\endgroup\$ – endolith Jun 27 '11 at 19:19
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    \$\begingroup\$ @endolith: OK, eyev nevver bin that gud at speling aneewae. \$\endgroup\$ – Olin Lathrop Jun 27 '11 at 19:30

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