Sprout Tech Help

[themachinerages]

I just finished the Sprout build. The LED is working when I press the switch but the effect does not turn on.

Any advice on how to fix this would be appreciated. Here are some photos:

http://imgur.com/a/pgjde

I haven't made any substitutions for parts (I followed the BOM on the Sprout pdf), and I haven't made any troubleshooting steps. I'm very new to this so I am kind of lost on the whole situation.

Thank ya!

[Haberdasher]

Hey man can we get a clear shot of the component side too?  Also what transistors did you use?

[jkokura]

These are the most common mistakes people make:

Incorrect Parts
Backwards Parts
Poor Soldering
Poor wiring.

You need to verify, then double check that all of those things are not your problem. Chances are one of them is. Go through your circuit and make sure your parts are correct, oriented properly, that you you have no cold solder joints or solder bridges and connections that shouldn't be made, and that your wiring is correct. From the looks of things, I would suspect one of those four issues, but the pictures don't really help me tell you which one.

An audio probe is the tool that can really help you at this point.

jacob

[mgwhit]

There are several spots on your board where it looks like you might have an accidental solder bridge to ground.  Use a multimeter to test for continuity to ground at every spot on the board where you shouldn't expect that.  Also, if you can post a backlit shot of the board, those can be amazingly helpful finding solder bridges on etched boards.  Good luck!

[themachinerages]

I don't have any of the tools mentioned to check, so I guess I'll ask around to see if I know anyone that does because I'd rather not go out and buy one (still not sure how much I want to invest in this hobby as I am just starting out).

@Haber - For Q1 I used 2N3904 and for Q2 I used BC109B

I will post those photos of the backlit board and the component side shortly

[ckim715]

Just a cursory look, I'm seeing a few possible solder bridges. Top left corner, the 3 big groups of solder points. Make sure there is continuity there, and there are no solder bridges. The top center solder point also looks to be a solder bridge. double check that one as well.

[themachinerages]

Could someone explain what a solder bridge is?

[Haberdasher]

It's where a tiny strand of solder extends from where you intended to put your solder to some other place on your board where it isn't supposed to be touching.  Thus it is "bridging" two places together.  They are hard to see sometimes, but having even one in a bad place on your board can make the entire circuit not work.  Testing for continuity can rule out or confirm there is a problem like that so that's a good place to start.  Re-flowing your joints can also fix dead joints if you have any of those, so it's probably not a bad idea either.

[themachinerages]

And what is reflowing? haha 

[jkokura]

Reflowing is applying a hot soldering iron to a solder joint to 'reflow' the solder on ye joint to make a better connection.

Jacob

[Haberdasher]

Yes exactly.  You're just re-melting every joint and then letting it re-solidify.  Sometimes you don't get a good connection the first time and this can fix it up.

[themachinerages]

I tired desoldering (with a desoldering bulb) a few of the points where it looked like bridges were formed but I didn't have too much luck. It looks like they are still there. Can anyone look at this picture and tell me what I should do?

(solder side)
http://i.imgur.com/mbMPP.jpg

(component side)
http://i.imgur.com/IGPxL.jpg

[ckim715]

http://i.imgur.com/JTFcC.jpg

In red are possible solder bridges that I saw. Make sure that there are no solder bridges at these points.

In yellow are solder points that I would hit again to make sure you have a good connection.

Do you have any desoldering braid? If not, you really do need to at least have that to fix mistakes.

[chromesphere]

EDIT: lol we both posted the same thing

Hi themachinerages,

You need to be very careful when soldering that you dont accidentally connect something thats not supposed to be connected (a solder bridge).  I would recommend practicing your soldering on some vero board, just to get the basic feel for how to do it.  You dont want to put too much solder on, and you dont want to put too little solder on either.

I have edited your photo to show you a couple of places that you might want to check for solder bridges.  I have also included the corresponding PCB layout, so that you can see what i was looking for (there should be a gap, but there isnt).  Some of them may not be solder bridges, its hard to tell from the photo but i have included them so you can check them anyway.  I would suggest following that pcb layout around your board with an exacto knife / sharp knife and lightly scratching the gaps between the tracks, scratch away the flux (the translucent, browny / yellowy stuff) and check for solder bridges.  Go around the hole board methodically.

I hope this helps you to get the board going.  Stick with it mate, its worth it trust me
Paul

[ckim715]

Looks like Chromesphere and I saw similar things. Go back to the solder pads that we pointed out and double check them