LED not glowing [resolved]

[jake111]

Did the voltage test on the 1st PC board and the LED closest to IB is not glowing.

OA      76.5
IA        170.8
B-A/B  00.3
IB        171
OB      72.9

 

[Paul Birkeland]

Can you post some photos of your build?

 

[jake111]

Should I replace the stock pot? This one worked fine before the Speedball.

 

[Paul Birkeland]

It wouldn't hurt to put the stock pot back in, but it may not be necessary.  Can you unscrew the screws that hold the board on, flip it up, and take a photo of the underside? 

-PB

 

[jake111]

Photo:

 

[Paul Birkeland]

It probably wouldn't hurt to just reflow the joints on that side of the PC board. 

 

[jake111]

Reflowed and no change.

 

[Paul Birkeland]

Can you carefully measure the voltage on A2?

 

[jake111]

I just swapped the LED with one from the other PC board and works now. I think I got a bad one.
A2 is 00.5 mv

 

[Paul Birkeland]

If they sit around for a very long time in a humid environment, they can absorb moisture and fail during soldering.  This process takes a very, very long time though, from what we have seen previously one user left his Speedball kit in a damp basement for 6 months and had some LED issues when he went to use them.

 

[jake111]

Yep, that's it. The unstarted kit has been sitting in Hawaii since November and it's pretty humid here.
They're fine once soldered I hope?

 

[Paul Birkeland]

Ha ha, yeah that will definitely do it! 

Once they are soldered, you are good to go.  Somewhere there is a sheet of instructions for drying surface mount type LEDs in an oven, but honestly I would just order a pack of the spares and not worry too much about it. 

 

[jake111]

Thanks Paul