Audio Shield and flash chip

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dsparks

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I have soldered many Teeny 3.1s and Audio Boards (shields) together. As well as soldered many flash chips to the Audio Board. I have had one in particular for approx. 1 year running as my test board. Until recently, the board was operating just fine. It has since stopped producing audio. After much investigation of the audio output, pins and hardware tests. I have found that my flash chip is shorting out on pin 2. Which is the pin that goes directly to pin 12 on the Audio Board. By shorting out, I mean, when checking for continuity on ground, pin 12 and pin 2 of the flash chip, make continuity. This should NOT be the case. But is obviously the cause of my problem.

The question now is, why after all this time, has this happened!?

Is this an issue of using flux when soldering the flash chip?

Any insight and help into solving this will be greatly appreciated.


Thank you!
 
dsparks said:
The question now is, why after all this time, has this happened!?
Click to expand...

Perhaps it was nearly shorting all this time, and cycling temperature or other minor stress causes 2 conductors that were nearly touching to finally short?

Any insight and help into solving this will be greatly appreciated.
Click to expand...

For shorts, sometimes different techniques are needed, depending on whether you want to simply fix the problem or get to the bottom of how it happened.

To just fix things, reflowing the solder joints with extra flux is a good first step.

To investigate, cutting traces to isolate sections of the board is usually done. Then you can narrow down exactly where the actual short is.

I should also mention the test current used by some multimeters in continuity (beep) mode can be fairly high. Some meters can damage ICs in this mode. Normally the highest impedance mode (the one for megaohms) is best to use. Always remember your multimeter is injecting test currents in these modes and measuring the resulting voltage. It's not a purely passive measurement like measuring voltage.
 
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