Some Glues Don’t Mix with Electronics

I completed my AVR alarm clock project just yesterday. Today, I took a few minutes to program a patch that would enable the clock to save the alarm settings into EEPROM, enabling them to survive power outages. When the time came to flash the new firmware into the clock’s memory, I encountered a bad surprise: it didn’t work, my usbasp programmer gave me an error message saying that the target wasn’t responding.

This puzzled me. I was able to flash the firmware just fine less than 24 hours prior. Could I possibly have done something to damage the microcontroller? Could I have burned out its in-system programming (ISP) port somehow? I experienced a mix of disappointment, frustration and sadness for a few minutes, and then a thought occurred to me: it could be the glue.

I used simple No More Nails adhesive to stick velcro strips to the underside of every circuit board. Possibly, this could have caused some damage overnight. I removed the microcontroller board, and sure enough, there was a green corrosion mark just where one of the trace goes from the microcontroller to the ISP connector.

Not wanting to waste a $15 board, I attempted a simple repair: I soldered a wire across the trace and secured it in place with hot glue (which doesn’t seem to corrode things). I was then able to upgrade my clock’s firmware. I’ll be keeping the No More Nails glue away from sensitive electronics in the future.