Environmental tests

[Boomerang]

I have questions for the people who need to test their designs in different temperatures and/or humidity: how do you test your board or devices - do you own a environmental chamber or you rent for some test sessions or you go to a lab to test? What is the best option for you personally? Do you need to test for humidity or you test only for temperature?

[Tomorokoshi]

We have a few options for environmental tests. The most extreme does vibration, temperature, and humidity. It cycles through these several times. It takes a few hours.

Here are the types of failures we find:

1. Humidity is usually taken care of by conformally-coating every board.

2. Only a few things go wrong at low temperatures. Usually not much worse than contrast changes on LCD displays.

3. Several things can go wrong at high temperatures:
  - LCD contrast changes
  - High-load devices can go into thermal shutdown
  - Devices can have odd behavior

4. Vibration can rip large components right off the boards. Usually fixed by using epoxy when manufactured.

Some real odd ones can show up. I had a diode soft-short at high temperatures, which caused another component to burn up. It took about a week to figure that one out.