Connect with us

PCBs, Moisture(?), Capacitance and Temperature

Discussion in 'Electronic Design' started by EdV, Apr 4, 2008.

Scroll to continue with content
  1. EdV

    EdV Guest

    We got a batch of boards built and two of them show a curious
    tendency(consitent) to shut down the crystal oscillator at -20 C. We
    also notice that the capacitance of the xtal caps changes more on the
    "bad" PCBs at -20C than the "good" boards.

    1. Moisture in PCB Layers that didn't get baked out?
    2. Uncured epoxy betweem layers?
    3. Residual flux?

    #3 I could address with vapor degreasing or other cleaning. #1 and 2
    would mean baking at 100C or so which I guess is ok to see if it has
    an effect.

    Any thoughts, insights or expereinces as always are welcome.

    Ed V.
     
  2. neon

    neon

    1,325
    0
    Oct 21, 2006
    if you got moisture then baking the water out is not tht solution get the board hot then cooling it down power-off will claim all water particles from the enviroment. solution conformal coating like cheap old warnish will do it. dipping is better then spraying.
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-