5 ms·

I used to repair seismic nodes as part of my job. BGAs had the highest failure rate in high shock and temperature cycling environments by far. I find it worryin

I used to repair seismic nodes as part of my job. BGAs had the highest failure rate in high shock and temperature cycling environments by far. I find it worrying that so many chips are being designed with BGA. All it takes is one ball disconnect and you have a useless device without an expensive solder reflow. It seems like a really good way to design a device to have to be replaced after 5-10 years...

semi-extrinsic 10y ago
If MTBF is 5-10 years, that's comparable to existing HDDs/SSDs, no?
bravo22 10y ago
BGAs can be underfilled [1] to greatly increase mechanical reliability and shock resistance. 1. http://m.eet.com/media/1122054/0112esdnexlogic02.png http://m.eet.com/media/1122054/0112esdnexlogic02.png
- Certified 10y ago
  I have not knowingly seen this used in the wild but it looks intriguing. I've seen a lot of conformal coatings used to increase shock resistance but from my experience that is only half the battle. The thermal expansion and contraction can be the real slow silent killer. The caveat being that I was dealing with devices rated (and used) from -30°C to 85°C.
  - bravo22 10y ago
    It gets used quiet often, even Nest uses it [1]. Obviously proper heat management is important. 1. https://cdn.sparkfun.com/assets/8/5/c/7/4/52e157adce395f47598b4567.jpg https://cdn.sparkfun.com/assets/8/5/c/7/4/52e157adce395f4759...
akavel 10y ago
Anybody can explain what are "seismic nodes"? I tried googling it, as well as "repair seismic nodes", but to no apparent success
- Certified 10y ago
  I was referring to a seismic acquisition node used in geophysical exploration. Here is an example of a seismic node made by Sercel, one of the largest players in that market: http://www.sercel.com/products/Pages/unite.aspx http://www.sercel.com/products/Pages/unite.aspx
- gruez 10y ago
  Probably earthquake monitoring equipment
  - watersb 10y ago
    Petroleum companies search for oil via seismic analysis.

semi-extrinsic 10y ago

If MTBF is 5-10 years, that's comparable to existing HDDs/SSDs, no?

bravo22 10y ago

BGAs can be underfilled [1] to greatly increase mechanical reliability and shock resistance. 1. http://m.eet.com/media/1122054/0112esdnexlogic02.png http://m.eet.com/media/1122054/0112esdnexlogic02.png

Certified 10y ago
I have not knowingly seen this used in the wild but it looks intriguing. I've seen a lot of conformal coatings used to increase shock resistance but from my experience that is only half the battle. The thermal expansion and contraction can be the real slow silent killer. The caveat being that I was dealing with devices rated (and used) from -30°C to 85°C.
- bravo22 10y ago
  It gets used quiet often, even Nest uses it [1]. Obviously proper heat management is important. 1. https://cdn.sparkfun.com/assets/8/5/c/7/4/52e157adce395f47598b4567.jpg https://cdn.sparkfun.com/assets/8/5/c/7/4/52e157adce395f4759...

akavel 10y ago

Anybody can explain what are "seismic nodes"? I tried googling it, as well as "repair seismic nodes", but to no apparent success

Certified 10y ago
I was referring to a seismic acquisition node used in geophysical exploration. Here is an example of a seismic node made by Sercel, one of the largest players in that market: http://www.sercel.com/products/Pages/unite.aspx http://www.sercel.com/products/Pages/unite.aspx
gruez 10y ago
Probably earthquake monitoring equipment
- watersb 10y ago
  Petroleum companies search for oil via seismic analysis.