Katrina-ed

[loriana]

Interesting...

Ever see what happens to circuit boards that have been exposed to sea water?

Wellllll.....

Comments

[keeganfox]

Is that still "warranty" work though?

[loriana]

I would say a resounding "NO" personally... BUT... I am not the one calling those shots. My guess is what happened is that the distributor accepted the thing and gave an exchange or refund or something with no knowledge of what was really wrong with it.

*shrug* Really this is not my problem. I design the circuitry, and have had nothing to do with making it water tight or how it is packaged... believe me much would change if it were up to me.

[fuzzytoedcollie]

Another consideration: trucks driven in northern states during the winter would be exposed to lots of salty slush spray from salt spread on the roads.

If the housing containing the printed circuit board isn't weather/waterproof, or the gasket fails, you might see similar corrosion?

[loriana]

Technically if its a gasket failure we got other bigger problems as well. The way the mechanics of the thing work is that the same gasket that would keep water OUT of the circuit board area, keeps brakefluid out of the circuit board area as well... and it would mean that all the brake fluid would have drained out of the unit entirely.

:P
still.. all these things (assuming either a katrina like event, or gasket failure) arnt really my problem, though obviously I have to indicate "Hey!, this is NOT a circuit problem! This is water getting into the unit somehow".

... But I just find this highly amusing.

[lobowolf]

That certainly looks like water damage. I see a lot of boards that are dropped into fresh water, and the result is no better. Even in "fresh" water, there are enough dissolved ions and minerals form a fine white corrosive powder that eats away at the traces.

It could, as fuzzytoedcollie mentioned, be caused by salt spray intrusion. The real key would be to check all around the rubber seals. If it appears that the water came in from all sides, I'd say it's been Katrina-ed. If it looks like the entry is only from one place, it could have been a gasket failure. The likelyhood of water intrusion during normal use would be a combination of how good the seals are and where the unit resides in normal operation.

Most of the portable radios I work on are rated as "weather resistant," meaning they will withstand some rain or water spray, but there are only a few models rated for entire immersion (and those require yearly recertification by the manufacturer to verify seal integrity).

[lobowolf]

From the picture, it looks like water came in from all side..probably immersion.

[loriana]

That board that was shown is actually one of the best looking ones of the bunch!

Yeah.. its clear that they were totally under water.

[nrasser]

You wouldn't think it, but this is something that is quite an issue up here in the north states. People of shady ethics bring flood-damaged cars up here from the south to sell all the time, as the folks around here have no concept of what saltwater flooding will do to a car's electronics and they don't think a bit of water damage should hurt them much...and it doesn't, when the cars are flooded with FRESH water like occasionally happens around here.

The electronics can fail in any number of ways. Typically the connectors will oxidize and create the initial failures, then the rest of the system slowly succumbs to corrosion damage and leakage as humidity keeps the salt active, building massive repair bills.

[animist]

And let's not forget all that damn salt water off of the roads in the winter! I could always tell a car from the northern states when I was on base in the Navy out in California, before I ever saw the liscence plate.

[animist]

A lot of the electronics I worked on in the Navy had a thick conformal coating on it, to protect against corrosion like that. And the wire can be protected somewhat by using tinned wires with... I'm not sure what composition of solder. There are ways to help deal with things like that. I agree that it sounds like your electronic components are not the weak point; it's the pcb itself. take care!

[shockwave77598]

Solder is lead and tin.

[animist]

I hate to sound annoyed, but I know the that solder is made of lead and tin. What I did not know was the specific composition of the solder used in maritime environments. In exmaple, some solder is 60% lead 40% tin, the 24 guage multi-core I use at work is 63% lead 37% tin, and so on. Sometimes solder has silver in it as well, or other elements, in small amounts. Other times it does not have lead, such as the RoHS compliant stuff used in Europe. Sorry - I shoudl have been more specific in my post.

[shockwave77598]

No worrys. I wasn't being insulting - I don't know what your level of knowledge is. I thought your question was of a general nature. 63/37 is the most common that I know of because it's eutectic.

Course nowdays with this Rohs push, it isn't the case anymore. Rohs is going to cause big problems soon. Pure tin (especially flashed tin) creates a little understood problem called "tin whiskers". Micron sized filaments of pure tin pump out of the metal and create shorts of all kinds. It takes a couple of years to show up, but hardware made with Rohs parts may have shortened lives or suffer sudden complete failure for no obvious reason.