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Internal corrosion on a circuit?

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This is a battery plate for a Sony NP battery, what would cause corrosion like this on it?
 

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Water, sea water, fizzy drinks. Electrolytes from the battery.

JimB
 
I'm guessing that the HALS process (or electroplating) left some exposed bare copper metal and the humidity in your environment was enough to cause some copper corrosion (note the light blue color of the copper hydroxide? The gold-plated plugs soldered to the copper with tin solder is also a Galvanic coupling that can cause even faster corrosion when condensation is present to act as an electrolyte. It didn't have to be exposed to water to get wet inside - moving your camera from a humid environment to an air conditioned environment can cause condensation inside the camera.
 
The wire insulation also has discoloured patches where it has been wet and then dried with sediments on it.

It looks to me as if it has a near perfect straight line across most of the board. The most obvious cause for that is free flowing liquid in the casing.
Condensation alone would not mark the insulation like that in any scenario I can think of; it's somehow been partly flooded.
 
The wire insulation also has discoloured patches where it has been wet and then dried with sediments on it.

It looks to me as if it has a near perfect straight line across most of the board. The most obvious cause for that is free flowing liquid in the casing.
Condensation alone would not mark the insulation like that in any scenario I can think of; it's somehow been partly flooded.
Yes, there's no doubt at all in my mind that it's been in water, and possibly salt water due to the extensive corrosion.

We used to get all kinds of equipment back under warranty (supposedly) with identical problems, without exception they all insisted it had never been near water.
 
It looks to me as if it has a near perfect straight line across most of the board.
We'd have to see if the PCB is slid into a slot or if other mechanical design is creating a "shadow" that blocks some condensation to create the straight line. But, in general, I'm guessing it is some type of corrosive urban or industrial environment - sulfur dioxide, ozone, nitrous oxides ("smog").

When I lived in Chicago many years ago, a local church used uncleared copper sheet as roofing material - each copper nail was filled with solder. They were hoping it would oxidize to a Statue-of-Liberty patina but it turned this chalky white/light blue in months and looked terrible. The heavy traffic and emissions of the cars and trucks of the 1970s did it in. Also, it was pretty thin sheet - the Statue of Liberty is almost 1/8" thick copper.
 
The wire insulation also has discoloured patches where it has been wet and then dried with sediments on it.

It looks to me as if it has a near perfect straight line across most of the board. The most obvious cause for that is free flowing liquid in the casing.
Condensation alone would not mark the insulation like that in any scenario I can think of; it's somehow been partly flooded.
Yeah it's no way it was flooded since it has always been mounted on my camera cage it has been fine but when it stopped supplying 12V on the output that's when I wondered what was up.. I didn't expect to see this inside at all I replaced it with a different brand and it works again but it's still baffling how it seemed to spread like that.

Since I got this back in 2021 I can't remember off hand how the packaging was when I opened it since I know some people send things back and Amazon makes it as if it's new.
 

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