Most people know the smell of vintage/ancient electronics. There a lot of questions about this smell on forums, but nobody explains what the cause actually is or what the chemical formulation of this compound is. On most PCBs you can spot a liquid/syrup like layer of 'something.' What is this 'something', what kind of chemical is it?
To give you an idea what it looks like:
Most people on forums gave the advice to clean it with alcohol to remove/neutralize the smell, but I found that using alcohol (I used a 96% formulation) increases the smell. With a brush, it cleans off deep dust, residue and other stuff fine but it doesn't remove the smell. Actually alcohol makes it worse, the smell is two times (or more) intense. I think it has something to do that you are unable to remove the 'something' completely. The 'something' reacts with the alcohol. It is also possible that the 'something' penetrate the board because most of these boards are single sided brown (and brittle or porous over time) PCBs. I don't know if this combination is the cause of the smell.
The smell hard to describe, I will try to explain it:
A powerful penetrative distinctive characteristic smell with some chocolate or caramel sweetness to it and in some cases has a perfume like touch. It is a smell you can't ignore because when it reaches your nose it will stay there for a long period of time. In some way it smells toxic, a chemical reaction with something else.
I don't think it is flux because this smells very different, maybe a developer leftover solution? What do you think or better what do you know it can be?
Questions
- What is this (chemical) 'something' and why manufactures did't wash their boards before manufacturing? Is it still active doing something?
- Does the 'something' really smell like this or is it a product of chemical reaction with something else over time? If true, what is the cause the chemical reaction?
- Is it possible that this 'something' affect the lifetime of the PCBs and is it good to remove it anyway? For example it is covered for years with this 'something' and when you remove it the surface will be exposed to oxygen (and other gases.) Will it do more harm than good? When the 'something' stays there, is there any destructive effect noticable over time?
- Is it really possible to stop this fume/smell (after all those years) anyway?
