I have just purchased a secondhand NAP 160 circa 1972 and have opened it to replace the tants and large electrolytics. However, there is a white powder like substance on the circuit board under the polystyrene and the 220n open frame polyester cap-it looks like a stain and has a tide mark around the caps. There was some powder on the side of the 220n. It has brushed off easily, but I am now wondering if I should replace these caps as well. Do the polyester and polystyrene caps age? Should I replace them?Grateful for advice please.
Posted on: 16 June 2002 by Andrew L. Weekes
These are nothing to worry about, just some small residues left from the PCB flux cleaning process Naim use.
One of the downsides of environmentally friendly processes - they are often not as effective. Most Naim PCB's look quite dull as a result, often making solder joints look dry, although there is nothing wrong with them at all.
These film-type capacitors, as a rule, do not age like the polarised ones, and can be safely left alone.
How much difference did the recap make, and what components did you use?
Andy.
Posted on: 17 June 2002 by leslie
Andie,Thank you. I am in the process of recapping and will let you know how I get on. The residue was on the component side of the PCB and was only under the caps. The 220n open frame polyester was the worse with some residue on its side as well as underneath. Do you still think they will be alright?
