View Single Post
  #5   Report Post  
Posted to sci.electronics.repair
N_Cook N_Cook is offline
external usenet poster
 
Posts: 5,247
Default contaminated soldering surfaces

Smitty Two wrote in message
news
In article , "N_Cook"
wrote:

Peavey Prowler amp from 1999. All the 1/4 inch sockets and one , only,

of
the valve bases , bad solder joints, reacted to the re-soldering

process as
though the tags were made of stainless steel or had a grease/oil film

over
them. What could have been the cause?


The causes of corrosion are many. I know you enjoy failure analysis as
an independent intellectual pursuit, but it isn't going to help you in
the repair. Salt air, cigarette smoke, corrosive flux used by an amateur
in a previous repair, they all have the same remedy: Remove and Replace
affected components.



I did notice an amount of black copper sulphide? corrossion over the brass
of the stand-off power switches - more like usual 30 years of black from air
bourne sulphurous gases.
This was failure to solder onto the pins themselves, the pcb pad solder
adherence seemed ok.
I still tend to a production problem as just one valve base Belkin and, not
at component making, as the jack sockets are Ream UK. Maybe contamination by
flood or fire or something like that at pre-production parts storage . If it
was greasy hands of a procuction operative I would not expect both surfaces
of each tag and all tags to be affected