A right pain to desolder, double sided thin board, thin traces, tiny pads ,
plated thru holes and PbF solder. 19 inch rack amp but with unnecessary
miniature complex asymmetric switch impossible to find replacement for, 4
pole,3 way, but only 8 of the 16 pins used here. "re-soldered" with copious
flux before hot-air desoldering because of extra PbF temp . Not contacts
corrossion it would seem. I suspect sloppy phosphor bronze contact
carrier/slider in outer metal shell, will rebuild with 0.5mm hard PTFE strip
padding out one side to stop it flopping about, and cleaning contacts.
Maker YSC logo and also DC stamped on the outer.